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2.8 Low RPM Hesitation by Boostdreamer
Started on: 10-23-2013 11:26 PM
Replies: 68 (2698 views)
Last post by: Boostdreamer on 07-05-2014 11:54 PM
Boostdreamer
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Report this Post10-23-2013 11:26 PM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
I'm starting a new thread because my original one, "I think I have a rod knock" http://www.fiero.nl/forum/Forum2/HTML/130334.html has served its purpose and now the subject has changed. Hopefully it will attract more responses about other's experiences.

I just swapped engines in my 86 Auto GT w/air. I put my 87 2.8 in it. The 87 was with a 5-speed Getrag. I kept the 86's Automatic and wiring harness. I also used the 86 plenum and throttle body, injectors, sensors, alternator, etc. The only part of the 87 that I kept was the block, heads, oil pan, lower intake, harmonic balancer, and thermostat housing/filler.

My main problem is a stumbling hesitation from about 1300 RPM's to 2000 RPM's. This is an intermittant problem. It doesn't always happen when cold or hot. It doesn't always happen when I slow for a 90* turn. It kinda feels like water in the gas when the problem is happening. No power. Once it builds past that point, it runs great! It always starts easily on the first crank. It always idles nicely at 800 RPM's. When in Park or Neutral, the throttle response is perfect. There is no indication of an RPM-sepcific problem. This only happens when in gear and trying to move.

The hesitation problem had been worse and almost happened every time the RPM's got into that range. I replaced the Intake Air Charge Temperature sensor and it cut the frequency of the problem about in half and it reduced the severity of each episode from complete aggravation to annoyance.

I'm only getting one code and that is Code 45 - Rich Fuel Condition. The code problem is also intermittant if it is only happening when the SES light is on. The hesitation does not seem to trigger the SES light in any way. I don't know if one is a symptom of the other.

I have done a bunch of parts swapping to see if anything makes a difference.
3 different coils
2 different ICM
3 different MAP
2 sets of spark plug wires
Replaced spark plugs
New fuel filter
Fluid levels are good
Adjusted timing but could still be off (China Freight timing light died before I could confirm it was tightened down in the right spot)
2 different thermostats
2 different ECM coolant sensors
unplugged the Cold Start Injector switch
Relaced the EGR Solenoid
Checked the EGR Valve to confirm it holds vacuum
Checked all vacuum lines and connections
The O2 sensor is about 2 months old

What am I missing?


------------------
Jonathan

'68-69 GTO Nose - The Project has Begun!
My '85 L67 Build Thread

[This message has been edited by Boostdreamer (edited 11-20-2013).]

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Report this Post10-24-2013 10:25 AM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
Sometimes it backfires when it stumbles.

It never feels like it will die and it never has.

Jonathan
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Report this Post10-24-2013 11:32 AM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
Is it possible that the new engine, after sitting for so long, could have had a build-up of rust or something and when released, it clogged the O2?

Can O2 sensors be cleaned? Soaked in degreaser?

It seems like more of a sensor or electrical issue than a mechanical issue to me. What do I know, though, right?

Jonathan
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Report this Post10-24-2013 11:34 AM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post

Boostdreamer

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Could porting the exhaust manifolds have anything to do with it? The restrictions were cut out. Does this require a modification to the PROM chip?

Jonathan
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Report this Post10-24-2013 06:40 PM Click Here to See the Profile for RaydarClick Here to Email RaydarSend a Private Message to RaydarEdit/Delete MessageReply w/QuoteDirect Link to This Post
Porting the manifolds won't hurt anything.

It bogs and stumbles. It backfires. The ECM thinks it's rich. It's going to remove as much fuel as it can, even if it's not really rich.
It's probably setting the code and turning on the light when it's removed as much fuel as it can and still thinks it's overly rich.
In reality, it's probably running lean. (The bogging and backfiring would tend to support this.)

Do you smell gas? I'm guessing that you don't. I'm guessing that it smells hot, if anything.
You may also be getting spectacular gas mileage.

I would be inclined to tell you to unplug the O2 sensor and see how it acts. It might be lying.
(The one in my 4.9 "lied" in the other direction. Told the PCM that it was running "dead lean". The PCM responded by dumping in as much gas as it could. Failed a smog test in a most spectacular manner. My catalytic converter died shortly after that, even though I had replaced the faulty O2 sensor.)
If you unplug the O2 sensor, the "rich" code will go away, but you'll get a new code for the "missing" O2.
If that fixes your driveability issue, I would be inclined to replace the O2.
The one that my 4.9 "ate" was a GM sensor. Other people say that they hate Bosch sensors.
I would be inclined to buy a Denso or NTK. My 4.9 currently runs an NTK. YMMV.
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Report this Post10-24-2013 07:30 PM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
Guess what brand of O2 sensor I have?!! Yep, Bosch!

I'm starting to suspect that the hesitation is a transmission issue. I used 1,2, and D like a manual trans and there was no problem. I think it might not be shifting down like it is supposed to. Is that a TV cable issue?

Jonathan
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Report this Post10-24-2013 07:53 PM Click Here to See the Profile for RaydarClick Here to Email RaydarSend a Private Message to RaydarEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Boostdreamer:

Guess what brand of O2 sensor I have?!! Yep, Bosch!

I'm starting to suspect that the hesitation is a transmission issue. I used 1,2, and D like a manual trans and there was no problem. I think it might not be shifting down like it is supposed to. Is that a TV cable issue?

Jonathan


Hard to say.
At wide open throttle, with the selector in Drive, it ought to shift at about 5300, IIRC. If it shifts too much sooner than that, or the shifts feel soft, particularly the 1-2 shift, it needs to be adjusted.
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Report this Post10-24-2013 08:04 PM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
So does the TV cable only control the up-shifts? Does it have a "kick down" cable or an equivalent?

Jonathan
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Report this Post10-24-2013 10:00 PM Click Here to See the Profile for MarkSClick Here to Email MarkSSend a Private Message to MarkSEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Boostdreamer:

Guess what brand of O2 sensor I have?!! Yep, Bosch!

I'm starting to suspect that the hesitation is a transmission issue. I used 1,2, and D like a manual trans and there was no problem. I think it might not be shifting down like it is supposed to. Is that a TV cable issue?

Jonathan


Check the O2 sensor again. My exact problem. See below. Bosch POS.

http://www.fiero.nl/forum/A...130314-2-108425.html

BR's,

Mark
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Report this Post10-25-2013 12:43 AM Click Here to See the Profile for mitchjl22Click Here to Email mitchjl22Send a Private Message to mitchjl22Edit/Delete MessageReply w/QuoteDirect Link to This Post
Could also be a vacuum leak somewhere. If you know anyone with a shop or a smoke machine, you could diagnose that problem pretty easily.
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Report this Post10-25-2013 09:14 AM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
Going to work some more on it today. On my list today is to change the front spark plugs and inspect the old ones. The rear plugs looked nice and clean and tan. I'll also try to adjust the TV cable. Once those two jobs are done, I'll test drive to warm it up and see if I can get my cheap China Freight timing light to work just a little more. If not I'll go buy a new one since I can't rent or borrow one.

I do know all the vacuum lines are solid and connected correctly. The connecting ends could be stretched and looser than ideal. Because of the previous posts, the O2 sensor is back on my radar as the likely cause of the code.

Jonathan

[This message has been edited by Boostdreamer (edited 10-25-2013).]

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Report this Post10-25-2013 02:04 PM Click Here to See the Profile for RaydarClick Here to Email RaydarSend a Private Message to RaydarEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Boostdreamer:

So does the TV cable only control the up-shifts? Does it have a "kick down" cable or an equivalent?

Jonathan


The TV cable is not really a "kick down". That's a popular misnomer. It does have that function, though.
It should downshift even at part throttle, depending upon engine load and RPM.
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Report this Post10-25-2013 02:12 PM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
I got the spark plugs in and I attempted to adjust the TV cable. I don't know if it moved in any way. It seems to have a light resistance for a couple of inches then a stronger resistance as is proper according to the Haynes manual. I didn't find any real "slop" on the engine end of the cable. I'm about to go for a test drive and I doubt I'll see any change. I'm leaning towards timing and O2 sensor at the moment.

As for the spark plugs, it wasn't too bad. Since I recently had the cradle out and since I put anti-seize on the bolts I knew I could get the rear bolts out without much fuss. I took one of the dog bone bolts out and stood the dog bone up. I removed the air filter snorkle. I put the car on jack stands which I placed forward of the cradle in the triangular indentions in the frame. Then I put my jack under the rear lateral portion of the cradle and lifted from there a bit more to make sure there was no stress on the cradle bolts. I took the bolts out and used the jack to lower the cradle a few inches just before the coil cooling tube came into contact with the coil. That opened a bunch of room on top so I stood in the trunk and replaced the plugs. Not too bad at all compared to trying to get your arm in there otherwise. On the bright side, the old plugs looked like the rear bank, old but clean and tan.

Gotta go drive.

Jonathan
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Report this Post10-25-2013 06:13 PM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
The plugs and timing has helped a bit more. The timing was about 11 degrees BTDC. Now it is more like 9 degrees. I gapped the plugs a little on the big side also. I don't understand how people can index their plugs. They just turn and then they seat. No room for adjustment.

The SES light didn't come on after adjusting the timing. I doubt it is cured. It will prolly show up again and I'll have to buy a better O2 to fix it.

I'm 99% sure the rest of my hesitation problem is coming from the trans. I think it is not shifting down correctly. I think it does it right over half of the time but not always. I have a new filter and gasket for it. Could it be that the fluid is old and the filter is full? Maybe I should put some sort of treatment in it for a while before changing it. Has anyone had good experience with Sea Foam in their trans?

Jonathan
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Report this Post10-25-2013 06:49 PM Click Here to See the Profile for FieroDan86Send a Private Message to FieroDan86Edit/Delete MessageReply w/QuoteDirect Link to This Post
I had many of the same problems you describe on my 88GT: bucking and hesitation at low RPM's. In my case, the engine would buck, hesitate and put up a fight if I tried applying power in any gear below 1500 rpm. Note that mine is a 5spd Getrag. I did not have any codes either. My car is a bone stock, CA emissions legal (and in compliance) very high mileage (290,000 miles) example of Pontiac's finest.

After replacing the O2 sensor with a new Denso unit and replacing the entire ignition system (new Cardone select distributor, MSD Blaster coil, Taylor wires and NGK copper plugs gapped to stock specs) the car idled like a kitten and pulled strong in any gear from any RPM as low as 1000. Biggest difference I have seen in a tune up since the days of points ignition!
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Report this Post10-25-2013 06:59 PM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
I'm going to try SeaFoam Trans Tune. I honestly believe all my ignition stuff is working correctly.

Jonathan
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Report this Post10-25-2013 07:35 PM Click Here to See the Profile for RaydarClick Here to Email RaydarSend a Private Message to RaydarEdit/Delete MessageReply w/QuoteDirect Link to This Post
Unplugging the O2 sensor is free. Takes about a minute.
Zip tie the pigtails up so they don't get against anything hot and melt.

Drive it that way for a few days and see what happens.
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Report this Post10-26-2013 12:26 AM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
What should happen?

J
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Report this Post10-27-2013 11:04 AM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
Good news and bad news:

Good news first.
No codes, everything is fixed, and the car is running better than ever before! While it may seem like I took the long way around solving this problem, this method did reveal some things that otherwise would have gone uncorrected. In my attempt to isolate the single common cause of my hesitation, lack of power, backfiring, and Code 45, I learned that some problems can occur and not be associated with codes at all. It is my firm belief that the Code 45 condition was strictly due to a faulty Bosch O2 Sensor. That Bosch sensor was just a few months old when it failed. Granted that starting this engine with that sensor in place after it had sat unused for a few years may have played a roll in its demise, I will still never waste my money on a Bosch O2 Sensor again. I replaced it with an AC Delco unit. $71 at Advance but $69 after using a coupon. Added to the cost of the Bosch sensor, I've got about $100 in O2 fixes.

So, what else did I learn?
1. I learned that my Intake Air Charge Temperature Sensor was bad or going bad. Changing it improved my issues other than the Code 45.
2. I learned that putting in new plugs gapped to just under 0.060 inches improved all of my issues other than the Code 45.
3. I learned that an engine with an automatic transmission has to be timed while the trans is in Drive.
4. I learned that my e-brake isn't strong enough to hold the car at idle in drive (which I think it should be).
5. I learned that lifting the rear of the car to keep it from running away while in drive with the e-brake on only makes the wheels drive harder without the resistance of the weight of the car trying to hold it back.
6. I learned the best way to time a car in this situation was to find a curb that was low enough to drive the front wheels up to without hitting the front fascia and let the car rest against it while working.
7. I learned that 9 degrees before top dead center works better than 11 degrees before top dead center when the plugs have a wider than recommended gap.
8. I learned that the automatic transaxle can make you think you have engine problems such as hesitation if it doesn't downshift correctly.
9. I learned that if you think you have an engine problem that is causing hesitation, it could be your trans and the way to test that is to shift through the Auto gears like a manual. If you have no hesitation, it isn't the engine.
10. Here's a BIG ONE: I learned that if you don't know squat about automatic transmissions and you believe it isn't shifting correctly, put half a can of Sea Foam Trans Tune in it! I can't recommend this stuff highly enough. In under five miles, I felt like I was seeing improvements in all my problems except the Code 45. By the fifteen-mile mark, all of the problems except for the Code 45 were so minimal that if the car had been operating like this in the beginning, I might have driven it like this and never thought anything other than "this is the best an old car can do".

At that point, when I really could have lived with the way the car was performing, I still had the Code 45. So I thought to myself, if the O2 Sensor is telling the ECM that there is a rich fuel condition, the ECM will respond by leaning the fuel delivery. Maybe that subsequent leaning of the fuel was the reason I still had a very slight hesitation. The test was to stop the "rich fuel" message from being sent to the ECM. That is easy enough. If the message is coming from the O2 Sensor, disable it so it can't send that message anymore. So I unplugged it and went for a drive. When I say it drove like a new car, I don't mean it drove like a DIFFERENT car, I mean it drove like a BRAND NEW car! It had torque and power in all the right places and it worked as well as a 2.8 possibly could. I didn't have a Code 45 any longer, it was replaced by a Code 13 which means an open circuit to the O2. Thereby confirming that the O2 was bad and it was effecting the car's performance negatively.

(performance) CASE CLOSED!!

Now for the bad news:
I have to take the engine out again and separate it from the trans again. Guess why? Now I have a bad oil leak at the rear main seal. I had changed the FRONT main seal before putting this engine on the cradle. I actually looked at the rear seal and thought to myself, "maybe I should change it too while everything is accessable?...NAAAAHHHH!!!" It had had a bad leak at the distributor when it was running in my other car. I rebuilt the distributor at that time and solved the leak. I don't know if the oil I saw after that was from the rear main seal or if it had come from the distributor and was working its way down and out. So, if if had a leak before, I didn't know. Could it be a result of sitting and not being used then having Sea Foam run though the crankcase oil? Maybe. I'll never know the answer to that and I don't really care. My car is fun to drive again and since I put all the bolts back in with anti-sieze, it should come back out without much fuss the next time. I guess that will be my big project as soon as this semester is done!

Jonathan

[This message has been edited by Boostdreamer (edited 10-27-2013).]

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Report this Post10-27-2013 12:07 PM Click Here to See the Profile for 92wastheyearClick Here to Email 92wastheyearSend a Private Message to 92wastheyearEdit/Delete MessageReply w/QuoteDirect Link to This Post
Now THAT is how you wrap up a thread!
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Report this Post10-27-2013 01:09 PM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by 92wastheyear:

Now THAT is how you wrap up a thread!


Almost! Had to go back and give everyone a + for particpation, even you! Thanks everyone for your help!

Jonathan

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Report this Post10-28-2013 07:41 AM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
Well, the story isn't over yet. I put the new O2 Sensor in and went driving. Guess what? No Code 45 Rich Fuel Condition but now I have a Code 44 LEAN Fuel Condition! What the crap?! Now I don't know if I wasted money on the O2 Sensor. Just as bad as the wasted money is the fact that the jumping/hesitation/bucking/backfiring thing is back!

I had decided that the bucking problem was with the transmission since it performed so much better after adding the Sea Foam Trans Tune. The problem was back so maybe the Trans Tune had dislodged some gunk that was clogging up the trans. I decided to change the tranny fluid. That was already on my list of things to do anyway and I had purchased the filter and gasket weeks ago. I checked on-line for Dextron fluid and found that Advance Auto had Castrol on sale cheaper than O'Reilly's store brand ATF. Got the big jug (gallon or 5-quart) for $15. I also had a quart-and-a-half in singles left over from topping off the trans after the engine swap.

It was my first time changing Auto trans fluid. I had read the many horror stories about the mess, and time. I didn't think it was too terrible. I raised the rear of the car and used my torpedo level to check the orientation of the trans pan. I lifted the car enough so that the pan was not level but leaning down toward the front of the car. Then I went around the pan and broke each bolt free. Then I went to the point closest to the front of the car and began working my way to the rear removing bolts. All the fluid was directed toward the front of the pan and I used my normal round oil drain pan to catch it. Other than the light splattering off the solid top of the drain pan (hole in the center), it did a fine job of catching all the fluid. I didn't rush it. As long as it was flowing out in multiple streams, I let it drain. When it slowed down, I removed another bolt.

The visible part of the filter element was brown. I had never seen the ring in the pan before so when I looked at it, it looked like some kind of rubber donut. I put my finger on it and I discovered that the "rubber" was actually a thick layer of sludge that had collected on a circular magnet! Crazy! I got all of that cleaned off and wiped everything down. My new gasket was a little bent up from having been in the package. I let it sit in the sun while the oil drained but it wasn't flat by the time I needed it. I used a thin smearing of blue RTV on the pan side of the cork gasket to make it stick in place. AFTER I finished all that, I realized that the bolt holes in the gasket were interference-fit! By that, I mean that the bolts could push through the pan and gasket and they were snug in the holes. I was able to put all the bolts back in the pan and let the gasket hold them in place while I got them started back in their holes. Looks like I didn't need to do the RTV afterall. All the bolts looked to be the same to me but I believe I got them all back in their original holes.

I torqued the bolts in as close of a star pattern as I could come up with. I used 96 inch-pounds as per the Haynes manual. I don't think they were that tight before I loosened them so I have a sliver of hope that the oil I have been seeing on everything is actually ATF (which was brown by the way). It would be really nice if it turned out that the rear main seal was still in tact. It took all the ATF I had on hand to fill the trans back up. I just got it over-filled a little bit. I'll have to fix that today. Went driving. Problem not solved. Still bucking, still code 44. The odd thing is that if I move the gear selector to 2 when it starts bucking, it stops! Go figure!

Anyway, it must not be the trans. Here is my list of possibles:
1. Water in the gas
2. Bad MAP Sensor
3. Bad injector(s)
4. Leaking pulsator or rubber hose that connects the fuel pump to the fuel sending unit.

I guess the first thing on the list will be to hook up the fuel pressure gauge again and see if I have a leak-down problem and to see what the running pressure is. Next, I'll start swapping MAP sensors again. Not that I think this is the problem or the solution, but I can't do much else before I burn off some fuel. That's because I have a super clean 88 tank with a new fuel pump sitting on my carport. I'll run the fuel down to about a quarter tank or so and swap the tanks out. That will give me the larger fuel capacity AND eliminate the pump and connecting hose as possible problems. Then I'l go fill up and add some Heet or Sea Foam to the gas just in case there is any water. If none of that helps, that will leave the injectors.

Jonathan
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Report this Post10-28-2013 09:23 AM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
I thought about swapping ECM's but I discovered that the 85-88 2.8 V6 ECM's are the same. I also learned that not only do you need a transmission-specific PROM, you need one from the same year as the ECM (theoretically speaking of course; some have posted success mixing ECM and PROM years). Anyway, no need to put in the 88 ECM yet (it would be hard to imagine that the ECM is the problem).

Jonathan
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Report this Post10-28-2013 12:30 PM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
I definately have a fuel pressure problem.

I put the gauge on and with one turn of the key, engine off, I had 42 psi.
Started the car, had a constant 45 psi including when revving the engine.

Turned car off, pressure was 42 psi. In under five minutes, the pressure had bled off to below 20 psi.

No need to mess with MAP sensors at this point! Gotta be an injector or an in-tank problem. I just disconnected my O2 so I can do my running without the jumping and bucking. That will get me through the next two days of driving. Maybe I'll try to swap tanks tonight.

Jonathan
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Report this Post10-28-2013 05:26 PM Click Here to See the Profile for MarkSClick Here to Email MarkSSend a Private Message to MarkSEdit/Delete MessageReply w/QuoteDirect Link to This Post
Sorry to hear the O2 sensor was not the problem. Still, when re-connecting the O2 sensor, the engine will try to go into close loop operation and that's when the issues reappear. Still could be electrical problems somewhere.

BR's,

Mark
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Report this Post10-28-2013 09:34 PM Click Here to See the Profile for 92wastheyearClick Here to Email 92wastheyearSend a Private Message to 92wastheyearEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Boostdreamer:

I definately have a fuel pressure problem.

I put the gauge on and with one turn of the key, engine off, I had 42 psi.
Started the car, had a constant 45 psi including when revving the engine.

Turned car off, pressure was 42 psi. In under five minutes, the pressure had bled off to below 20 psi.

No need to mess with MAP sensors at this point! Gotta be an injector or an in-tank problem. I just disconnected my O2 so I can do my running without the jumping and bucking. That will get me through the next two days of driving. Maybe I'll try to swap tanks tonight.

Jonathan

Yeah for sure need to address that fuel pressure issue

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Report this Post10-29-2013 01:30 AM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
I put my 88 gas tank in. I've never had such a hard time with gas tanks before! Naturally! I could not get the front strap back on. I was thinking that the 88 straps were longer but they are actually SHORTER! In the end I had to wire it up out of the way as best as I could.

I got the tank in and got it started. Besides it being pretty much silent, I know nothing about the work I just did. Tomorrow (today) I'll have to drive it, check the pressure situation, and see if the gas gauge works. If all of that looks good, I'll connect the O2 again and see what happens.
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Report this Post10-29-2013 05:44 AM Click Here to See the Profile for RaydarClick Here to Email RaydarSend a Private Message to RaydarEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote

I put the gauge on and with one turn of the key, engine off, I had 42 psi.
Started the car, had a constant 45 psi including when revving the engine.

Turned car off, pressure was 42 psi. In under five minutes, the pressure had bled off to below 20 psi.


While it's not the ideal situation, I don't think that that slow of a bleed-down will cause driveability issues. Not like you are seeing.

Was the battery disconnected after you swapped O2 sensors? Just a thought. May not make a difference.

The code is for "lean", which means the ECM should be adding gas.
Do you smell raw gas? Is your exhaust black? If so, it's not running lean.

[This message has been edited by Raydar (edited 10-29-2013).]

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Report this Post10-29-2013 10:03 AM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
As long as the O2 is disconnected, it runs like a dream! Does have a strong exhaust smell though. While disconnected, I figure that the ECM is getting needed fuel info from the coolant sensor and the MAP. When the O2 is back in the mix, I think it correctly tells the ECM that there is a rich condition (caused by the injector stuck open). The ECM then tries to compensate for the one rich injector by starving them all. That's when I get the bucking and jerking. If I unplug the O2, it eliminates that struggle and just keeps the fuel available and like I said, drives like a dream.

Jonathan
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Report this Post10-29-2013 10:18 AM Click Here to See the Profile for RaydarClick Here to Email RaydarSend a Private Message to RaydarEdit/Delete MessageReply w/QuoteDirect Link to This Post
Ah, okay. That makes sense.
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Report this Post10-29-2013 12:40 PM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
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Originally posted by Raydar:

Ah, okay. That makes sense.


I hope so because it is 100% pure speculation!!

Jonathan

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Report this Post10-29-2013 05:44 PM Click Here to See the Profile for MarkSClick Here to Email MarkSSend a Private Message to MarkSEdit/Delete MessageReply w/QuoteDirect Link to This Post
Someone needs to put together a flow chart for diagnosing this type problem there are several out there now and no one cause apparently. If I was retired, I would; along finishing my 3.8 swap!

Anyway, my other Fiero had a miss which was eventually diagnosed to a fuel injector. Figured it out by unplugging one injector at a time. When I did a leak down test on the all injectors, the offending injector was the only one that wasn't leaking- sort of what your are theorizing now I think.

BR's,

Mark
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Report this Post10-29-2013 07:42 PM Click Here to See the Profile for RaydarClick Here to Email RaydarSend a Private Message to RaydarEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Boostdreamer:

I hope so because it is 100% pure speculation!!



It really does. I still wonder about a 2 minute leakdown causing the kind of rich condition you are seeing, but I can't say that it won't, either.

You still have a whole fuel rail and injectors from your other engine, I'm guessing.
If it was running okay (clattering noises notwithstanding) I would be inclined to just swap them in.
In order to do any testing, you're going to have to remove the fuel rail and injectors anyway.

Of course, you could send both sets off and have them cleaned and flow matched, if you wanted to. You should end up with six good ones and a few spares.

[This message has been edited by Raydar (edited 10-29-2013).]

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Report this Post10-29-2013 08:07 PM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by MarkS:

Anyway, my other Fiero had a miss which was eventually diagnosed to a fuel injector. Figured it out by unplugging one injector at a time. When I did a leak down test on the all injectors, the offending injector was the only one that wasn't leaking- sort of what your are theorizing now I think.

BR's,

Mark


Good tip. Thanks, I may have to resort to that.

Jonathan

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Report this Post10-29-2013 08:11 PM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post

Boostdreamer

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quote
Originally posted by Raydar:

You still have a whole fuel rail and injectors from your other engine, I'm guessing.
If it was running okay (clattering noises notwithstanding) I would be inclined to just swap them in.
In order to do any testing, you're going to have to remove the fuel rail and injectors anyway.


This is exactly what I'm going to do after class this afternoon. I have a third set also. Hope it doesn't come to that. I guess I should go check out my other fuel rail in the mean time and see what I can learn about it before I put it in.

Jonathan

[This message has been edited by Boostdreamer (edited 10-30-2013).]

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Report this Post10-30-2013 06:15 PM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
Class ran late, had to eat lunch late, got into the garage late. Not enough time to swap fuel rails in the daylight. My biggest worry was trying to get the big fat vacuum hose under the plenum re-attached. What I did accomplish was to check out my other fuel rail. I cleaned the injectors up a bit and pulled the electrical connectors off, one by one. I applied 9V to each injector and they all made the little clicking noise. I can only assume that they are working correctly. I thought about just putting these injectors on my other fuel rail since it looks nicer. I decided against that when I realized that my problem could be the fuel pressure regulator allowing fuel to flow into the vacuum hose. This way, I will eliminate the potential for BOTH problems at the same time. I'll get into this afer my last class tomorrow.

Jonathan
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Report this Post11-01-2013 07:49 AM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
I swapped fuel rails and plugged the O2 back in. Drives great. Still have an intermittant Code 44 Lean Fuel Condition but at least without any noticable effects in performance. I guess I can try swapping the MAP sensors again. Maybe it is going to take some time to "settle in"? I'll keep an eye on it and maybe have the engine fogged for vacuum leaks later.

At least I think this solved the Code 45 Rich Fuel Condition which I think was the BIG problem here.

Jonathan

[This message has been edited by Boostdreamer (edited 11-01-2013).]

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Report this Post11-01-2013 05:12 PM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
I finally ran through the tank of gas that I mixed the Sea Foam with. At least now I know that water in the tank is not a factor. Strike that off the list of possibles. Something else weird did happen when I filled up. When I took the gas cap off, there was a serious rush of air into the tank and it popped as it expanded. I had heard the tank creaking a few times but I thought it was just a bit loose since the front strap wouldn't fasten. Apparently, it was popping from getting sucked in from the fuel pump pushing the fuel out. That really says a lot for that little pump! That sucker must be really strong to fight against the vacuum it was creating while still pushing out 40 psi of gas! Pretty sure that one is a Delphi pump. I suppose I have a clogged vent line. I'll have to look into that tomorrow.

I wonder if that was going on before the tank swap? Wonder if it had anything to do with either of the many problems I have been fighting lately? I wonder if the lean fuel condition hesitation/bucking/backfiring thing was what caused the 86 engine to die? It was a pretty violent action when it happened. Maybe the 86 couldn't take it. I've heard the 87 engines were superior.

Jonathan
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Report this Post11-06-2013 10:22 AM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
In my recent engine swap, I changed out the exhaust manifold bolts for studs and nuts from The Fiero Store. Yesterday, I wondered if they had become loose, causing my Code 44. Sure enough several on the rear bank were loose enough to turn with my fingers! I don't understand why they had not vibrated all the way off but I'm very thankful that they did not. I used Never Seez on those studs so maybe the torque should be adjusted for that. I tried to get my torque wrench in there to tighten them up but there was no room to make it work. I ended up using a small combination wrench to snug them up. After about 60 miles of mixed driving, there is no sign of a Code 44! I'll have to check the front bank for the same thing and then periodically re-check them until I'm satisfied they will stay put. I'm also going to put a dab of high-temp RTV on the ends of the studs to make sure I don't ever loose the nuts by accident.

Solving the Code 44 has unfortunately had an undesireable side-effect. Now I have a constant Code 32 where before it was only intermittant. Two minutes down the road and the SES light comes on and stays on. I have been reading up on this issue and I'll be checking what I can to try to fix it. These threads are extremely informative:

http://www.fiero.nl/forum/Forum2/HTML/045528.html
http://www.fiero.nl/forum/Forum2/HTML/122507.html

On the bright side, the car is running like a champ even with the constant Code 32. I understand that that should come as no surprise. I have read that the Code 32 is the most common, the most difficult to eliminate, and has the least effect on the performance of the car. I guess if I have to have a constant code, it is best to have one that doesn't mess with drivability! Code 32 does, however, affect the economy. In one test of mine, it increased MPG by 3 on half a tank of gas. Your mileage may vary.

Jonathan

[This message has been edited by Boostdreamer (edited 12-02-2013).]

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Report this Post11-06-2013 11:06 AM Click Here to See the Profile for RaydarClick Here to Email RaydarSend a Private Message to RaydarEdit/Delete MessageReply w/QuoteDirect Link to This Post
Good save, on the exhaust bolts. Never would have pictured that.
Having said all that... The vacuum in your tank is likely a contributor to the code 44. It's possibly causing fuel starvation and/or lean running.
(Maybe it's not, but I certainly believe that it could.)
It may be what killed your other engine, too. Lean mixtures will tend to make cylinder temperatures run extremely high.
Could be why your valve or piston failed.

I would try running with the cap off, or at least a little bit loose, until you get your vent system working correctly.
See if it doesn't run even better.

Have fun with the Code 32. When I had it, the rubber ends on the vacuum lines were the cause. (Specifically, the elbow, where it plugs on to the throttle body fitting.) They didn't grip the plastic line any more.
About the time I installed the Trueleo, I just replaced all of the small hardline with rubber hoses.

[This message has been edited by Raydar (edited 11-06-2013).]

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