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Desperate help needed with 86 2.5L by Twilight Fenrir
Started on: 01-08-2015 09:27 PM
Replies: 43 (767 views)
Last post by: Twilight Fenrir on 02-01-2015 07:17 PM
Twilight Fenrir
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Report this Post01-08-2015 09:27 PM Click Here to See the Profile for Twilight FenrirSend a Private Message to Twilight FenrirEdit/Delete MessageReply w/QuoteDirect Link to This Post
I'm at my wits end with this one... And I apologize in advance for the novel this is probably going to turn into, I've been fighting with this for almost a month now, so I'm going to try to be thorough...

I have an '86 2.5L stock. A few weeks ago, it stopped starting, would crank but no ignition. After some poking about, the ignition control module was replaced, and the vehicle ran again for a week or so before failing to start again, same symptoms as before. I had the tach filter unplugged, with no bypass... but my tach mysteriously started working the day the car refused to start again.

Brought ICM back and had it tested, it passed.

Re-tested Pickup coil, and it failed, so I replaced it.

Went to time it, and battery was drained, found arcing through the large orange wire passing through the metal loop attached to the engine block right next to the battery, where all the engine wiring seems to pass through. Taped wires up, and insulated with a piece of rubber hose to prevent recurrence.

I now had ignition, and cylinders fired, but engine would not start.

Checked CTS, and MAP, both pass.

Engine mysteriously starts after a desperate bid of sitting and cranking to oblivion. Let it warm up, and timed it to spec under hood. Started and idled fine the next day, went into reverse, and first no problem. As soon as I hit it into second, engine bogged down, and stalled.

Started immediately there-after, and process repeated verbatim. Managed to limp it back the half mile I made it out of my drive way, right back where it left off.

Codes 33, and 45 were set. that's MAP sensor voltage, and Exhaust rich. Code 33 can set with engine missing, not necessarily due to faulty MAP, which could cause a rich condition in exhaust.

It has been bitter cold here, and after a bit of research, I found that moisture in the Distributor cap can cause these issues. It was snowing when I was doing work under the cap before, and we had some severe frost during a few nights I had it uncapped. So I took the cap off, and used my heat gun very carefully to dry out the cap, and the rotor. Making it just barely warm to the touch. (Which would instantly dry it off in sub zero temperatures)

Replaced cap, and engine started and idled smooth as silk. Let idle for 20 minutes or so, letting the engine get good and warm to dry out anything else that might be icy. Before taking it out for a test drive. To the exact same results as above.

Engine seemed fine through reverse and first, but once I hit 2nd, with my foot to the floor it wouldn't accelerate any longer. Managed to limp it back home once more to my driveway. Left it to idle, which was still smooth, until it stalled before I made it back to my house.

Engine will now no longer start again. No firing in the cylinders. I haven't checked for spark, it's too dark, and too cold out to be monkeying out there right now... There are no CURRENT codes, however the history shows 33, 34, 35, and 45. Of course, 33 and 34 are contradictory...

But, I'm beyond what knowledge I have at this point. I have no idea what to look at next, and my diesel truck is eating me out of house and home to keep it fueled to work and back each day. I'd actually take it to a mechanic at this point if I could...

Can anyone offer me a suggestion of what to check now? I'm completely lost...

Thanks for reading
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tebailey
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Report this Post01-08-2015 10:01 PM Click Here to See the Profile for tebaileyClick Here to Email tebaileySend a Private Message to tebaileyEdit/Delete MessageReply w/QuoteDirect Link to This Post
Without seeing it, I would check the fuel pump/filter.
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Patrick
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Report this Post01-08-2015 10:20 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by tebailey:

I would check the fuel pump/filter.


Yeah, low fuel pressure can give some strange symptoms. Get a fuel pressure tester on there and see what you've got.

[This message has been edited by Patrick (edited 01-08-2015).]

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theogre
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Report this Post01-09-2015 12:11 AM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Patrick:
Yeah, low fuel pressure can give some strange symptoms. Get a fuel pressure tester on there and see what you've got.

See my Cave, TBI Test Adaptor

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)


The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)

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Csjag
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Report this Post01-09-2015 07:26 AM Click Here to See the Profile for CsjagClick Here to Email CsjagSend a Private Message to CsjagEdit/Delete MessageReply w/QuoteDirect Link to This Post
I agree on the fuel pump but if that's not it check the ignition coil, Your old ICM may have been fine.
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Report this Post01-09-2015 11:01 AM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Csjag:
I agree on the fuel pump but if that's not it check the ignition coil, Your old ICM may have been fine.

bad coil or coil mounting can cause problems... Coil and ICM are ground thru their mounting hardware.
See my Cave, HE Ignition
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Twilight Fenrir
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Report this Post01-11-2015 02:11 PM Click Here to See the Profile for Twilight FenrirSend a Private Message to Twilight FenrirEdit/Delete MessageReply w/QuoteDirect Link to This Post
Sorry I'm a bit late getting back to here...

Got around to checking yesterday, and I'm without spark again. So, I can't check my fuel pressure at this time.

I tested my Ignition Coil per the service manual, and it checks out. I replaced it just a year or two ago, with a BWD part.

So, it seems all the components check out. New ICM, new Pickup Coil, Cap and Rotor were replaced last year, and don't appear to have any wear. Ignition coil checks out...

it's got to be the wiring, or the grounding somewhere then, right? I found the wiring schematic for the ignition system on page 8A-20-0 in my service manual.

It looks like the pink wire from the ignition switch brings power to the coil, which is shared with the ICM on the same connector, also pink. So, I guess I'll start with checking for power to the coil, then to the ICM... See about cleaning up the mounting hardware... but I'm not sure where to go from there.
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Report this Post01-11-2015 02:33 PM Click Here to See the Profile for Shho13Click Here to Email Shho13Send a Private Message to Shho13Edit/Delete MessageReply w/QuoteDirect Link to This Post
What brand ICM did you put in there when you replaced it? Most aftermarket ICM don't like the heat of the Fiero engine compartment.

Also make sure no corrosion is on the ICM mounting hardware, I believe it grounds through them.

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Twilight Fenrir
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Report this Post01-12-2015 08:24 AM Click Here to See the Profile for Twilight FenrirSend a Private Message to Twilight FenrirEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Shho13:

What brand ICM did you put in there when you replaced it? Most aftermarket ICM don't like the heat of the Fiero engine compartment.

Also make sure no corrosion is on the ICM mounting hardware, I believe it grounds through them.



I got the Master Pro... It was what O'Reilly's had on hand... I doubt heat is an issue at the moment. I'm in Northern MN, it's been -20F since this problem started...

Everything was nice and shiney when I put it in, minus the thermal paste :P
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Report this Post01-12-2015 09:03 AM Click Here to See the Profile for CsjagClick Here to Email CsjagSend a Private Message to CsjagEdit/Delete MessageReply w/QuoteDirect Link to This Post
Have you checked the connectors and wires on the pickup coil, they sometimes get loose or corroded. Also check to make sure the wires to the pickup coil aren't pinched by the distributer cap.
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Report this Post01-12-2015 10:31 AM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
Check fuel pressure by using 12V to ALDL pin G.
FP draws 7-8 amps so make sure you have good connections etc or you can get low power and low pressure because of this.

Coil Power goes thru C500. Make sure the coil have good power and ground.
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Report this Post01-12-2015 12:15 PM Click Here to See the Profile for Twilight FenrirSend a Private Message to Twilight FenrirEdit/Delete MessageReply w/QuoteDirect Link to This Post
I replaced the pickup coil, so new wires, and new connector. I took special care not to pinch the wires, as I have done so in the past..

The pink, and yellow wires coming into the ignition coil, out of the coil, and into the distributor all show full voltage, so there's power to the system...

While removing the pickup coil... There was a small ring of a magnet under the.... StarGate-looking steel ring. It was cracked in several places, but I shoved it all back together and bolted it in place... Thqt shouldn't cause an issue, right? Not sure what it does, but the magnetic field is still there...

Thanks Ogre about the fuel pump. Will do so when I can.

[This message has been edited by Twilight Fenrir (edited 01-12-2015).]

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tebailey
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Report this Post01-12-2015 12:37 PM Click Here to See the Profile for tebaileyClick Here to Email tebaileySend a Private Message to tebaileyEdit/Delete MessageReply w/QuoteDirect Link to This Post
Cracked magnets are not good, a crack will change and disrupt the magnetic fields. Replace it.
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Report this Post01-12-2015 01:45 PM Click Here to See the Profile for schallisClick Here to Email schallisSend a Private Message to schallisEdit/Delete MessageReply w/QuoteDirect Link to This Post
Forgive me if this has been ruled out already. I had an issue nearly identical to this a while back. Had spark and fuel but wouldn't start. I was so sure it was the fuel pump or circuit because I still have the problem with the relay circuit where I have to wait for oil pressure before It will start which sent me in the wrong direction. I was scratching my head over it for a while. Anyway, what I discovered was that the smaller positive lead connecting to the battery, not the heavy gauge one, but the smaller wire that bolts to the top of it, had corroded quite badly. I mean, why wouldn't it? The battery gets rained on all the time with that open vent thing right above it. I digress. I brushed the connections thoroughly and now it starts reliably every time(once I build oil pressure). Before I did this I could crank on and off for several minutes and sometimes it would start, sometimes not. I am not entirely sure what that lead goes to, I never checked since it was fixed, but cleaning it up fixed me in a snap.


Sorry if this is very layperson and you are well beyond this point in troubleshooting. Sometimes its the simple things you assume are fine.

Cheers!

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I drive a Fiero, too!

It goes vroom! Well, kinda.

[This message has been edited by schallis (edited 01-12-2015).]

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Twilight Fenrir
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Report this Post01-27-2015 05:48 PM Click Here to See the Profile for Twilight FenrirSend a Private Message to Twilight FenrirEdit/Delete MessageReply w/QuoteDirect Link to This Post
Alright, it's been a bit of time getting everything together...

I got my car running again by completely swapping out the distributor. I had so many things jerry rigged by the time I was done with the original, it would have been a pain in the future to replace my cap. And I never would have been confident driving it...

It's still not drivable, however. It starts every time, it idles great. I can get it going down the road. But once the engine hits 2000 RPM's, it basically flatlines. No further acceleration is possible. In 5th gear, I top out at 50 MPH. Taking foot off the pedal from this point either kills the engine, or very nearly does.

My fuel pressure test kit came yesterday, and I just got to go out there to check it today. With the key in the ignition, my pressure was at 9, with the car running it is at 12. So I should be good at that end. I had replaced the fuel filter just the other day (I had a new one laying around in my garage, so figured, what the heck!)

So to recap: I have an entirely new distributor, ICM, Pickup Coil, Rotor, Cap and all. New plugs and wires. New fuel filter. Fuel pressure is nominal. My car WILL fire up every time, immediately upon cranking the ignition now, and idles fine. However all power is lost in excess of 2K RPM. There are no ECM codes being set.

So... what does that leave me with? The fuel injector itself? Air in and out? And the ECM/wires/sensors?

thanks.

[This message has been edited by Twilight Fenrir (edited 01-27-2015).]

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Lou6t4gto
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Report this Post01-27-2015 06:57 PM Click Here to See the Profile for Lou6t4gtoClick Here to Email Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post
9 And 12 ??!! you found it, thats WAY to low. as soon as the engine picks up RPM and it needs more fuel , you're literally running Out of gas ! either the fuel pump, (you already put in a new filter) Or the "SOCK" in the gas tank is plugged with rust. what did the Old Fuel filter look like ? Did you cut it open to look for Rust ?
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Report this Post01-27-2015 07:04 PM Click Here to See the Profile for Lou6t4gtoClick Here to Email Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post
If the" injector" is "bad", it's Easy to SEE. Start it up with the air cleaner OFF, look right Below the injector, it Should be Spraying a nice "Cone shaped" spray. If it is "Dripping" at all, or the cone is not uniform all the way around, the injector is bad.(but I doubt it.)
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Twilight Fenrir
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Report this Post01-27-2015 07:17 PM Click Here to See the Profile for Twilight FenrirSend a Private Message to Twilight FenrirEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Lou6t4gto:

9 And 12 ??!! you found it, thats WAY to low. as soon as the engine picks up RPM and it needs more fuel , you're literally running Out of gas ! either the fuel pump, (you already put in a new filter) Or the "SOCK" in the gas tank is plugged with rust. what did the Old Fuel filter look like ? Did you cut it open to look for Rust ?


o.o No... that's spot on... according to my Service Manual, and the Ogre's Cave. 9-13 PSI is on-spec for the 2.5L TBI fuel system.

 
quote
Originally posted by Lou6t4gto:

If the" injector" is "bad", it's Easy to SEE. Start it up with the air cleaner OFF, look right Below the injector, it Should be Spraying a nice "Cone shaped" spray. If it is "Dripping" at all, or the cone is not uniform all the way around, the injector is bad.(but I doubt it.)


Yeah, I was looking at that before... it's uniform under certain throttle conditions... but not all of them. I was playing with the throttle lever and watching the spray pattern. IIRC, it looked a bit like a shotgun at idle, but turned into a cone when I pushed on the throttle lever... Buuut... my memory is a touch fuzzy, I'll have to go fiddle with it again to be sure that's how it went.

[This message has been edited by Twilight Fenrir (edited 01-27-2015).]

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Csjag
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Report this Post01-27-2015 07:34 PM Click Here to See the Profile for CsjagClick Here to Email CsjagSend a Private Message to CsjagEdit/Delete MessageReply w/QuoteDirect Link to This Post
Have you hooked up the aldi program to it, that would tell a lot about whats going on
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Report this Post01-27-2015 08:43 PM Click Here to See the Profile for fieromattyClick Here to Email fieromattySend a Private Message to fieromattyEdit/Delete MessageReply w/QuoteDirect Link to This Post
Which distributor do you have? Its the original one or a replacement.

I had trouble with a pickup coil in my distributor not to long ago. So i replaced it with a new one; however, the new one still gave me problems for some unknown reason. I finally gave up and replaced the whole distributor.... Problem fixed.

I got a brand new one for just over 100 bucks. I felt a lot better after it was in.

-Matt
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Patrick
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Report this Post01-27-2015 09:03 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Lou6t4gto:

9 And 12 ??!! you found it, thats WAY to low...


He's got a duke, not a 2.8 V6. The fuel pressure is fine.

 
quote
Originally posted by Twilight Fenrir:

It's still not drivable, however. It starts every time, it idles great. I can get it going down the road. But once the engine hits 2000 RPM's, it basically flatlines. No further acceleration is possible. In 5th gear, I top out at 50 MPH. Taking foot off the pedal from this point either kills the engine, or very nearly does.


These symptoms sound like a plugged cat. Temporarily take out the O2 sensor (to relieve exhaust pressure) and see if it revs higher.
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Twilight Fenrir
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Report this Post01-27-2015 10:03 PM Click Here to See the Profile for Twilight FenrirSend a Private Message to Twilight FenrirEdit/Delete MessageReply w/QuoteDirect Link to This Post
Can't tell you how glad I am that it's NOT the fuel pump... really didn't want to squeeze under there this time of year and drop the tank :P

 
quote
Originally posted by Patrick:

These symptoms sound like a plugged cat. Temporarily take out the O2 sensor (to relieve exhaust pressure) and see if it revs higher.


The cat is an empty can ^^; It still has the factory cat in it, and all the original catalyst is gone... But, I'll give it a try! I was wondering if a critter might have crawled in there... but that seems unlikely...

[This message has been edited by Twilight Fenrir (edited 01-27-2015).]

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Report this Post01-27-2015 10:30 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Twilight Fenrir:

It still has the factory cat in it, and all the original catalyst is gone...


Maybe it's all now plugging the muffler. But yeah, taking the O2 sensor out temporarily is easy enough, and it might tell you something.
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Twilight Fenrir
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Report this Post01-28-2015 09:26 PM Click Here to See the Profile for Twilight FenrirSend a Private Message to Twilight FenrirEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Patrick:

Maybe it's all now plugging the muffler. But yeah, taking the O2 sensor out temporarily is easy enough, and it might tell you something.


Well, it's been that way for at least the decade I've owned it ^^; So... kind of doubting it... Plus, the exhaust sounds normal. Wouldn't a blockage muffle the exhaust?

I'm back to thinking about my ignition system again... I'm really skeptical that multiple systems would fail simultaneously... I KNOW my ICM was fried the first time I had problems. I replaced it, the car ran great for a week, then crapped out to where it is now.

The only thing I HAVEN'T replaced this run, is my ignition coil. Which appears to be one of those black boxes there's just no way to definitively test without replacing it and seeing if it's fixed... Unless someone here knows a way?

Now... I replaced my plug wires, after I noticed the coil output was arcing to one of the smaller wires coming out of it. Wouldn't this send some tens of thousands of volts into the coil, only to be run through and amplified again? Likely frying the coil, and also a probable explanation for why the ICM blew in the first place, followed by the pickup coil?

But... I'm not sure... And I really can't afford to keep throwing parts at this until something sticks X_X My coil has a lifetime warranty. I could get it replaced. But I'd feel like an ass if replacing it didn't fix the problem.

I ran a multimeter across it... There's about 3 Mega-Ohm resistance between the +/- terminals and the frame. (Manual says it should be high, or infinite... that's pretty high) There's 10,400 ohm resistance between the +/- terminals and the output. I couldn't find any specifics for the Fiero coil ratings... Internet says generally it should be between 7,000 and 10,700 ohms... While the resistance between the other two terminals (Signal wires?) is .4 ohms. (Manual says it should be low or zero)
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Report this Post01-28-2015 10:47 PM Click Here to See the Profile for Twilight FenrirSend a Private Message to Twilight FenrirEdit/Delete MessageReply w/QuoteDirect Link to This Post
Well now... here's an interesting post I found in a completely unrelated thread about the V6 just randomly browsing while anxiously waiting for a reply...

 
quote
Originally posted by 85 SE VIN 9:

Could your gas tank filler be rusting through? This would mess up the vacuum. Does the gas overflow or leak when you fill to the top?


I've noticed a slight leak in my filler neck, making a very small puddle under my car while I was filling up recently.... But surely that wouldn't be this catastrophic? o.o

[This message has been edited by Twilight Fenrir (edited 01-28-2015).]

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Twilight Fenrir
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Report this Post01-29-2015 06:07 PM Click Here to See the Profile for Twilight FenrirSend a Private Message to Twilight FenrirEdit/Delete MessageReply w/QuoteDirect Link to This Post
Well, here's a new development!

Slapped in a new ignition coil, and took it out for a test drive... I got it up to 55, even 60, as long as I stuck in 3rd gear, my acceleration wasn't hampered. Hit 4th, and pfffft.....

But, that's not what's interesting....

What IS is, when I got home, I smelled something a little odd, and took a peak under my decklid... only to find my exhaust manifold GLOWING red >_> That's not normal.

I immediately ran a vacuum test, I get 20 at idle. Hitting the throttle makes it drop sharply, but it bouys back up to about 13 or so and stays there.

[This message has been edited by Twilight Fenrir (edited 01-29-2015).]

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DisplacementIsKing
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Report this Post01-29-2015 06:19 PM Click Here to See the Profile for DisplacementIsKingClick Here to Email DisplacementIsKingSend a Private Message to DisplacementIsKingEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
But, that's not what's interesting....

What IS is, when I got home, I smelled something a little odd, and took a peak under my decklid... only to find my exhaust manifold GLOWING red >_> That's not normal.


You may be running lean... Should not get that hot. Are you getting any codes? I am fighting a miss on acceleration and after 2500rpm ordered a new bosch fuel pump/strainer
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Report this Post01-29-2015 07:42 PM Click Here to See the Profile for Twilight FenrirSend a Private Message to Twilight FenrirEdit/Delete MessageReply w/QuoteDirect Link to This Post
Just got back from also running with the O2 sensor removed to test for exhaust blockage... I think it actually ran WORSE somehow... but maybe I was just terrified from the noise :P Either way, my manifold was still glowing after driving out only one mile, and coming back.

 
quote
Originally posted by DisplacementIsKing:


You may be running lean... Should not get that hot. Are you getting any codes? I am fighting a miss on acceleration and after 2500rpm ordered a new bosch fuel pump/strainer


I'm not getting any codes, anymore. I had a few pop up over the course of this nightmare though... one of which was the O2 sensor reading a rich condition. This was back when my engine was misfiring like mad due to some fault in my ignition system, which has since been repaired...

IIRC, a rich exhaust condition will fry an O2 sensor in pretty short order... So my sensor may be shot, leading to a lean or rich condition...

When I had my sensor out for the above test, there was a lot of metallic scale on the outer shell...

Now that I think about it... I believe I was in the same boat once before, way back when...

Luckily the O2 sensor IS interchangeable with my '84. So, tomorrow, I'll try prying it out of there and shoving it into my '86 and see how it goes.

[This message has been edited by Twilight Fenrir (edited 01-30-2015).]

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DisplacementIsKing
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Report this Post01-29-2015 09:54 PM Click Here to See the Profile for DisplacementIsKingClick Here to Email DisplacementIsKingSend a Private Message to DisplacementIsKingEdit/Delete MessageReply w/QuoteDirect Link to This Post
The car should run rough without the o2 since its not monitoring the fuel/air ratio... I cant see how the exhaust could be blocked enough to run bad. If the o2 were bad, it would bring up a code but a new one never hurts. I bought a bosch o2 sensor from rockauto for 12$. These 2.5L Iron Duke should be as simple as it gets but still manage to be a pain sometimes.
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DisplacementIsKing
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Report this Post01-30-2015 08:47 AM Click Here to See the Profile for DisplacementIsKingClick Here to Email DisplacementIsKingSend a Private Message to DisplacementIsKingEdit/Delete MessageReply w/QuoteDirect Link to This Post
Just thought of something, have you checked your timing?
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vette7584
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Report this Post01-30-2015 09:39 AM Click Here to See the Profile for vette7584Click Here to Email vette7584Send a Private Message to vette7584Edit/Delete MessageReply w/QuoteDirect Link to This Post
here is something to check. i ran into all the same issues you are describing, the red hot manifold is what sparked me to write you. all of your symptoms are the same as i had in my 86 duke, and if what i think it is, you wont like it. you need to do a compression test. ii lost compression in 2 cylinders. what had happened was the rings got stuck on 2 cylinders letting unburnt fuel pass by into the exhaust, causing the manifold to be cherry red. i bet this is your problem. mine would start, idle fine, but stumble when driving. i tore it down, and found the rings were stuck to the pistons. it seemed odd to me that this happened to my daily driver, but it did. cleaned all pistons, honed cylinders, new rod bearings and rings and i was back in business, this happened in December 2014, still running fine, but, i have a super nice low mileage 84, its a summer car only, well, after getting it out last spring, i noticed it exhibiting the same exact symptoms, did compression test, and same thing. do a compression test, i bet you will find something there. good luck!
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Twilight Fenrir
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Report this Post01-30-2015 10:34 AM Click Here to See the Profile for Twilight FenrirSend a Private Message to Twilight FenrirEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by DisplacementIsKing:

The car should run rough without the o2 since its not monitoring the fuel/air ratio... I cant see how the exhaust could be blocked enough to run bad. If the o2 were bad, it would bring up a code but a new one never hurts. I bought a bosch o2 sensor from rockauto for 12$. These 2.5L Iron Duke should be as simple as it gets but still manage to be a pain sometimes.


I know I burnt out an o2 sensor in the past with a rich condition... The code came up for rich condition right away, before disappearing when the sensor died. I think my manifold was glowing then, too, but that was quite a while ago and I don't remember that part for certain... But whatever havok it I had then went away when I put in a new sensor... Hopefully that will be the case when I can get to it tomorrow.

I'm half tempted to tear it all out and put in a carburetor and an analog distributor! :P

 
quote
Originally posted by vette7584:

here is something to check. i ran into all the same issues you are describing, the red hot manifold is what sparked me to write you. all of your symptoms are the same as i had in my 86 duke, and if what i think it is, you wont like it. you need to do a compression test. ii lost compression in 2 cylinders. what had happened was the rings got stuck on 2 cylinders letting unburnt fuel pass by into the exhaust, causing the manifold to be cherry red. i bet this is your problem. mine would start, idle fine, but stumble when driving. i tore it down, and found the rings were stuck to the pistons. it seemed odd to me that this happened to my daily driver, but it did. cleaned all pistons, honed cylinders, new rod bearings and rings and i was back in business, this happened in December 2014, still running fine, but, i have a super nice low mileage 84, its a summer car only, well, after getting it out last spring, i noticed it exhibiting the same exact symptoms, did compression test, and same thing. do a compression test, i bet you will find something there. good luck!


Rings got stuck? And let fuel into the exhaust? I don't understand what you mean... The piston rings would let fuel into the oil, not into the exhaust? Unless there are inserts around the exhaust valves, and that's what you are referring to?

I like that idea so very little I'm not going to consider it right now XD

I definitely appreciate the idea, and I'll check for that if my O2 sensor swap fails... But I'm not gonna think about it 'till that point :P Then I' ll have to start looking for a new Fiero...

For what it's worth... My engine isn't actually running rough... There's no missing, or back firing even when it stops accelerating... It just stops going faster o.o

[This message has been edited by Twilight Fenrir (edited 01-30-2015).]

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vette7584
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Report this Post01-30-2015 12:01 PM Click Here to See the Profile for vette7584Click Here to Email vette7584Send a Private Message to vette7584Edit/Delete MessageReply w/QuoteDirect Link to This Post
all the symptoms you are describing are exactly what i encountered, i changed all the same components as you. check the compression, its quick and easy, and will give you piece of mind, but i can tell you, i wouldnt be surprised if you got low readings on at least 2 cylinders. mine would idle fine, run fine and do exactly what you are describing. good luck.
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tebailey
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Report this Post01-30-2015 12:18 PM Click Here to See the Profile for tebaileyClick Here to Email tebaileySend a Private Message to tebaileyEdit/Delete MessageReply w/QuoteDirect Link to This Post
Swapped dist and red hot exhaust? Check your timing.
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Twilight Fenrir
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Report this Post01-30-2015 01:27 PM Click Here to See the Profile for Twilight FenrirSend a Private Message to Twilight FenrirEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by tebailey:

Swapped dist and red hot exhaust? Check your timing.


The cyl on the 'front' of the engine (where the belt is) is no. 1,right? I set timing to that, at least o.o
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Twilight Fenrir
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Report this Post01-31-2015 03:21 PM Click Here to See the Profile for Twilight FenrirSend a Private Message to Twilight FenrirEdit/Delete MessageReply w/QuoteDirect Link to This Post
Well... replaced my O2 sensor today... no change...

Compression is good, has 150+ on all 4 cyls. Thank god XD Not too shabby for almost 200K miles

While I had the engine running anyway, I ran a few other experiments. Blocked off the vacuum hose leading to my fuel tank, just in case it was being a vacuum leak: No change

Checked my timing, which is still spot on.

Then I pulled my air cleaner lid, and fiddled with the throttle and watched my injector... The spray seems even at idle. And if I ramp the throttle up sharply, it seems even as well... but if I just baaaarreeelly nudge the throttle, it starts making a loud hissing, and sputters a few times, at which point the engine will die of I don't either a) release the throttle to let it back to idle, or b) step on it, and rev the idle higher.

The sputters time perfectly with the near dying of the engine... Now, if the engine is dying, the fuel pump/injector don't care, and will just keep continuously spraying until the engine is dead, right? So, it is the sputtering causing the interruption of the engine, not the other way around? I re-performed the tests with my fuel pressure gauge in place, and no matter what the injector did, or how hard I pushed the throttle, the pressure never flinched. So, definitely not my fuel pump either... again... thank god :P

Here's a video I took, for good measure:

http://vid137.photobucket.c...4217_zps4yddcw32.mp4

In the video... it looks like the spray is cutting out while it's in idle, but it's not. Just a trick of light or something. It only starts to cut out when I lightly nudge the throttle.

[This message has been edited by Twilight Fenrir (edited 01-31-2015).]

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Lou6t4gto
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Report this Post01-31-2015 07:20 PM Click Here to See the Profile for Lou6t4gtoClick Here to Email Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post
In my book, That is Not a good spray, it looks like it's drowning it. are your spark plugs Black ?
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85 SE VIN 9
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Report this Post01-31-2015 07:31 PM Click Here to See the Profile for 85 SE VIN 9Click Here to Email 85 SE VIN 9Send a Private Message to 85 SE VIN 9Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Twilight Fenrir:

I'm not getting any codes, anymore. I had a few pop up over the course of this nightmare though... one of which was the O2 sensor reading a rich condition. This was back when my engine was misfiring like mad due to some fault in my ignition system, which has since been repaired...



From SM p 6E3-61 (for 2.8, but bet it's the same) "Inspect Oxygen sensor for silicon contamination from fuel, or use of improper RTV sealant. The sensor may have a white, powdery coating and result in a high but false signal voltage (rich exhaust indication). The ECM will then reduce the amount of fuel delivered to the engine, causing a severe driveability problem."

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Twilight Fenrir
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Report this Post01-31-2015 08:31 PM Click Here to See the Profile for Twilight FenrirSend a Private Message to Twilight FenrirEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Lou6t4gto:

In my book, That is Not a good spray, it looks like it's drowning it. are your spark plugs Black ?


They're more tan-ish, actually... So... should be good I suppose...

Why won't my car drive, damnit! T.T

[This message has been edited by Twilight Fenrir (edited 02-01-2015).]

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Twilight Fenrir
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Report this Post02-01-2015 05:14 PM Click Here to See the Profile for Twilight FenrirSend a Private Message to Twilight FenrirEdit/Delete MessageReply w/QuoteDirect Link to This Post
*BBBBZZZZZZTTTT* And, time's up... Drumroll please?

*dadadadaddadadadadadadaadad*
And the winner is....

IGNITION TIMING

Okay, yeah, some of you called that one way back when... but some idiot (me) forgot to disable the electronic advance... Jumpered the ALDL ports, timed it, and away I go....

Thank god that's over XD
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