First let me thank anybody that takes the time to actually read my attempt at describing the problems I'm having and what led to them.

I have had an 88GT for several years now. It is a bone stock 2.8 AFAIK. It has always started and ran great, with the occasional exception of some mild "bucking" at lower speeds when the throttle is held in one position. That was never much of a problem for me, as I don't drive it all that much, less than a thousand miles a year since I've had it.

At some point I noticed the CEL come on at highway speeds (65-70 cruising) every once in a while, but it never stayed on for more than a couple minutes, then went back out. I took the codes one day, surprise, 32, EGR. After eyeballing the system, found the EGR tube was just "hanging" below the manifold end, and then found that a blockoff plate had been installed at the manifold end. No changes anywhere else that I could identify. Like I said, it always started and ran great.

Since I don't drive it much, I kind of collected parts when I had the chance, for instance, came across a good EGR tube, and another EGR solenoid (supposed to be good) and bought a set of Rodney's SS vacuum lines.

So yesterday, I decided to change the plastic lines out for the SS and install the new tube and see what happens. BIG mistake it seems thus far. Can't get it to run much at all now. I've gone through the search function till I'm about cross eyed, read all the EGR threads including buddycraiggs excellant write up. Not found anybody that has stated having the exact same symptoms as I'm seeing, so am looking for help/advice/assitance from those who know more than I ever hope to about the sensors on the stock 2.8

With everything hooked up, it will start, begin to idle, then go up to about 2,500rpm for an instant, then drop down to below 500rpm, then usually die. Will start right back up again and go through the same routine. With the TPS unplugged, it will idle but stumbles when given throttle and just generally doesn't sound good, at least not like it did before I started this mess. The EGR valve DOES hold vacuum, i.e., the diaphram stays up when pushed there and the inlet blocked off.

The codes I'm getting now, (remember, it USED to be just a code 32 before I "fixed" it) are:

13-Oxygen sensor circuit Haynes manual says: Check for sticking or misadjusted TPS (which BTW is NON adjustable) check wiring and connectors from the O2 sensor, replace O2 sensor. ( Haven't done that, but remember, didn't have this code before the "fix")

22- TPS Haynes says: Check TPS adjustment (NON adjustable remember) Check ECM connector, replace TPS

32-EGR system Haynes says: The EGR solenoid should not be energized and vacuum should not pass to the EGR valve. The diagnostic switch should close at about 2 inches of vacuum. With vacuum applied, the switch should close. Replace the EGR valve.

33-MAP sensor Haynes says: Check the vacuum hoses from the MAP sensor. Check the electrical connections at the ECM. Replace MAP sensor. (All these things check out, and again, didn't have this code before "fix")

34-MAP sensor Haynes says: Code 34 will set when the signal voltage from the MAP sensor is too low. Instead the ECM will substitute a fixed MAP value and use the TPS to control fuel delivery. Replace the MAP sensor. (Remember, I'm getting a TPS code too.)

So........there it is. Maybe I haven't read enough of the threads already here in the search responses, I don't know, but I'm tempted to put the blockoff plate back in and see what that does, but I'm sure open to suggestions/things to check/change or otherwise fix my "fix".

If you've read this far, thanks and if you let me know, I'll put you down for a plus, help or not, I just appreciate being considered for input. If you should happen to hold the answer to my situation, I can still do no more than give you a plus, unless after your suggestion proves a fix, you want paid, which I will gladly do if you can remedy the problem long distance like!

Thanks for looking & HAGO!

[This message has been edited by Sage (edited 08-13-2012).]

Electrically unplug the MAP sensor. If the engine runs much much better then..........

Double check the vacuum line into the MAP sensor

Make sure you have vacuum at the MAP sensor connector with the engine running (Are you sure you have the vacuum lines run correctly)



Replace the MAP sensor if the upper two don't fix it but the engine still runs like crap with the MAP sensor connected.

-----

btw - the TPS won't make the engine run this bad.

A huge vacuum leak will only make the engine run faster at idle - so that's not it.

If somehow your EGR valve is open at idle that could cause this problem. You could try re-installing the block off to see if that 'fixes' the idle. If that corrects the problem then look at why your EGR valve is open at idle. (The ECM will NOT call for the EGR valve to be open at idle)

Your O2 sensor is not used when the engine is cold, so if you are having problems that are right from start up, then it can't be a bad O2 sensor.

[This message has been edited by phonedawgz (edited 08-13-2012).]

Disconnecting the electrical connector to the MAP let the idle go up over 2,000rpm and stay there. Plugging it back in brings it back down. As far as I can tell, there is vacuum to the MAP, and again, as far as I know, the lines are connected exactly the way the plastic lines were. I changed them one at a time, in hopes of avoiding mixing any of them up. Unplugging the electric to the TPS seems to be the only thing I've done thus far that brings it anywhere close to "normal", but it doesn't yield a good throttle response, i.e., it starts breaking up at the top of the curve. It never did that before.

I thought the same thing concerning the O2 sensor, but it does look like the factory original in there! Just never had a problem with it in the past, no codes for it or anything.

I do have some confusion concerning the vacuum lines that go into the metal lines mounted on the rear trunk wall. One of them goes to the vertical "canister" behind the air cleaner box, and the other, as far as I can tell, goes to the horizontal "coffee can" for the cruise control. This one is the one that concerns me. Is it supposed to go to the cruise control can, it looks to me like in the diagrams I've found, that both lines should end up in the charcoal canister behind the air cleaner box.

It's probably note worthy also that when I had the dist. cap off, I was surprised that the car ran at all, let alone as good as it did. The contacts in the cap were encrusted with white crap, and allot of dirt, rust on the contact arms in the dist. and just generally in disgusting condition. Since it didn't seem to affect runability before, I just basically cleaned it all up for now, blew all the crud out and put it back together that way, with the intention of getting a new cap and rotor after I saw what changes the new lines and EGR stuff made. Ooooboy! Thing is, when it's not stumbling and hunting all over the place, it sound like it's hitting on all 6 cylinders, so I don't believe the cap and rotor or the dist., even though in rough shape, are a huge factor in the problem I'm trying to deal with.

Thanks for your response PD, I shouldv'e known you would lend an ear and a helping hand. I've noticed how helpfull you always are to everybody. +for you for your input and taking the time to help.

Maybe the next step should be going back to the blockoff plate.

[This message has been edited by Sage (edited 08-13-2012).]

If unplugging the MAP sensor makes the idle go up, then there is a problem with the MAP system (not necessarily sensor) Unplug the electrical and then start the engine and see if at idle that the vacuum line sucks itself tight to your finger. It should not be weak.

2000 RPM is not unusaual for idle right after the ECM reset (disconnecting the battery). Does the idle come down after a while?

With the MAP sensor unplugged, jumper A-B and turn the key on but don't start the engine. Wait 30 seconds and then unplug the IAC valve. During that time the ECM would have been trying to close down the IAC valve. Unplugging the IAC then freezes it fully closed. Then start the engine. You might need to use the throttle to get the engine to start. How fast is the engine idling then? Less than 900 RPM? Then you don't have a vacuum leak causing this fast idle. More than 1000 RPM then you need to look for a vacuum leak.

If it is over 1000 RPM yeah then I would look at installing that block off plate.

[This message has been edited by phonedawgz (edited 08-13-2012).]

After clearing the codes, and starting the engine cold, everything plugged in, the only code that showed up after is 33, and the idle only does the racing to 2,500, then dropping to 500 on start up, then tries to stay at 500.

After performing your instructions above, with the MAP unplugged, A&B jumped, waiting 30sec. and umplugging the IAC, it goes to a steady 500-600 idle and will eventually die, with bad throttle response. Checking codes after this proceedure, yields the 33 as above with the addition of 34, so it seems to be something in the MAP circuit. I didn't feel much pull at all from the line going into the bottom of the MAP sensor, so maybe I need to pull the upper plenum back off and have a looksee. It looks like the other end of the line from the MAP is still plugged in where it goes, but the stainless lines don't seem to fit into the rubber ends near as tight as the plastic ones do, but "feel" like they should create a seal, not sure on that one.

Thanks again for working with me on this, I'd really like to get it straightened out before the coming weekend, as I was planning on taking the car on a 400 mile roundtrip Saturday. I have others I can drive, just was wanting to drive the GT a little before putting it away again for the winter.

Anyway, the last test did not produce the idle above 900, so that brings us back to "doh"

Yeah sounds like you have bad vacuum to the MAP. You could run a short line right from the manifold teat right there directly to the MAP. My guess is that it will run fairly well then with the MAP electrically plugged in.

The MAP sensor along with the engine RPMs is the main way the ECM decides how much fuel to inject. So if the MAP sensor was not connected to vacuum for example, the ECM will think the throttle is wide open and will inject all kinds of fuel into the cylinders. If the other end of the vacuum line that T's with the MAP sensor is open, the ECM will get a reading from the MAP that indicates the throttle is fairly open during idle, and will be injecting way too much fuel.

btw the other end of the T that feeds the MAP sensor is the fuel pressure regulator. One more thing to check. Sometimes the diaphragm in the FPR goes bad, and fuel under pressure enters the vacuum line. Unlikely but when you are running the mainfold tap directly to the MAP also check to see if any fuel comes out of the other end of that T

[This message has been edited by phonedawgz (edited 08-13-2012).]

I'll try the direct line from the fpr to the MAP tomorrow, working outside and it started raining and it's dark....soooooo put it away for the night.

I did take it all back apart and everything is connected as it is supposed to be. Just don't think the SS lines seal as tight to the rubber ends as the plastic did. Not sure that's the problem, or what can be done about it if it is. I thought the SS lines were supposed to provide an improvement. Also put the blockoff plate back on with no change after reassembly. Still getting code 33 and 34. Starts ok, sits there for a moment, then races up to what might be wot, which as you explained, dumps a bunch of raw fuel into the cylinders, which also explains why it smells like raw fuel at the exhaust. Then when it comes back down, it tries to idle around 400-500rpm, and eventually would die, if not shut off. Just for s**ts and giggles, I'm going to put a new cap and rotor on it tomorrow and see if that makes any difference, but not holding out much hope for that, either way, it needs it.

I'll report back in tomorrow sometime and see if there's any more thoughts from folks who know this stuff! (phonedawgz )

Thanks again for all your help and taking the time to post your response and knowledge, it is appreciated!

HAGO!

Put new cap and rotor on, no major difference, which is what was expected. But it does run smoother when it will run. I'm guessing new plugs and wires wouldn't hurt any either, but first things first, have to get it right and reliable first.

Ran a vacuum line from another source to the MAP sensor, all seems fine, runs great in the driveway, but didn't take it out on the road. Idles around 1050 and smooth with good throttle response, all the way through to WOT. Also didn't notice any fuel coming from the original line to the MAP, so don't think there's any problem with the FPR. So all that seems to indicate that the problem is the vacuum source to the MAP, which is the new SS line coming from the FPR that Tee's right in front of the MAP sensor to the upper plenum, then runs via a "shorty" SS line to the rubber L connector going into the bottom of the MAP. So now the question is, what's wrong with that line and how can it be remedied? Also cleared the codes again, ran the engine with the temporary vacuum line hooked to the MAP, shut it down and reread the codes, nothing...no codes at all...everything fine...what's up with that?

Anyway, again am open to suggestions, as I really don't know what could be wrong with the line from the FPR. I used the same rubber ends on the new SS line that came off the original plastic line doing the same job, IOW, nothing is different except the addition of the SS line.

Looking for clues!

edit to add: Cleared codes again. Pushed, twisted and otherwise "tested" all the SS to rubber connections on the MAP sensor line, started it up, idled fine for a few seconds, got the raised rpm, up to about 1,800, then dropped to 500-600 and tried to stay there. Doesn't want to take throttle and will eventually die. Read codes again, 33 is the only one showing up. Previous to this, swapped the MAP sensor and got exactly the same results. Have since put the original back, as there was no problem with it before changing the vacuum lines. I'm as much at a loss for understanding as I was when I started. Got to be that vacuum line, but I can't really find anything obvious wrong with it.

HAGO!

edited AGAIN to add: Finally some progress to report. Took the last inch and half of the new SS line to the MAP sensor, the one that comes off the main part of it to a T which gets the vacuum from the intake and carries it on the long end to the FPR and on the other end leads to the "shorty" SS line with the rubber L fitting that provides vacuum to the MAP sensor out of the picture and replaced it with the plastic line originally on the engine. Instant cure! Starts good, idles fine, runs as good or better than it did before I started all of these "improvements" and has good/normal throttle response. Yep, that's all I did, took the new little SS line off, put the old plastic little line on, and it cleared up all the idling/running issues I have been trying to cure. Still not sure what to think of it, but that is the only change made that effected a cure. Maybe I'll play with it some more at a later date, but for now, it will get driven. Could be there just wasn't a seal happening between the old rubber and the new SS, or maybe the SS tube was pushed TOO far into the rubber fitting, which in effect closed off the vacuum in the tube, maybe some grease or a wrap of tape on the end of the SS tube would provide the needed seal, I don't know, but it works now and I ain't gonna mess with it further at the moment! This whole experience has only served to reinforce an old favorite saying of mine...."if it ain't broke..don't fix it!"

After getting it running, took it out on the interstate and drove around 15 miles round trip with no problems. Idles at about 1,000rpm, has good throttle response and pulls as strong or stronger (new cap & rotor?) than it did before I messed with it. SES light came on after about 5 minutes, then went out for about two minutes, then came back on and stayed on till I got home and parked it. Codes found are 13 (O2 sensor) and 32 (EGR which was expected after reinstalling the blockoff plate), so I will try replacing the O2 sensor and see what mysteries that'll provide! After looking at it, I can envision bugering up the threads in the bung and end up having to replace the exhaust tube, not that I'm dwelling on the negative or anything.......... it just looks like it doesn't really want to come out of there.

Anyway, thanks again phonedawgz for providing your expertise and helping to narrow down the problem.

That's the end of today's adventure. I'm sure there will be more in the future, this IS a 24 year old used car!

Thanks for looking & HAGO!

[This message has been edited by Sage (edited 08-14-2012).]

You can try a little silicon grease on the ends of lines with some zipties on rubber boots to get really good seals... Also maybe you got some little rips in boots while changing things, has happened to me before. If you experienced any bucking before maybe your TPS is having some problems... I know when mine went bad it threw codes for it, but it also had idle characteristics similar to yours plus bucking while driving occasionally and just weird throttle response. You can try capping the line going to the fuel pressure regulator, It will just make you run a little rich but you can isolate if you have a leak or FPR problem. You can also spray throttle body cleaner around your vacuum components with the engine running and if your idle changes you have found a leak.

Code 33 tells you that your map sensor is probably functioning electrically, but not receiving any vacuum when it should be, as if the vacuum feed line is disconnected. Maybe you do have a nasty vacuum leak somewhere. (?)

There is a short piece of 1/2" or so tube that goes from the back of the throttle body to the lower intake manifold. Is that intact? (idle air passage)

Did something get pinched between the middle and upper intake plenum when you installed it, causing a massive vacuum leak?

Is the EGR opening when you don't want it to? Try disconnecting the vacuum feed line to it and plug off the line. This should prevent it from opening at all.

I'm honestly betting it's going to wind up being something simple.

Got it fixed for the time being, or at least running good enough to drive it. Edited post above. You guys must have been responding while I was doing the editing.

Thanks for your input, and you both got +'s from me!

HAGO!

btw - Code 32

Indicates a problem with the EGR valve CONTROL circuit. That is the vacuum solenoid and vacuum switch over by the thermostat housing. Code 32 does not indicate a problem with the EGR valve itself, or the intake to EGR tube. The block off plate didn't cause the code 32.

How to fix the code 32?

Fixing the valve itself
https://www.fiero.nl/forum/Forum2/HTML/045528.html

Purchase a PROM programmed for no EGR/CODE 32
https://www.fiero.nl/forum/Forum4/HTML/062839.html
or
http://www.reddevilriver.com/Related_Products.html

phonedawgz: I kinda figured that, as that was the situation before I did anything. The assembly that I put on during this "repair" was supposed to be good, but I didn't personally test it, so being that it's over 20 years old, it is probably in about the same shape as the one I took off. It seems to run fine without the EGR system working, so I'll be looking at getting one of your EGR delete PROMS. Would you prefer we go to pm's for that, or can I just order off your site and still get the discount even though it's listed at $45.00? Thanks again for your help in getting this straightened out.

I have this special page set up for the sale

http://www.reddevilriver.co...elete_PROM_Sale.html

Thanks, put in the order.

HAGO!

If you are worried about the O2 sensor...



Get this at autozone! 6 bucks a can, read the directions good. When I first got it I just read freeze off like getting off frozen parts. But it's a double play on words, you spray the threads/joint/nut/bolt whatever it is for a good 30 seconds and the spray freezes the part and cracks the rust allowing the penetrant to get it. The second I started using it correctly it replaced PB blast and Deep Creep as my favorites for offing stuck bolts and things.

Zach

Thanks for the tip Zach. Never seen that before now. Kinda sounds like the direct opposite of "squelching" rusted parts/threads, where you heat with a torch till cherry red, then shoot cold water on it right away. Do this a few times and generally, you can take the bolt/nut/part (whatever) out with your fingers! Seen this work on exhaust parts where there seemed to be no hope of ever getting things separated. Used it to remove all the bolts/nuts on a D-9 dozers' rockguards. Took an entire afternoon, but they all came off without breaking a single one. I do have an "official" O2 sensor socket, which I'll try after squirting it up with blaster and getting the pipe good and hot, but if that doesn't get it, I'll be trying the stuff you posted above. Autozone is only about a mile from me, and that is where I'll be getting the new sensor.

Thanks for the input, already plussed you, or I'd give you another!

HAGO!

quote Originally posted by Sage: It has always started and ran great, with the occasional exception of some mild "bucking" at lower speeds when the throttle is held in one position. That was never much of a problem for me, as I don't drive it all that much, less than a thousand miles a year since I've had it.

My car does this BAD what causes it? Why cant I stop it? I've replaced the map sensor and coil, plugs, wire, rotor, cap..... It still does it! My 86' doesn't but my 87' does!

Mitch:

I'm probably not the best one to answer you, maybe phonedawgz or some of the guys who know this stuff forward and backwards will post a better answer for you but..........since I've changed the vacuum lines and got the bugs worked out of mine, which turned out to be purely vacuum related, I've not noticed that particular problem. Based on that experience and observation, I would guess you should probably look at all your vacuum connections, in particular, the MAP sensor connection, or the MAP sensor itself. Do like was suggested to me, spray some starting fluid or penetrating oil or something around the intake manifold and all vacuum fittings, connections. Take note of any changes in idle, does it smooth out or raise or lower the idle speed? Has your SES light come on? Have you checked to see if any codes are stored?

Have you checked the timeing, the motor mounts and the dogbone?

It seems to be a game of hunt and peck, you know like the doctors play. You give em' your symptoms, they run some tests, if they find something, they prescribe a treatment/cure, if they don't, they do more tests. Process of elimination I guess. I've tried to give you my experience, so like I said, give it a little time and maybe one of the experienced techs will chime in with some bonified advice.

HAGO!

[This message has been edited by Sage (edited 08-16-2012).]

Just a little update to this saga.

Happy to report that I just drove 400 miles round trip without so much as a hic-cup from the engine! Was a joy to drive in the running aspect. However............did discover a new totally unrelated problem. Discovered a leak somewhere in/around the 5spd tranny (getrag) that spews gear oil while at highway speeds (65-75mph) after things get "warmed up". Thought it was the axle seals at first, then upon closer inspection, it appears to be coming out around the VSS, as far as I can tell. Plan at the moment is to clean everyhing up as much as possible, fill the tranny and drive it to observe where the stuff's coming from. Anybody know if there is thread sealer/tape used on the threads of the VSS, and should there be if not? I suspect the sensor, cause that's where it seems to be the "wettest". Everything else that's covered has dirt/dust mixed in with it and feels "gritty" and somewhat dry compared to right around the sensor, which is wet and slippery. Didn't completly empty the trans, but back bumper on drivers side is covered with tiny specs of fluid, that ordinarily I would take for oil, but the oil level never changed, and the viscosity of the specs is thicker than motor oil to me. Who's had experience with the VSS and leakage? Open to advice-suggestions.

Oh, and footnote, those low profile tires with the directional thread on them made from a compound for banked curves, are NOT acceptable for state/county maintained pot-hole ridden, seam sticking up blacktop roads! NEVER have I had a worse ride in my life! It was like riding on the rims...seriously...I had not driven the car farther than 20-25 miles right around home previous to this trip and after changing to these tires. My take on these tires.....DON'T DO IT! Great for a track and curves on a smooth road, but for everyday driving.......worst I've ever experienced. Was like riding in a buckboard wagon. There were times I thought the wheel was gonna come out of my hands and somebody had smacked the underside of my seat with a sledge hammer! Did I mention it was a bad ride?

If anybody has thoughts/suggestions on the speed sensor, I'd like to hear em'. Also, what do ya'll use in the gear box, 80/90w.?


HAGO!

Do not use gear oil in the tranny. Use Synchromesh by Pennzoil, Amsoil, Royal Purple and others. It is a lot 'thinner' than what you would think but it is exactly what you should use.

The VSS uses an O-ring. It is held in somewhat like a distributor shaft. When you pull it out be VERY careful not to drop the plastic gear off of it. It can be impossible to fish out of the transmission if you do.

+1 on NEVER use gear oil in your Getrag.

Thanks for the replies/advice, I'll get some syncromesh. Does anybody carry the O ring for the sensor by name? That is, can you ask for a VSS O ring and they'll have a listing for it or know what you're talking about, or is it just find the right size O ring by taking the old one in for comparison?

I know they sell the dist. O ring specifically as an O ring for the dist. cause I've replaced them before, but is the VSS O ring the same way or not? TIA. Sounds like a dumb question even to me, but I'm just trying to utilize the experience of those who have been there done that and maybe save myself some time.

Also, PD, my new PROM came Saturday, (I was out of town), thanks for the speedy service. Haven't installed it yet, as there is somewhat of a "strange" situation concerning that CEL: on my way to where I was going, the CEL came on shortly after everything came up to running temp and stayed on the remainder of the "up" trip, as was expected. But, after I got where I was going, and did some short distance running in town, it never came on again, AND on the trip back, which was later at night and cooler ambient temps, it still never came back on, and after having been here all day and driven the car short in town distances again, still no CEL. Not sure what to make of that. Haven't rechecked the codes, but they haven't been cleared, so I'm fairly certain it will still have stored at the very least, the code 32, but would have to confirm that with another code check. Any thoughts on this situation?

HAGO!

Went looking for a 5spd getrag, VSS specific O-ring, and there is no seperate listing for one that I found. Got a listing for the complete VSS-$50.00, comes with the new O-ring on it, but from what I've found so far, you are left trying to match a replacement to the old one. Just following up on my earlier posting in case anybody's researching the same/similar problem.

Would still like to hear input from those who know more about this stuff than I do about why the CEL, in particular, the code 32 for EGR doesn't get tripped everytime the car is driven.

HAGO!