1992 3.l V6 T5 with 140,000 miles that is daily driver. Sometimes drive 200 – 300 miles in a day. Other times car may set for 2-3 days & always fires up and runs well. Been a reliable vehicle until now. Driving down the interstate at 70 mph when car engine cuts off & started coasting. Got it restarted several times until it finally coasted to a stop. Could start it and idle but would sputter & stall as soon as I tried to move it. Checked under hood & would idle, but sputter when I tried to open the throttle. Felt like it was not getting fuel when I pressed throttle. Left it overnight, until a mechanic buddy & I drove to out next day to try & fix it. Started right up and drove it back 50 miles to his house. Sputtered once or twice, but otherwise ran fine. The turn signals had been working off and on before break down. I noticed that they were working again after we started up car for drive back (could be coincidence). Once when it was sputtering while idling, he fiddled with wires around coil & it stopped sputtering. Made us think there is an electronic problem that happens only when engine is warm.

Distributor was rusty & shabby inside, so we replaced entire distributor with a rebuild. Same problem, starts and runs when cold; stalls when warm. Wait an hour and it starts and runs. Replaced coil & same thing. I researched the forum archives and told friend to replace wires from coil to distributor. He is also wondering if there is a fuel regulator or fuel pump issue. He called & told me he cannot find a port to hook up pressure gauge. He checked all around the plenum. Another mechanic told him some birds don’t have one. Don’t know myself ‘cus he is 30 minutes away & he has my transportation parked behind his house.

In last 10 – 12k miles, I replaced fuel filter, plugs, plug wires, O2 sensor, catalytic converter. I’m thinking either ECM or PROM, but will check fuel pressure first when I can get ride to his house to find fuel pressure port or figure out how to install one. He’s an old time mechanic who usually quickly finds the problem and hates to be stumped. I’m just a guy who tries to be a DIY on my Firebird.

Anything else we should be looking for? Thanks for any suggestions to help us get my baby running again.

 

Got a ride today over to my buddy & my car. Best day ever. Car still broke, but walked up to car, opened hood & put my finger on the shrader valve. He was shocked & embarrassed after telling me he couldn't find it & didn't think there was one on my car.

Car is getting worse & now barely idles. It started throwing off error codes 12 & 13. Again, it has a new O2 sensor installed 12 K ago. We checked fuel pressure &, at idle, was 40-42 psi. Pressure immediately went down to zero when we turn off engine.

Electric hatch had stopped working 3 weeks ago and now is working. Didn't think to check turn signals. Checked the pink wire going into new coil & it is running 12 volts. I'm still thinking ECM or PROM because of the funky and erratic electronics. We wiggled wires all over the place and it did not change idle sputter. Engine dies if we try to apply throttle. Mechanic buddy is now leaning my way. (He also kept grumbling all night about his not finding the fuel pressure port until I showed him.)

Anything else I should check before buying an ECM? Thanks!

 

Well fuel should not drop to zero when engine is shut off.it should hold and slowly bleed off, either the check valve is bad or an injector is leaking very bad.

One thing that killed me these last two weeks was a freaking injector, I pretty much rebuilt my distributer and ignition system, with no go. Ac output from alternator was a little high but still ran the same.i measured the injector loop on the six pin connector under the throttle body and one bank had 1.6 ohms to the 4 ohms on the other bank. I was going to take the plenum off and measure each injector but by that time I was in desperation mode and was talking over every possible diag path with my shop foreman(master tech) at work and he decided to come over and take a look.showed him everything I did, and shared ideas. I told him about the injectors and he began to disconnect injectors one by one. We disconnected #3 and engine started and idled fine was even able to open throttle and revv up, plugged injector back in and engine stalled before the clip even clicked. Replaced injector, cleaned throttle body and set timing.runs like nothing ever happened.

Try measuring injector resistance or just un plug one by one and see what happens.

 

If your fuel pressure is dropping when you turn the car off and is dropping quite fast. Check out the fuel pressure regulator diaphram, the injectors, and the in tank assembly. Somewhere its leaky by.

Have you put the fuel pressure guage on the car and been able to read it when you WOT???

If you measured the injectors one by one and there below 12 ohms when its close to room temp, toss those things in the trash. FYI our stock fuel injectors are garbage anyways. If you get different ones, contact southbay on here and get a good set.

 

Thanks. That was helpful. I thought I'd read somewhere that the fuel system should hold pressure for at least 20 minutes or more. Maybe my buddy is still right that it is a fuel system problem. If I have to replace one injector, I'll replace all. I've read several sites that advise the injectors are a weak point on this year and model.

Hope this is the answer. My mechanic friend is stumped and he hates that.

Again, thanks for the lead.

 

Starting right up when cold, after POS behavior when hot, is 100% consistent with a bad fuel pressure regulator valve.

Other things might cause the same behavior, but if you have a bad fuel pressure regulator valve, that is EXACTLY how it will act.

 

My 92 RS 3.1 Auto was doing about the same thing as your car, mine would idle fine, free rev good, start good, but once warm it would sputter bad when you gave it gas in gear, if you stayed on the gas it would stall. My fuel pressure was good and not bleeding off, but car still acting up. The shop I took it too ended up finding one of the plug wire boots was split at the plug and arcing bad and also the vac elbow to the fuel pressure reg was chewed in to spots-so 2 holes in it. The shop replaced the elbow and the wire and the car has never acted up since. I also did, new cap, rotor, plugs and wires and the car runs much better.

Now the odd thing to be is that your fuel PSI drops right down after the car is turned off-not good at all. I have a feeling an or some injectors might have crapped the bed, but don't overlook the FPR and other fuel system items. Yes the stock injectors are crap and Southbay injectors are the way to go from what I hear. If you order new injectors just get a set of 6. Also let them know you are a member on here and you get 10% off the order.

 

Which is VERY important, because you need a uniform spray pattern on all your injectors!
Don't replace just one, but all.

 

Thanks amlv20, fasteddi, W.E.G., & 2007xl50 for the great advice. This is the first time I checked the fuel pressure (had to buy gauge) so could not check at WOT. The pressure dropped to zero as soon as the engine was shut down. That surprised me.

I'm convinced it is the FPR or injectors or both, but may decide to put in a new set of injectors even if it is just the FPR since I'll have to remove the plenum anyway.

I forgot to mention that the tack stopped working and then started working. The screwy electrical stuff makes me think I also have an ECM that is going bad. I've found our old cars can have several unrelated things go wrong at the same time.

I've never been much of a mechanic, but I'm becoming a real expert on 1992 Firebird 3.1 vehicles. I especially appreciate the Third Gen forum which has provided me with many hours of reading entertainment :-)

 

From everything I've read here, our factory gauges are fairly hopeless for longevity, reliability, and accuracy.

If the tach is doing something stupid, its most likely just a dead/dying tach, and not likely related to any other part on the car unless the motor speed is matching the tach.

My '88 gauges need a serious makeover, but like you, I've got bigger fish to fry for the time-being.

I like your idea of doing BOTH the injectors and FPRV while you've got it apart. I don't like doing the same prep-work twice. If theose injectors and FPRV are all a quarter-century old, how much longer do you think either are going to perform correctly anyway?

Sometimes, if it aint broke, you've just been getting by with it. If GM wrote periodic maintenance/replacement like Mercedes, those parts would have been replaced several times already.

 

Mechanic buddy just called. He turned on key, but did not start car. Fuel pump did not turn on. But, when he started the car, the fuel pump turned on. It has a new fuel pump.

We discussed & think that the turn signal & fuel pump anomalies could be related to problem in steering column. But, other anomalies, erratic electric hatch & tach aren't. So, now we’re thinking fuel problem in FPR/injectors causing the ratty idle and bad ECM causing crazy electronics. Rebuilt ECM ($100) will be delivered tomorrow & I’ll pick up a new FPR. Buddy rightly insists we do one thing at a time until we find solution. Again, he hates to be stumped & is tenacious.

I’m not close to pushing car over a cliff, yet, but I’m too old, out of shape, & lazy to walk everywhere. Hope we get it going before everything in car is new and I've spent all my retirement money. On the other hand, if all the parts are new, it’s good for another 140,000 miles.

 

Did he have the fuel gauge connected? He would of seen fuel pressure.fuel pump does not need to run on every time the key is on. It turns on and primes for two seconds then shuts off, once engine starts the fuel pump will come on.it won't prime every time, if he would of cycled the key several times it would of primed. Is he listening for the pump or watching a gauge to see if its priming? As for the useless hatch pull down, it usually not electrically related if it is its just a switch or fuse.most of the time the plastic gear strips or the plastic body cracks. My tach did do the same thing days before my ECM went out, but you may have a tach signal dropping out. I always save replacing ECM as a last resort, they do go bad but not as often as other parts.i recently threw money at my car in despair to get my daily driver back.after I burned through 200 on rebuilding the ignition, I stepped back and tried a proper diag. Reading you already spent your retirement money, I'd hate for you to throw more money into it with out fixing it.

 

amlv20, the hatch now is working fine. It, turn signal, and tach are intermittent problems which make me suspect the ECM. If a fuse was blown, they would not work again until the fuse was replaced. I'm not saying I'm correct.

Yes, he had the gauge connected when he turned on engine, but just told me he did it only one time. He is picking me up today & we will double check. I don't mind paying for parts it needs or will soon need. Distributor was definitely trashed. New coil was wasted $30. But if I'd taken it to a shop, it would have cost much more. May not need injectors, but will soon, since they are original. I use Seafoam every now & then to try and keep them clean. Did find an FPR diaphram for less than $60 with shipping.

Should have the FPR & injectors tomorrow, Thursday. Again, thanks for the advice, I sincerely appreciate (and need) it. I'll update when we get it running and confess all my sins.

 

The tach, turn signal, and hatch issues have nothing to do with the ECM.

The engine cutting out while hot and/or under load is a classic symptom of the injector coils shorting out.

RBob.

 

THIS! Recently killed me.

 

Thanks for info on electrical. Put in new signal flasher & turn signal works find. Gave myself a dope slap for not thinking of flasher first.

Putting in FPR & new injectors tomorrow. Convinced it is bad FPR, but replacing crappy stock injectors before any go bad. Hope I don't have give myself any more dope slaps.

 

Please take pics and post during the disassembly/reassembly process.

 

What injectors did you get? Please tell me there not oem stock replacements.

 

I can tell you with 100% certainty that is WRONG. Explain the following using that strategy:
1. Wiring harness swapped along with ECM.
2. Old harness could run for days if necessary (with required fuel stops, of course).
3. All other parts UNCHANGED.
4. Random stalling when it feels like with replacement harness, when hot. NOT with old harness.

Again, wrong. First, accuracy: 25 year old gauges in my 87 were DEAD ON ACCURATE (except possibly the temp gauge which was pretty close). But, then, it was a Bird... Second, a jumping/inop tach is also an indicator of a problem in the ignition circuits, especially when accelerating with the engine hot. Ignition module is the first thing coming to mind (since I've had it happen personally).

OP, I'd bet you wasted money on replacing the ECM. Lack of troubleshooting tends to get people in money trouble (been there). I'm going to assume you've seen my posts on fuel pressure testing. But you didn't follow them to the T. So you may not have needed anything for the FPR, either.

First, the fuel pump relay fails a LOT more often than the ECM SHOULD. Should have swapped it with the one next to it before assuming the ECM is dead.
Second, if you have problems with a failing ECM, it didn't just die, it was murdered (like is commonly said about catalytic converters). High current due to shorted circuits is what usually kills solid-state circuitry by causing heat. Also could be a bad rectifier bridge in the alternator, bad ground, or any number of other things.
Third, code 12 isn't really a diagnostic code UNLESS there is a no-start condition (ECM not receiving reference pulses from ignition module).
Last, 91.5 and 92 model years used a different hatch motor assembly than previous years... May not be the motor if it's spontaneously working.

 

Mav knows his stuff so learn from he knowledge.

 

Fasteddi, I know about the high failure rate of OEM multi-tech injectors. I found a re-manufactured set of Python injectors.

W.E.G, just decided to drive GF to FL 'cus her brother is in intensive care. Mechanic buddy will install while I'm gone. Wish I could take pics & post to help others. I took pics of fuel pump install, but haven't posted yet 'cus I cut hole in floor & not in mood to see bitchin that I'm ghetto rigging & should spend 9-10 hours dropping axle & exhaust.

 

I had '92 with the same problem. Coolant temp sensor was bad.

 

Maverick H1L, thanks for info on fuel pump relay. Also, I've looked at my hatch motor and it just didn't seem to match what other's on this forum described. Now I know; different hatch assembly on my 1992.

 

I did the same when I changed over to a walbro 255 fuel pump. Cut a hole in the hatch area but when I put it back together. I mounted a piece of 1/4 inch stainless on there for a access cover. Sealed it up very well.

 

Notwithstanding the above admonishments, I can speak from experience when I say that replacement of a fuel pressure regulator valve solved the (what seemed like unsolvable - i.e. many hundreds $$$) problem with a 1994 Camry. It would start fine when cold. Would not start at all when hot. Replaced the FPR (after replacing damn near everything else under the hood), and the problem was gone. Whether this behavior carries-over to GM products, I cannot say from personal experience.

As for the gauges, all I can say is, "do a search." How many posts are there on this board about crapped-out gauges? ...and its not the gauges? ...its something else?

Maverick, I'm not trying to get into a pissing contest with you. Feel free to have the last word if you like. I try to avoid arguing on the internet. Its too much like trying to plan dinner by yelling through a drain pipe. Thank you very much though for sharing your experience and knowledge.

 

Buddy asked if he should change TCS while replacing FPR & injectors. I figured a $5 TCS for a 20 year old one, made good sense.

 

Hey, I almost forgot the most important part. Buddy called & held phone up to my smooth running engine. Whoopee!!!

Thanks guys for all your guidance. My buddy & I are 99% sure it was the FPR. But, buddy said it looked like one injector was starting to leak. Glad I spent the $$$ to replace all. He had trouble figuring out how to release bottom injector clips, but checked my Haynes book & found you have to turn them clockwise. (Got to get a real shop manual).

Fasteddi, I found all the info on this forum on how to cut access door for fuel pump & cover securely with metal plate, offset screws, & lots of silicone sealer. I suspect there are a lot of us on this forum who've done it.

Well, on to my next project; sound dampening with Lowe's "Peel & Seal" & installing new seats out of 1995 Firebird. I just hope the Third Generation gods don't strand me on the road again for a long time.

 

To answer the tach problem, yes, Maverick is dead on here. If your tach signal is dropping out and not reading, then you have a faulty ignition part. Your ignition coil being bad can cause it, but the car won't start. (Had an '84 Fiero that had that problem)

My '92 Camaro did the same thing, when the ignition control module went bad. It got so hot, the silicone grease had charred underneath it, but it didn't go until I opened up the throttle for hard acceleration(is that possible with only 140hp???)

When turning over the engine, the tach stayed at 0, and didn't even kick up for the RPM while cranking. Replaced my ICM and the car hasn't had a problem since.

*****Note***** If your distributor is stock, replace it. The stock units are know for faulty pickup coils(the ceramic coating cracks) and also they are known for the o-ring going bad.(Is your starter motor covered in a mixture of dirt/oil?)

A reman Autozone dizzy will come ready to install and carries a lifetime warranty. The pickup coil design is improved and the ICM is a high-quality unit. Just make sure that you do not pinch the wires to the ICM, the one that are inside the cap. I'm pretty sure that is what fried my ICM, the first time. No I didn't do the installation, because I don't know how to set the timing. A mechanic did the work and had overlooked the two exposed wires.

 

If my fuel pump fails, I'm scrapping my car. End of story. Then I'm driving to Detroit and finding the engineer, that was responsible for designing the fuel tank and placement. I'm, then, going to proceed the smack him, repeatedly, for his "excellent engineering design". Let's put it that way.....

 

3 words... External Fuel Pump.

 

Or fab up a nice, sealed up, trap door. Thats what I did. Not some hack job but a good planed out one.

What really helps is just getting a good fuel pump to begin with and never run it under 1/4 tank.

 

Get a door from a W-body (Grand Prix, Lumina, Cutlass Supreme, Regal) and use it as a template to make a hole and a reinforcement between the body and tank. The door is generally under the trunk rug behind the back seats.

 

I'll go with you to smack the engineer. Seriously, it was not that hard cutting an access hole. Used Bosch fuel pump. However, Bosch O ring was a little too large. Advance Auto gave me an OTC O ring that fit. Bosch brand has a good reputation, but probably ordered a million O rings from lowest Chinese bidder & Bosch didn't use any quality control over the rings.

There are other engineering problems with F bodies, such as need for a wonder bar so you don't tear out the steering box. Just part of being a Third Gen owner and making the mods to fix GM screw ups.

 

If you go with the stick-on sound insulation, be ABSOLUTELY SURE you have no water leaks into the cabin. When the floor turns funky from a water leak, you don't want to have to un-glue 107 soggy glued-on sound insulation sheets.

 

Lucky me. No cabin leaks so far!!!

 

My car will stall and sputter after like 30-40 miles of driving, it is fine in the morning when its cold and will get me to my destination, but as soon as I drive in the hot afternoon and try to get home, on average maybe 10 to 20 miles from home it will start sputtering and stall. I let it cool down for maybe 10 mins and I will get home.

From what I've been reading on this thread, I am going to change the fuel pressure regulator valve. I hope this works, if not I'm coming back to yall for more advice! this site is AWESOME!

 

You might want to check the fuel pressure before replacing anything. Also, I found Rock Auto had the lowest cost FPR. Good luck getting it running well again.