88gta_hiflyer

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My car did not want to start this morning. It's not uncommon for it to take a second or two of cranking before it stumbles for a second and then fires right up and runs and idles great. That is because of my leaking injectors which I plan to replace. However, today it absolutely would not start unless I gave it gas. It started and stalled 5 or 6 times before I finally got it running. It wouldn't idle unless I kept my foot on the pedal but then it eventually idled on it's own. When it finally did idle on its own it was idleing at about 500rpm (usually 700-800) and felt like it was about to die the whole time. I was able to drive it around the block but it definately didn't feel right, idled way too low and lacked power.

This seems like a fuel issue. All of the ignition components are new and I've never had a problem like this with the car. I can hear the fuel pump priming but haven't had a chance to test the fuel pressure yet.

The really weird thing is that the car was driven 12 hrs prior to me trying to start it today. It ran great, no problems. So whatever has happened happened while it was parked over the course of the last twelve hours. Is that how it usally happens when a fuel pump dies? Any other ideas of what would just die overnight on me?

Also, when I'm checking my fuel pressure tonight, how do I determine if I've got a weak fuel pump vs. a faulty regulator? Any other ideas of what to check or what might cause this sudden problem would be much appreciated. Thanks.

88gta_hiflyer

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Sound like a fuel pump?

92RSMoneypit

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I had a crappy fram fuel filter come apart inside and my car did the same thing change the filter first.

And don't get a fram i wouldn't take a fram if they wear given them away free.

88gta_hiflyer

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My fuel filter is fairly new but it was just the cheapo carquest brand filter so that is possible, hadn't really thought of that. Thanks for the reply.

88gta_hiflyer

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I'm going to rent a fuel pressure tester tonight and hook it up. I think my pressure is going to be low because very little fuel shoots out when I press the shrader valve while the fuel pump is priming. If my fuel pressure is low, how do I know if I've got a weak fuel pump or a bad fuel pressure regulator?

If anyone knows please help me out. I really don't have the money to just start replacing parts randomly.

Mr Froman

Do you think a bad 02 sensor could be the reason for the rough idle? or IAC valve? You can clean your IAC valve pretty easily.

88gta_hiflyer

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Update: I replaced the fuel filter and fuel pump. I have good pressure at the rail but I still have to keep my foot on the gas to keep the car running. After a few minutes it will idle poorly at about 500 rpm. Still seems like its starving for fuel.

My next step is replacing the injectors. I've got the runners and plenum off and plan to finish the swap asap.

I'm wondering if I have an injector stuck closed. It's just crazy that this problem came out of nowhere. Hopefully the new injectors will fix the problem but please keep the suggestions coming if there is anything I'm not thinking of. I'm getting married at the end of this month and really want to drive off in my GTA. I've got to get this thing running asap!

Mr Froman

Have you checked the plugs, wires, PCV, and timing? I would definitely check the IAC valve if you haven't already.

88gta_hiflyer

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Yes I have checked all of those things. This car ran perfectly the day before all this started. I pulled it into the driveway one night, turned the engine off, and the next morning it didn't want to start or run properly. That's what is so strange about it.

I'm about half way through the injector swap. Got all the old ones out last night and it definately needs injectors either way. They were the original multecs except for one which had been replaced. Yep that's right, someone did all the work for a complete injector swap to replace one!

Hopefully the new Bosch III's will take care of the problem but keep the suggestions coming. Thanks!

Mr Froman

Let me know how it works out for you

88gta_hiflyer

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Will do. Thanks for the replies. I haven't recieved much help with this issue otherwise so I do appreciate it.

KNBlazer

did you check the regulator?

88gta_hiflyer

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No I didn't. Should I take it apart to see if the diaphragm is damaged?

A bad regulator did cross my mind but I was thinking if the diaphragm broke it would have happened while I was driving, while the system was pressurized, but who knows.

88gta_hiflyer

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UPDATE: This problem is still going on. Here is what I have done so far.

Replaced fuel pump
replaced fuel filter
replaced fuel injectors
checked all fuses
checked for spark on all cylinders
switced out ignition module with a known working one
checked all vacuum lines and hoses
set tps voltage

I plan to remove the distributor cap tomorrow to check for problems there. I will also remove a spark plug to make sure they are not fouled. The car starts much faster now but misses all over the place and feels like it wants to run on 4 cylinders. It stall right away if I don't hold the throttle open.

What about the ESC module and the MAF sensor? The car will not run at all with the MAF unplugged (not sure if thats normal). The car is throwing NO codes.

What else should I check? Someone please help me out here. I'm running out of ideas.

Mr Froman

I think you should have a MAP sensor. And seriously, check the IAC valve if you haven't already. Mine looked like charcoal.

88gta_hiflyer

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No the 88 is a MAF setup. I removed and cleaned my IAC a couple months back but I'll take it out and check it again. I think I've got an extra ESC sensor that I'll plug in tomorrow to check that. What are the other possibilities?

Also, if my car won't run at all with the MAF unplugged is the MAF bad? I have no codes.

87WS6

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I had similar issues a few years ago on my 1987 Trans Am. It turned out to be a bad ECM. I threw in a new ECM and used the stock PROM and the problems disappeared over night. Before that I replaced the TPS, IAC, MAF, EGR, coil, spark plugs, wires, cap, rotor, and did a few other things I can't recall and after all was said and done it was just a bad ECM. I had this same problem here recently working on a friend's V6. It was running like crap and turned out to be the ECM once again. 20+ year old ECM's aren't the most reliable things in the world I guess. You can get one from O'Reily Auto Parts or the store of your choice. If it doesn't work simply take it back. If it does work return your old one for a refund of the core charge. I think they are roughly $90 or so after its all said and done.

Mr Froman

An ECM can just got bad like that? Are they just plug and play to replace? And doesn't that mean you are getting another ECM just as old?

88gta_hiflyer

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Thanks for the replies. I just replaced my cap and rotor (they were in worse shape than I thought). IAC is clean and I cleaned all the passages when I had the plenum off for the injectors swap.

I pulled a couple of the plugs and they were covered in carbon and wet with gas. Would that have to do with my previously leaking injectors? I checked my ignition timing a few weeks prior to this problem coming out of nowhere and it was dead on at 6*.

I'm thinking 87WS6 might be right about the ECM. It's crazy that this problem came out of nowhere and I've replaced just about everything I can think of. That is interesting that you had the same issue and it turned out to be the ECM. I think it's worth a try. When I replace it do I just take the PROM out of my old one, put it in the new one and plug in the connectors?

Thanks again for the help guys.

88gta_hiflyer

iTrader: (1)

What does that mean if my spark plugs are coated with carbon deposits and wet with gas? I'll try a new ECM anyway but is there another problem I should be looking into?

88gta_hiflyer

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Another Update: I replaced my ECM with a new one from O'reillys today. No change. The car starts right away every time but stalls immediately. It will run if I keep my foot on the throttle bud surges badly and misses.

I did notice the other day when I replaced the dist. cap and rotor that there was some rust under the cap. I guess I'll try replacing the distributor and see if that helps. What else could possibly be the problem here. Please help me out if you can. Thanks.

88gta_hiflyer

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shot in the dark here but could the VATS system have anything to do with this?

88gta_hiflyer

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PROBLEM FIXED: Turned out to be a bad MAF. Never threw a code and no change in idle when tapping on it. Put a new one in and it runs like a dream. Hope this helps someone else.

Mr Froman

Awesome. Sorry to hear that you had to spend all that money on other parts but at least you know you won't have to worry about them now. I'm still a little confused on the ECM thing though because doesn't getting another one leave you with an ECM that's just as old/likely to go bad

88gta_hiflyer

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Well the ECM that I bought at Oreilly's was remanufactured and came with a warranty. I looked inside it and I'm guessing that all they do is re-solder everything and spary the circuit board with some sort of protectant clear coat. I actually ended up taking it back to Oreilly's since mine was still good. I'm gonna take the distributor back today since my old one was still good. Wouldnt hurt to replace those things but I cant be throwing $100 bills at this thing lol.

I'm assuming what was happening was the car was running way rich and flooding. That explains the gas/carbon on the plugs and why it would run with the throttle open since it would pull enough air in to compensate for too much fuel.

Anyway thanks for all your help through this process.

87WS6

iTrader: (1)

Yes, they can just go bad like that. Any computer component can.

Yes, you use your stock PROM and put it in the "new" ECM. Then its pretty much plug and play.

Often surging is caused by a faulty EGR. This wasn't the case with your car but for future reference it seems quite common.

A bad MAF doesn't always throw a code for some reason.

Remanufactured ECMs are at least reconditioned/refurbished. They should be good for some time.

Glad it all worked out for you.

KNBlazer

I'd keep the distributor... it gets a lot of abuse.... this being a 20+ year old dizzy... might as well keep it... problems will arise in the future that will be related to your dizzy.. so if it's the original one keep it.. just my bucket of pennies... the pick up coil can crack and still work... all of a sudden one day it will leave your a** stranded somewhere... 6-8 years ago I replaced my pick up coil and gear, cuz it was recommended by a tech... he said generally it's best to just get a reman one...

88gta_hiflyer

iTrader: (1)

Yeah I noticed when I had the dist. out that it has already been replaced with a remanufactured unit at some point. It was the same one I bought. Looked like it was in decent shape except for the rust on top which I cleaned up with a wire brush. I threw a new cap and rotor on it and replaced the unreliable aftermarket ignition coil that comes with it with a GM one. The only thing I didn't replace was the pickup coil but if that goes I'll just replace the whole thing when the time comes. If it had been the original dist. I would replace it anyway but it'll have to wait for now. Thanks for the input.

zachkuby87

hahaha i was reading this thinking maf sensor the entire time and it looks like you got it my little brother was going through the same thing a few weeks ago he was replacing all types of parts couldnt figure out what it was he wouldnt let me help him he said he wanted to learn and do it on his own finally he gave in and asked me for help i started the the car and literally the very first thing i did was unplug the maf sensor the car didnt run any different i popped the hood on our parts car took maf sensor and put it in while he was in the house thing runs great and i still wont tell him what i did i tell him hes gotta learn on his own

88gta_hiflyer

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It's too bad you didn't read it during the two weeks I was asking for advice.

KNBlazer

it's hit or miss... that's why you have to start somewhere in diagnostic mode and not in buy, buy, buy, till the problem is resolved... especially with 3rd gens... a lot of problems are masked... as I think this thread has already mentioned.. you replaced parts that you would have needed sooner rather than later... ..

88gta_hiflyer

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I agree. It worked out for the best that I gave the fuel and ignition systems a good going over. I didn't replace anything that wasnt needed (other than general maintenence parts) and some of the things I was planning to do anyway, this stalling issue was just the kick in the *** I needed to actually do it. I had known that my injectors were leaking for a while so it was good to get that out of the way. My fuel pump was also getting weak and the strainer on the bottom was very brittle so I'm very glad to not have to worry about that for a while. I have a lot more confidence in the car as far a reliability goes so I'm thrilled that it all worked out and grateful for the help I recieved along the way.