Dean_GTA

My 1988 TPI stalls out after a hour of driving, or a hour of idling! No matter what, in exactly a hour the car will stall! (like on a timer) After the car stalls out, I have to wait for it to cool down, (about 1/2 hour - 1 hour) and then it will be ok to drive until it stalls again. If I don't let it cool down, it will start, and run for about 10 - 30 seconds, and then stall!
Anyone have any ideas???

SpitotRs305

have you tested the ignition module?

cityspud117

i have been having the same problem as you are. I changed my ignition module and still no change. I think it might be fuel filter or fuel pump related. but start with the module could be a different outcome for you. Let us know.

Sonymaster20

iTrader: (3)

I'm having the Same problem except I'm able to start my car after it stalls out. Any one have any help? I also thought it might have been the fuel pump or fuel filer that was clogged but have yet to replace it.

Dean_GTA

Thanks for the responses guys!
Where is the ignition module located? I have a new MSD distributor, and the fuel pump and fuel filter are new! I also changed the fuel pump relay too! No engine codes.

cityspud117

take your distributor cap off, its a little black peice underneath. youll see two small screws holding it on i forget the size but there pretty small. should take 15 min to change it. here is a link to what the module looks like at summitracing.com http://store.summitracing.com/egnsea...=KeywordSearch

i suggest going to auto zone and get it. there much cheaper i think i paid 39 bucks for mine. good luck and keep us posted.


i gave up on mine ive done everythin i could think of so its at the chevy shop now. Ill let you know tonight when i hear back from them whats causing the stall.

Sonymaster20

iTrader: (3)

Thanks city spud. lmk What happens also

cityspud117

well i have bad news they told me 7 cylinders are running around 400 degrees and 1 cylinder running at 200 degrees. there looking into it some more so if anyone has input please let me know. Could it be a faulty valve?

Dean_GTA

I think I might need a ignition module. My MSD distributor is a year old and has only 2000 miles on it, if that! I took off the ignition module (Warning MSD has their ignition modules soldered at the contections.) I took it off so tomorrow I will put my old one on. I have to make a new connector and connect the wires. I'll see if the old one makes the car stall. The one that I took off the MSD distributor smelled a bit burnt! I'll let you guys know.

I'm getting fed up with this car! There's always something wrong with it, and everything has been replaced!

Dean_GTA

Put in the old ignition module, and there was no change! Just like clock work. The car stalls out after a hour. Could it be the computer?

cityspud117

i just had the same problem as you and today the the chevy dealership after 2 days of trying to figure out the problem said it was my ecm chip and put a new one in. Now she runs better than ever. might be best you just give in and bring it to a shop.

Dean_GTA

How long was your car running before it would stall? Is it the chip that plugs into the ecm, or the whole ecm? I wish I could take to someone. I have taken it to a couple places that were highly recommended by others. They had no clue what they where doing, and they would always mess something up!

cityspud117

the whole ecm chip was replaced. My car would idle rough without shutting off but soon as i would turn it off it wouldnt turn back on for at least 20 min., or if i was driving and my foot wasnt on the gas it would shut off....i drove around and had to pop it in neutral and hold the gas down or id stall. take it to a chevy dealership. i had another thread going about this issue i have a cold cylinder and the guy said it has nothing to do with the ecm so i need to see what is up with that. So far it hasnt been stalling im going to drive 2morrow for a while so we'll see what happens. ill keep it posted.

Sonymaster20

iTrader: (3)

Thanks, This seems exactly my problem except it doesn't happen as frequent as you have had it.

Also Where is the Ecm chip located exactly and how much was it.
Also where did they get the chip from?

It's sounding really familiar, My Iroc-z would be sitting for a while and when I went to start it up it began to rough idle also. around 500-low 600 and sounded like it wanted to die.

evilstuie

haven't had any experience with these particular ecms but have seen 3 different cars have the same thing happen due to swollen capacitors in the ecu. they swell with heat and then eventually pop and the car won't even start then.
If you can maybe just take out the ECU and have a look around and see if it does have swollen capacitors anywhere with the tops hemeraging.
If you catch it before it dies you can sometimes just replace the capacitors with a higher quality one or a different spec that will deal better, but you'd have to look up capacitor replacements on the net and find the calculation/ method for increasing capacitor size(or whatever they're measured in, been a while and lots of alcohol)

BlueIroc-Z

iTrader: (6)

"ECM chip" is, for later years, located in the MemCal, which is located under the small rectangular access panel on the ECM itself. The ECM is located behind the passenger side dash, you can get it out by removing the under dash panel, and undoing the ECM mounting screws.

Now, I would assume that when you take it to a dealer to 'get a new chip' they really just give you a whole new MemCal, as the chip is soldered to the MemCal. As for where they got the chip from, I would guess they still had some old stock left over and pulled one off the shelf or from a warehouse... Also, off the top of my head I seem to remember when I was looking for a MemCal for my '89 at GM Parts Direct, they were like $125-$150 ish... Might even be more from the dealer, but I don't know for sure. Never hurts to check.

If you can reliably isolate the problem to be in the 'chip' itself, you could always get one from TPIparts. They give you just a new chip not a new MemCal, their chip comes with a little adapter thingy (as shown in the pic) that installs between your old MemCal and the new chip, allowing you to retain your original MemCal, but run off the new chip.

(Little info on what a MemCal is, in case you were wondering: It's basically just a carrier that plugs into the ECM, it holds the PROM chip (this holds the programming that controls the engine during normal operation), and two other chips (resistor networks), which control the engine during startup and limp home modes. Here's my source for that info.)

Hope that helps, and good luck!

Dean_GTA

Anyone have any updates on their cars? I will pull out the ecm tomorrow, and see If I notice anything funny on the main board. I know a rebuilt ecm goes for about $90. As for the ecm prom, I don't know who has one. I called one parts place, they said they could get them??? The chips are worth about $1, but to find someone who can burn them, to factory spec is another story.

Sonymaster20

iTrader: (3)

Thanks Guys I'm looking into it

BlueIroc-Z

iTrader: (6)

Yeah, I know what you mean... I too need a factory PROM (my ECM has a 350 chip and I'm running a stock 305). Like I said, TPI Parts can get you one to factory spec, but it costs $80-ish... I think mostly what you're paying for there is the adapter thing...

If I could find someone who would burn me a chip to factory specs for like $10-$15 I would jump on it. I didn't want to make a post like that though, for fear of it being considered "PROM Begging"...

cityspud117

well the ecm chip was a failure the car is doing the same thing again. The chevy tech said he cant figure it out. The guy working on the car has been with chevy for 30 years and has never seen a car do this. He says its something with the fuel and the way its being delivered. When it shuts off though he said ether will start it right back up. I give up i have no idea what to do. it runs great cold and once its warmed up its really rough and wont turn on when its shut off unless it sits for 10-20 minutes. this is my only car so it sucks big time right now. Does anyone have anything?????

Dean_GTA

That's too bad! I know how you feel! I'm giving up on the car. I've changed almost everything! Should of bought a 5.0L!!!
I took the ecm out of the car today, took it apart, and I was looking over it with my buddy. We couldn't SEE anything wrong with it, or smell anything funny. But you have to know it is electronic, so could be internal! I called my local GM dealership (one of the biggest Vette dealerships) and talk to a jr. tech. He told me to come in tomorrow and talk to one of the senior techs, and bring the computer to test it??? I don't think they could test the ecm, unless it's in the car. I'll go in, and tell them my proplem and take it from there!

OldYellr325

Call it a hunch...

Fuel pressure regulator...


http://store.summitracing.com/partde...5&autoview=sku

http://store.summitracing.com/partde...5&autoview=sku

Injection method makes a difference as to which one. But sometimes with a small tear in the diaphram they can be somewhat problematic when the engine heats up.

Dean_GTA

Funny you would mention that! I started to have this problem after my fuel pressure was adjusted way too high. In fact... the exact same day! I have an adjustable one. I don't know if that would do anything to the regulator?

OldYellr325

Too much pressure on an injector can sometimes cause them to "blow open". But mainly it just floods the engine out because the injectors are getting way more fuel and probably cant close fully with the additional pressure. Hense the wait to restart it. The additional fuel has time the evaporate. Why it wouldn't affect it when its cold... Not sure but it certainly sounds like it is flooding.

The particular regulator in question would not be a regulator to cap the overall pressure but rather the "fuel injector" regulator. This opens up to increase pressure on the injectors at low vacuum. A torn diaphragm would be percieved as high load all the time.

If the overall pressure was substantially increased and the injector regulator is trying to hold it back that can rupture easily.

Dean_GTA

My pressure gauge was broken, so when I adjusted the fuel pressure that day I didn't get an accurate reading. The pressure was set way too high, a bit over 60 psi. The car stalled out from that point. That day was about 1 1/2 hours of driving. I check the fuel pressure the next day, and set to 43 psi. Since then the car stalls out after a hour of running. One mechanic checked the fuel injectors after that and they are all operating fine. Right now my fuel pressure is at 43 psi.

OldYellr325

Is that being measured before or after the injector regulator though?

Is it an inline regulator before it reaches the fuel rail or has the orginal fuel rail regulator been replaced with this one?

If this is an aftermarket for the fuel rail itself and it has been adjusted back down then it may not be fuel related.

If it is an inline for an aftermarket fuel pump then this particular reg may still be suspect.

Usually they should handle 60psi though. Unless it was already on its way out.

Dean_GTA

It the Accel adjustable fuel pressure regulator. The one that's in your link. The fuel pump is new, a bit over a year old. In tank 255lph. The fuel pressure is taken at the fuel rail, 43psi with the vacuum line off the regulator.

OldYellr325

K it rules that out then.

I still suspect it's fuel related. Or a vacuum leak (MAYBE, and thats a big maybe)

Sonymaster20

iTrader: (3)

Well in this thread this guy was having the same problems. He fixed it by replacing the ignition control module.

https://www.thirdgen.org/forums/tpi/...-stalling.html

I know its been said but did the module you replaced city, work?

I've also have had the hunch of it being a fuel system problem also. From the very beginning It always seemed the car would just cut out from it not receiving fuel. Do ya'll have new fuel filters?

Or maybe the fuel pump maybe shorting continuously in and out?

Dean_GTA

Could advancing the timing too much, cause this problem?

OldYellr325

Nope but pulling too far back could.

Too far advanced to even start would sound like the engine was barely turning. Would sound like it falls dead, then rotate, then splat, then rotate.

five7kid

iTrader: (14)

Make sure the evap system is working correctly. If it is sucking the pressure off of the gas tank, fuel can't be pushed to the engine. Quick way to check is to remove the gas cap after it stalls and see if it starts then.

Dean_GTA

Yes, I checked today. It's a lot cooler outside. Right on schedule, the car stalled out at the 1 hour point. I took off the gas cap and there was no pressure. (on hot days pressure build up) Had it off for a few seconds and put it back on. Started car and kept stalling! No change! Dealership wants $105 an hour, to troubleshoot. So that's out of the question!

Vortex91

Are you sure the fuel pump is OK. It sounds like something operates for 1 hr no matter what the operating conditions are (speed, RPM, temp) and it still fails at the 1 hr mark. The only thing I can think of operating within the same parameters for 1 hr is the fuel pump. It's almost like you run the car for 1 hr, the fuel pump overheats or there is some sort of electrical connection that overheats and you end up with no fuel (or dead electrical connection).

I'm not sure if you are still looking at the EMC but I remember coming across a site where they had the EMCs for $40 (not just the chip).

This might not be related but about 5 years ago, my car would almost stall, took it to the dealer and turned out the cat was plugged, they also replaced the fuel pump but they made lift the cat and it was HEAVY. Who knows, maybe your cat is plugged but I don't think it would cause your car to stall exactly after 1 hr.

It can be very frustrating but when everything is fixed you will be back to having fun.

Good luck with it and when you fix it don't forget to post the solution.

D.

80schild

iTrader: (5)

Can't a bad coil cause it to shut off after warm up?

BlueIroc-Z

iTrader: (6)

EMC = ECM, right?

So they were selling the complete ECM + MemCal (chip) for only $40, or was it just the ECM? If you remember the site, I would like to check it out.

Thanks.

Dean_GTA

Coil I put on is pretty new. MSD blaster, but you never know!
I ran the car yesterday. The car also at cold start up, starts right up and then stalls. Starts right up and then runs fine for a hour. After the hour, I got my buddy to start the car. We had to start it a few time, for it not to start at all. 3-4 times. (start stall, start stall... each time the car ran for less, until it would barely catch.) Removed a spark plug wire, and found that there was no spark getting to the plug. Also the car was running a lot richer. Smelled too rich the whole time running.
I think since I tried the ignition module, the coil and distributor is new, plugs and wire new too, I might chance it on an ECM.
I'll let you guys know.

boldguy

do you guys have electric fans??


Something grounds in the ecm when its time for the fans to come on... I'm still pretty new on this but somerone can elaborate.

Also, coils commonly fail at operating temperature... If they are the stock ones on all oyur guys' cars, that is most likely the prob.

After it dies it will crank right?? just no fire?

Dean_GTA

After the car stalls, it cranks, starts and runs for about 5 seconds. After 3-4 times of doing that, it will just crank. You would have to wait about a minute. Then after that, it will only run for about ten seconds.
The coil on my car is fairly new, and it's a MSD Blaster coil.

boldguy

"New doesn't necessarily mean good", someone on these boards told me that.

I am not too impessed with MSD's stuff. Sure its made in the USA, but again that doesnt mean that it is good...
Do you know how to test a coil? Test it when its cold, then test it right after it stalled that oughta tell you. If theres no spark getting to the plug that should tell you its the coil. Test her out.

Dean_GTA

Would I take off the wire from the center of the distributor car, and see if it sparks? I took a wire off a plug and there was no spark, as the car was hot, and trying to start.
What's a good brand of coil?

Vortex91

Hey Blueroc-Z, yes EMC=ECM.

I don't remeber the site, I though I had it in my favorites at work but I can't find it. All I remember is that they had I list of ECM and prices, no fancy drop down or anyting like that.

I'll look at home as well.
I was sure I had it bookmarked.

cityspud117

yeah mine just cranks and cranks and sounds like it wants to fire but it wont until it cools back down. Usually 20 minutes. But when im driving it its the roughest drive it skips and hesitates like a bastard. Any ideas.

Dean_GTA

I will play with the car tomorrow. It sucks because I have to wait an hour for it to stall, and I have to do it during the day because the car has a loud Flowmaster exhaust. I will check for spark again, and will buy a good fuel pressure gauge. I want to see if the fuel pressure drops, when it's about to stall.

Dean_GTA

Ran the car today. It ran for 1 1/2 hours before it stalled. It always stalls at the 1 hour mark, just like it's on a timer. But today it ran for a 1/2 hour more. When the car tries to start, there is no spark going to the spark plugs. Also when the car is running, it is running too rich! Where does the distributor get its power from? Does the computer tell it to spark?

Vortex91

This sounds like the coil is not good. How did you test for spark? Did you check just one wire or more?

If there is no spark then you will have unburned gas hence the rich condition.

Dean_GTA

The car runs too rich the whole time it is running? And fuel pressure is set to factory 43psi.

Vortex91

Could this be an issue with the VAT?
I think when VAT kicks in you can crank but no spark. Would VAT let you run the car for 5 secs and then kill the ignition?

five7kid

iTrader: (14)

Classic coil and ignition module symptoms. One going bad often takes out the other. Since you have a Blaster coil, not as likely to be it. Have the ignition module tested (might as well figure on changing it).

The distributor provides the triggering for the ignition. The ECM only determines the amount of ignition advance. Disconnect the EST wire (like you do when setting the timing), it'll go into default mode and only the distributor/ignition module will be doing the work.

cityspud117

guess ill figure on changin my coil and see if that works. I did the ignition module had it tested and it was no good.