lovmy90vette

I have a 1990 corvette and was driving it in northern Michigan last weekend. I filled up the tank with premium like I always do and drove it about 180 miles. Stopped for dinner, and within a mile the car stalled at a traffic light. I had some difficulty starting the vette. When I was able to start the car it cut out as soon as I pressed the accelerator. About 3 hours later wile waiting for the tow truck, it started up and ran like normal. Anybody got any suggestions???

antfarmer2

I would put a fuel pressure gauge on it and tape it to the windshield. If it dies and the pressure is good I would test the icm and coil. Most places do it for free but would take it to more than one. Some do not know what they are doing. If no pressure gauge I would do the free test. I would also pull the vacumm line off the FPR and smell for fuel.

lovmy90vette

antfarmer2,
Thanks for the reply. Your technical expertise is quite a bit over my head unfortunately for me. It sounds like others on this forum have had issues with the Ignition Control Module. Can you recommend where I could order this part for my 1990 coupe? Also, not sure what the free test is? and last what is the FPR? Sorry to bother you but I just don't have the car mechanics expertise.

antfarmer2

Any part store will test your icm and coil for free but since it is out hit a few many do not know what they are doing. And they will have the parts better to buy local. FPR is the fuel pressure regulater.

You can check for codes with a paper clip look on youtube and pray it is not your opti.

WVZR-1

Where's this fellow's "opti"?

OP - order no parts before doing any diagnostics. Remove nothing that the previous poster has mentioned. There's no need for "prayer" that it's not the OPTI. Do you have a CEL (Check Engine Light)? Have you been driving regularly since the failure or just parked?

There's much to check before you buy anything.

The fuel pressure check is a very good occasional check anyway. What have you done for maintenance recently?

An L98 owner that does his own maintenance will likely stop by this AM and maybe offer up a "practical" procedure for diagnostics.

I had a "Coil in Cap" HEI engine that I had similar issues with many years ago but was a TBI, I actually checked internal distributor wiring and the pole piece connector was pretty damn nasty looking (corrosion). I replaced it (pole piece) when others said "ain't no way" it's the issue and never had another issue. Replaced engine at 300K - Mine would be fine for weeks at a time, might have the issue then cool down start again and run for a few more weeks before failing. I ain't suggesting just doing it because it's a damn nuisance to install - just wait for an L98 owner to offer up a more reasonable approach than what's been mentioned.

divotdug

I had a similar issue with my '84. Granted a little different engine but the same issue. Filled it up, drove a bit, had dinner, headed home, stalled would not start. In my case it was a failing front coolant temp sensor. Only 35k miles but still 32 years old.

The challenge for the OP is that by his own admission he is not much of a mechanic.

The challenge for us that would try to help him is he hasn't provided enough information. How many miles, when was the last time the fuel filter was changed, when was the last time the fuel pump sock was changed, has it only happened the one time, did he let the tank go unusually low before filling up, etc.

This is one of those issues that you may not be able to successfully resolve until it fails again. All you can do is some logical preventative maintenance.

Purple92

OP - The very nature of intermittent problems that go away on their own makes troubleshooting quite difficult, and even more so long distance.

Fundamentally an engine needs three things to run - compression, spark, and fuel. If the car got you somewhere and didn't end the journey with some kind of catastrophic mechanical failure we can assume it still has compression. So if you encounter a no-start condition, you need to check for spark and fuel.

To check for spark, pull a spark plug wire off - hold near (say 1/8" away from) a well grounded piece of metal (say the alternator case), and have someone crank the engine over - if you see a spark - you're in good shape there. If no spark - you need to figure out why the ignition system is not working - it could be a dozen different parts, but on a 1990 - you have what GM calls the HEI distributor, and I'd probably pull the coil and change that first - the other fairly likely culprit is the "module" that sits in the distributor.

To check for fuel - your a bit luckier than some - you have TBI (throttle Body Injection), so pull off the air cleaner and see if it appears that some fuel is being squirted in as the engine is cranked over. If no fuel - you need to see if you have fuel pressure. Do you hear the fuel pump run for a second or two when you turn the ignition on ??? If not - the test procedure involves temporarily bypassing the normal wiring, and putting power directly to the fuel pump (usually done by pulling the fuel pump relay and sending power to the pump) and seeing if that makes the pump run. If the pump is running, buy or borrow a fuel pressure gauge, hook it up to the fuel rail and crank the engine (or power the pump directly). If you have fuel pressure - and no fuel is being sprayed - you need to do some EFI diagnostic work - typically one of the sensors has failed and the computer doesn't think that the engine is trying to run.

Speaking in the most general terms - people have more problems with ignition systems than fuel systems.

GOOD LUCK !!

WVZR-1

OP doesn't have a TBI

The suggestion of coil replacement and module replacement involves time and $$$ that could very likely be a wasted effort.

Very much of the "what's involved" NEXT I'd think needs to be determined by the # of times this condition presents itself. The OP should do the fuel pressure check(a maintenance function), check the FPR likely but I don't believe he needs to start just throwing parts at it OR removing for checks.

Red1990VT

The suggestion about the coolant temperature sensor was a good one. I had all sorts of odd problems that turned out to relate to the car always thinking it was cold and needed to enrich the fuel mixture. Which in turn created all sorts of problems. Once I replaced the CTS, the car ran great.

Also, checking the fuel pressure is a great idea. There is a schrader valve on the passenger side of the fuel rail, you may need to remove the MAP sensor to access it - at least I did. The pressure should be around 43 with the car running and it should hold once the car is shut off. It the pressure comes up to the low forties, but drops immediately upon shutting the car off, it could be a bad injector(s), fuel regulator, or a bad fuel pump check valve. I knew I had at least one bad injector, and so replaced all 8 injectors (in my case with OEM Delphi injectors, same as the ones from the factory), the frame mounted fuel filter (what fun that was) as well as a new fuel pump.

Of course, the car still ran poorly until I replaced the coolant temperature sensor (and used the opportunity to flush and fill and put in a new 195 degree thermostat). Then the car was back to being a total rocket, great drivability across the full range.

One last thought, I know people suggest putting in lower temperature thermostats, but since the fuel injection system was calibrated with a 195 degree thermostat, I'd suggest sticking with that.

Hope all this helps, interested to know how it turns out for you. Sounds like you enjoy your 1990 as much as I do mine. Great year for Corvettes.

lovmy90vette

So here is some of the details....the 1990 vette has been running great until it died 55 miles from home ($220 tow charge). The engine would crank and occasionally start but as soon as I pressed the accelerator, the engine died. So my wife and I called a tow truck and waited for 3 hours. Right before the tow truck showed up the car started back up like there was nothing wrong. We decided to tow the car rather than be stranded again in the middle of northern Michigan waiting for another tow truck in the dark. I had no check enging light and the car is in storage now. I added fuel stabilizer yesterday and ran the engine for 7-10 minutes without any issues.

The vette has about 32K miles, I filled up the tank with premium and we drove about 180 miles. I set the trip meter in the car because my fuel gauge shows full all the time (need to fix that sometime). So I know I had fuel and since it started up before the tow truck arrived I assumed I had sufficient spark and fuel.

My guess from all of your input is that it's time to replace the Ingition Control Module which I understand is in the distributor Cap. Should I also test the Coil, assuming I have one??

antfarmer2

First just test if it cranks and no start shoot some fluid in it then if it fires it is fuel related. If not most likely spark. Then I would test the icm and coil. Then replace if needed. Sorry about my butt sniffing troll but he is right yours does not have a opti. Sorry I do get some threads mixed up. And checking your temp sensor and connections.

Joe C

quick question - have you done, or had done, any service work lately?
w/some - don't just start throwing parts at the issue - perform some basic diagnostics first. ID a direction, then move on.

good luck - keep us posted -

divotdug

Can't agree enough. Don't just start tossing parts at the issue.

My first question is, has it only happened this one time? From your description so far, it sounds like that is the case.

Until it happens again you really cannot perform basic diagnostics to determine if it is a fuel or electrical issue.

If I were to do anything while it is winter storage, I would go ahead and replace the fuel pump/sock/pickup assembly along with the fuel filter. Not that expensive and gives you a working fuel gauge.

Joe C

good point on the fuel filter. if original, that puppy is 26 years old. most guys overlook the importance of a $10 filter as a maintenance item. it's not a waste of time or money. I just pulled one from my 90 - it looked relatively new, most likely it was replace sometime, just before I bought my car. changed it because it was stamped "made in china" and no brand identification. replaced with a good old, made in the USA, GF652, ac delco.

WVZR-1

OP - What have you done since you had this experience end of August? Do you maybe have the '90 FSM?

https://www.corvetteforum.com/forums...post1592961575

You've apparently NOT fixed the sender issue - you mention the car has 32K. You've had how long and done what for maintenance? You mention "trust" in your 8/31 post so I'd suggest maybe a conversation with him. Ask about "coil in cap" HEI - If he doesn't know or understand diagnostics - what to do?

You can GOOGLE" HEI "coil in cap" and do many reads regarding tests, repair and diagnostics.

Earlier in the thread I mentioned an L98 owner would stop by and offer up some help.

JoeC - I thought would stop by. Others mention - until it fails again it's certainly a tough go. Yes it is.

How could he have possibly been "confused" - "mixed up threads" - I thought the first few words in your post "hinted" the concern. He was as usual a "first responder"

He still insists on carrying the ICM and coil to the parts store. If you're not familiar with HEI "coil in cap" distributor you can easily do much damage trying to get the "hands on" - he's still thinking LT engine with easy access to coil etc. Is he still confused? I've no idea -

In post #4 he mentions the parts store NOT KNOWING WHAT THEY'RE DOING - he's arrived at this how?

antfarmer2

I am trying to help here sorry if it is not making you happy. stay with your illegal selling of illegal downloads and STOP TROLLING ME YOU PIECE OF ______.

I do see you give some good info and have helped many but you are a annoying little.

VikingTrad3r

lovemy, you are in good hands here. im subbed to see what the solution is and i'll chime in if i think of anything not covered yet.

basically, check fuel delivery (simple $20 fuel pressure tester is all that is required), check ignition (gets a bit more complicated but as said up post, simply removing the dizzy components and taking them in for test would work. note that when testing the IGM, take yourself a hair dryer and extension cord and hit it with the heat as you are testing it. like plug it into the wall and blow hot air on it so it simulates heating up. these electrical connections can crap out and begin failing under heated conditions only). edit: you don't want to use a heat gun here....and you don't want to melt it...you are just trying to simulate the heat while running.

cv67

x2 on checking fuel pressure that one is very simple you can do it
same symptoms it was the fuel pump. Yours is old, very easy to change

aklim

Not sure how good the Delco ones are these days with all the stuff going to BFE for cheap manufacturing but that or ACCEL or MSD is reasonable From what I see. ICM testing is hit or miss depending on the competence of the tester at Autozone or places like that. They have told me that my starter and alternator was good before. Only problem was the rebuild shop took it apart and we saw all kinds of crap in it. Your call. You can buy another one just to have a spare if it is good.

aklim

I'm not a big fan of codes simply because this ECM is rather primitive and doesn't always throw a code but it is a decent place to start. Maybe better if he owns a scanner.

As to his opti, I got $50 says that if he is stock, his opti is missing.