cosmicvette

Hi all,

I just picked up my '90 L98 auto, completely stock.

I was driving it around for about 30 mins, then when I was sitting at a set of lights it just stopped and would not restart. I then waited a few minutes and tried again and it started and idled ok then stalled after driving off a few hundred meters.

Called a friend and they came and jump started me (in a '87 C4 not that that matters ), the car did the same thing.

I thought it may be battery related but we started it up and left it electrically connected to the other car, it would sit there and idle but when you hit the throttle it would just cough quickly and die. So I thought it was battery related but after that I started thinking otherwise.

I thought the gas may be bad because the car has been sitting for a while (about 6 months with the same 1/2 of a tank) we filled it up with premium (about took about 30 litres (thats about 7-8 gallons) to be full).

We then had the car towed back to the friends house (so it was sitting for about 45mins-1hr cooling down).

We then tried again and the car would crank every time (so I assume that means the battery wasn't the problem) and start and idle fine but still sound like it was missing when the throttle was applied.

The fuel pressure was tested (we were thinking the pump may be bad, but the fuel pressure held rock solid even at WOT).

Our friend thinks now that it may be ignition related (the ignition coil?), what do you guys think?

I am stuck a long way from home and need to sort this out asap, really appreciate your help.

Cheers,

cosmic

btw: I love the car (even with this problem)!

red_johnny

Sounds like it could be the coil. Check connections also. See if when you wiggle the wires around the distributer (not the plug wires) if anything happens differantly. Then try wiggling the plug wires. First check the connectons at the plugs and cap. Good luck

madmatt9471

Post this in the Tech/Performance section and many more will respond quickly! I'll write back on this soon!

Thanks,Matt

aminnich

The sitting for 6 months with 1/2 tank would be cause to suspect condensation, ie water, in the fuel tank. Check for codes, but water in the gas wouldn't throw a code. Adding premium gas would do nothing to dissipate any water in the tank. Dry gas or isopropyl alcohol would do it if this assumption is correct.

MikeC4

somewhat. I would suspect your ICM before the coil. The ICM is more heat sensitive than the coil. Coils are pretty rugged units. Check your cap/rotor for carbon tracking, replace if necessary. Best way to determine if your ignition is at fault is to drive it around close to home to try to get it to conk out again, then pop out a plug and check for spark. Also, look for any arching around the distributor area. Do this at night in well ventalated garage or in driveway. Back to the ICM, who knows how old it is? On your '90, is the ICM still located inside the distributor? No matter where it is, it will be mounted to a piece of metal or aluminum(heat sink), and there needs to be a good smear of heat sink compound BEWTWEEN the ICM and heat sink. Inadequate heat sink compound leads to hot spots from the ICM and they can malfunction, as this is an electronic circuit....and heat is the enemy here...

Also, see if you have any stored error codes, this is another "first thing to check for"....

Last thought...your fuel pump...another heat sensitive component. It amy have worked fine after cool down period, but spazes out after long operation. Duct tape your FP gauge to your windshield and see what happens when engine quits again...

Corvette Kid

Both with coils and electronic components, when they are failing the problem will often grow worse as engine temps (and thus the suspect component's temps) rise.

CJB

C4....Problems.......... How could that be in the same sentence.

Good Luck!!!

bogus

No codes, Alex?

cosmicvette

Hi guys,

Thanks for the replies.

I don't have access to the car right now it is at the guys house I towed it to last night and will be going over there in a few hours.

I didn't get a chance to check for codes last night, but will today.

The car had been driven previously on a couple of short trips without any sign of this problem.

I will keep you guys updated when I look at the car.

Cheers,

cosmic

jhammons01

is it cold down there this time of year? We may be thinking heat related problems becuase it is summer time here.

C4boy

Bet ya a donut it's your control module (under your distributor rotor).

JrRifleCoach

See your donut and raise a box of cheesits

cosmicvette

Hi all,

Sorry for not replying sooner I have been away from a computer.

First let me say thanks to everyone that replied with help. If any of you come down under let me know and you can come round my place for a beer.

The car is running fine now........what was it?...........................


It was the ignition module, the heatsink grease was almost all gone and the unit looked bad. The coil was also replaced as it looked pretty bad also but the cause of the problems was the module.

Other than that problem all I can say is WOW I love my '90. The ride compared to my '70 (don't get me wrong I still love my '70) is amazing.

Cheers

cosmic

rocco16

I love a story with a happy ending....

Larry
code5coupe

Redhook98

wmupaprmkr

congrats on the fix...now go out and enjopy it!

corvetteronw

Let me send you a copy of the Chris Petris C4 book from his Bloomington Gold '05 class. It has a lot of good info that you could use in the future.
Just PM me with your mailing address there in the land of Oz and I will mail it to you. Freebie for a brotha down unda!

cosmicvette

No way! Thats awesome (Pm on its way).

Thanks everyone for your help. Car is great, pics are on the way. Haven't had a chance as I've been having too much fun driving this beast!