Fabinatl

Car cranks but will not start - gets SYS Erra flashing. Pulled the codes and keep getting a C-41 ECM erra. Manual says it could be the computer, ignition module or fuel pump. I think it's the computer gone bad. I disconnected the battery a couple of times and it still gives the erra and will not start - just cranks. Sounds like the fuel pump runs and everything looks normal. Going to get the manual out this weekend and start the trouble shooting steps. I was hoping to get some feed back before I start.
What do you guys think? Any suggestions of what to check first?
I really don't want to just throw parts at it.

HELP!
Thanks,

Andy Booker
404-499-5661w
770-973-5535h
n4wwt@bellsouth.net

onedef92

I hate to hazard an uninformed guess without the service manual and some diagnostic procedures, but from what you've described, I'd lean toward the computer, then the coil and/or ignition module...

jfb

Engines need spark (and at the right time), fuel, air (and in the correct ratio) in order to start and run and that is what you look for when your engine won't start.
Is there some reason why you want to keep the year vette from us? It sure would help a lot as all C4's were not built alike.
Use a timing light to check for spark and spark timing. Use a fuel pressure gauge on the shraeder valve on the end of the fuel rail to see if you have the correct fuel pressure. Unplug an injector and place a noid light (available from parts stores), or a low power 12v lamp like a 194 side marker lamp across the injector plug and crank the engine to see if the lamp flashes which shows that the ECM is pulsing the injectors. Now somewhere here you are going to find the reason why your engine won't start! Follow the procedure in your service manual for the error code you found!

Fabinatl

(92 auto LT1)
Ok, I followed the steps in the manual for the code 41.
It says "Short to voltage in EST circuit". This is where it ends.
What does this mean? Where do I go from here?
Any help would be appreciated!
Thanks,
Andy

jfb

Did you find that the EST circuit was shorted to ground measured with your ohmeter when you disconnected the 4 pin connector on the distributor? If so, then trace the wire on the ECM connector (pin D4 and white on my 87) all the way to the 4 pin socket on the wiring harness that plugs into the distributor and see if that wire is shorted to ground somewhere along its length. If your ohmeter measures very high resistance, then circuit 424 (bypass wire) is open or it doesn't make connection from the ECM to the distributor 4 pin connector OR you have a faulty spark control module. My money is on a faulty spark control module which is inside the distributor and you can remove it and have it tested at a parts store. Call around to see if any parts stores near you can test the module.

Ricks94vette

My 94 did the same thing and it turned out to be the ignition module(upper front side of engine. You will have to seperate it from the cooling fins though). Not a big deal. Good luck!

Fabinatl

Well....I replaced the ignition control module and it did NOT make a difference! Still get the same c41 code and will not start....just cranks.
I also removed the after market alarm system just to be sure. It still will not start up. I guess the ECM/computer is next. Battery is charged up and it will crank forever...just will not start. Something is inhibiting it from starting. Anybody have any other ideas? Should I go ahead and spend the money for another computer? Any body got one to sell?
Andy
92 A4 Lt1

CFI-EFI

Is it getting spark? Fuel?

RACE ON!!!

jfb

Use a timing light to determine if you have spark and if it occurs at the right time by having someone crank the engine while you check for timing. Put a fuel pressure gauge on the shraeder valve on the end of the fuel rail to see if you have correct fuel pressure and if it stays up when you turn the key off. Remove an injector plug and put a noid light (available at parts stores), or a low power 12v lamp like a 194 side marker lamp across the injector socket and crank the engine. The lamp should flash showing that the ECM is pulsing the injectors. Engines need spark, fuel , and air to start and run. You are missing one or more of these, find out which!

tnt-sportfishing

Do you have a fax machine I have the actual service manual for the 92 vette i have a 92 vert. I looked up the code I have two full pages on the trouble shooting and fix. It would be alot to type, it also has diagrams. Jeff

Fabinatl

Well...I have the sevice manual and did follow the diagnostic procedures.
It pointed to the coil control module and I replaced it and it still only cranks. I also charged my battery to the max.
It's getting fuel, but the computer is turning things off for some reason.
I guess it's time to buy another computer module.
Anybody have a 92 A4 LT1 type for sale?

tnt-sportfishing

Ebay

Fabinatl

Just replaced the computer and the car started on the 1st crank!
Yea!

onedef92

You had a bad brain. Yippee!