I have to replace my ECM on a 1989 vette

Question 1: AC Delco for $114 OR Cardone for $72.00 (both are remans and core charges above $100)

Question 2: Reason for purchasing ECM is due to code 54 (extended crank time) - Can this be resolved without replacing entire ECM by some kind of repair shop

Question 3: Will the car run correctly with the new ECM or is there some kind of 'break in' period to determine my driving habits

Thanks for any help

 

Isn't code 54 for the fuel pump relay??? A bad fp relay would CAUSE extended crank time, while the engine builds sufficient oil pressure to close the oil pressure switch. Where did you get the ECM problem info? Have you followed all the trouble shooting steps on your factory manual?

RACE ON!!!

 

i have an 89 ecm if you need one..

 

85 Auto,

You have a PM

 

Having similar condition, esp when cold...
Have you considered CFI-EFI's explanation before you get another ecm?
Makes sense...

 

Hee Haw,

Mine only happens when cold

Give me more info on CFI-EFI's explanation

Car only starts because of the oil pressure reaches a certain PSI (The oil pressure is the starting 'fail-over')

I followed the Corvette Service Manual flowchart and it leads me to the ECM

I replaced the fuel pump and relay (didn't resolve my extended crank issue)

Chris

 

Hard start, when cold, can be an injector problem. My '89 was like that from the Factory (I even watched the salesman crank it for what seemed like an eternity before he was able to get it started for a test drive). It remained that way for 10 years and I finally replaced the injectors with cheapo Accels. Now, I barely turn the key and it fires it right up. You might try turning the key on a couple of times, but not starting it when cold. That will ensure that the rail is primed. Otherwise, testing the injectors may be problematic. I bought a tool to momentarily energize each injector so that I could measure the pressure drop, and all were within specs (though the acceptable range is very small and difficult to measure with most pressure gages). Resistance was even hot and cold. I removed the rail and turned on the key watching for fuel to drip from one or more of the injectors, but didn't see any. I then left it overnight with a towel underneath them, but never found any evidence of a leaking injector. Replacing them fixed the problem, but I have no idea as to what was wrong with them -in fact, I spent 10 years thinking the hard cold start was normal.

 

SunCr,

The fuel rail is never primed because the impulse from the ECM is never sent - Go out to your vette, turn off the radio, turn the key to the 'on' position - You should hear the fuel pump run for two seconds - I have never heard that sweet sound

I thought that leaking injectors was a hot hard start issue because they lose the pressure

I used the Corvette Service Manual flowchart

Hit me back

Thanks for all of the replies and suggestions

 

CR Sun / Hee Haw,

There was a huge thread about extended cranking for ONLY cars built in 1989 - Skip someone started the thread and it had about 50 or so responses - The reason I mentioned this is because I saw that both of your vettes were 1989's

 

For me, cold start was always and extended crank; hot was fine. Assuming there isn't an open circuit between the Relay and the ECM, then the ECM is the problem. It's about a 15 minute install. Make sure the PROM is seated. Starting and driving it for a mile or so should be enough for it to relearn the engine's operating parameters.

 

Well even though the 89's may have injector issues, mine still does this even after installing new fms 24's. So I don't think mine is an injector problem...now thinking maybe ecm as suggested above.

csc67 - have you resolved this yet?

 

If you haven't done so, make sure there is 40 to 42 psi at the fuel rail within 2 seconds with the key on. If 0, then the Relay may be bad and to check it out, apply 12 volts to Terminal G at the diagnostic link. If the pump runs, verify 12 volts on the orange or battery feed, 12 volts for 2 seconds on the ECM driver, dk green; 12 volts for 2 seconds on the output to the pump, red; and the ground, black/white.

If pressure is less than 42, but above 0, you can pinch off the fuel return line (there are flexible hoses near the tensioner) and observe what happens when you turn on the key. If the pressure rises, it's the regulator. If it doesn't, it's the pump or the filter is restricted.

Once started, you can check out the oil pressure switch by disconnecting the Relay - it should continue to run.

 

I might as well add my $.02 worth!

I have an '89 that started great. But then I had a bad injector that shorted out my ECM. I replaced the ECM and it started OK, but ran badly. I put in a set of Bosch injectors and now she starts poorly and runs badly, plus the service light comes on! Mileage dropped about 5 mph. Something is not right!

So, I ordered a set of reman'd Multecs and will put them in later this week. We'll see what happens!

 

You might want to find out what the service light or code is first. Don't know how a bad injector would fry the ECM. It supplies a ground for the injectors and since it's a quad driver, it going to shutdown the circuit when there's a problem, but otherwise save the ECM. Sounds like you might have an open or short to ground on the ECM side of the harness and if wasn't fixed before you replaced the injectors, it isn't going to run very well. Check the injector connectors and make sure none of the terminals are touching - sometimes you have take them apart to find it. Check resistance of the ground or driver circuit from each terminal back to the ECM connection.

 

SunCr,
Do you know if aftermarket rebuilt ECM's are OK to use. I've heard that any rebuilt part can be faulty. What do you think?? The ECM I just recently purchased was from NAPA, but a friend said most rebuild ECM's are done by Cardone. Is Cardone a decent company??? jzvette

 

Will an ECM from any other year and or model work in an 89? I am having injector/ECM problems too on a brand new L98 383. What is up with 89s and injector problems!!!!

 

I haven't looked through the wiring diagram to verify this, but this is what I've heard: if an injector coil's resistance gets too low, too much current flows when the ECM pulses the fuel injector and the circuit burns out.

Ben

 

I've always used GM ECM's replacing 3 under warranty (between '89 and '91). Two of the failures were related to the a/c and IAC control. A third, as I remember it, was a complete failure with it spitting out every conceivable code. No problems since. As I understand it, GM updated or improved the design after the initial production run. You may all ready have a reman in your '89; label will identify it as such and many of the sources I've read say there were a host of failures.

The skinny on Multecs is that fuel is used to cool the coils and that eventually destroys them. I had one tested that I suspected of being bad. Peering into the inlet I noted it had a square washer or sealing ring in the opening (rather than a round one). I was told that it was production variance and the injector tested fine. Still replaced the whole set - even though they only had 55k on them. One of the better 200 bucks I've invested in this thing.

All I know is that GM has preached for years that a Quad driver is going to shut down if there is an electrical problem with a driven device, issuing several bulletins chastising dealers for replacing perfectly good ECMS (and I think at one point telling them they wouldn't be reimbursed if a warranty ECM tested out ok). Who knows, but with it running like crap after replacing the injectors, I'd investigate the wiring first. All the ECM is providing is a ground. Finding out what the diagnostic code is might give you a clue. So would a good scan - I'd pay attention to BLM #'s.

 

Westifer23: Where did you find the remanufactured Multed injectors for the 89? I was told that these injectors were not "repairable"! I have installed Bosch injectors (from a 88 as Bosch were stock on this year) due to shorted Multecs. Any info you could give me on this would be appreciated!
SAM

 

As far as I know, Multecs can be reconditioned or cleaned so that you have a matched set, but if the coils are shorted, they're trash. Did you try Street & Performance - www.hotrodlane.cc - Looking at their catalog, they ask that you call for injector service or parts.