Help! 89 C4 fails on start second time

[hexcarnut1]

:ugh This is my first Corvette and may be my last. !989 Conv. 52000 mi. auto. w/all the power goodies. I had to rebuild the drivers door due to some Klutz trying to pry it open with a crowbar. Busted up all the plastic. Then the headlights failed and I went through the rebuild process. Had it tuned and new ign, wires, 8.5 mm, new ign. module and all the rest of the normal service things done. Oh yes, I put in PULSEPLUGS. Now to the problem, It starts first time every time but shut it off and it will not start. Turns over fast enough but will not fire. Got spark and fuel press. The second time comes at either one minute of running or over an houe so I don't think that it is a heat problem. Got the best mech. arround here ad he is stumped. We are down to the ECM at this point but cannot prove it... ANYONE ? ? ?

 

[John Robinson]

Not ECM Yet

Before you replace the ECM do the following

1. Search this forum for information on the TPS and what it does.(If you can not find anything contact me)

2. Do a careful inspection of all the wire connectors for corrosion.

As for the ECM remember it only reacts to what it is told by an army of sensors. With that understanding suppose the ECM receives a signal from (a). It processes that information and then it does (b). Well if (b) says something is wrong with the engine the ECM may go to (c)which may turn off the fuel or electric's etc.

To many times the ECM is replaced only to find out that the problem still is there

After I bought an ECM for a problem I had and it did not fix it I started to try and understand what controlled the different systems and their function. By doing this I have been able to solve what appeared to be major problems with minor fixes of a small part of the sytem.

Finally to often out of fear I guess we just seem to jump at the most expensive parts as being bad.

More important than having a good mechanic is to have a good diagnostician.

 

[boomdriver]

:ugh This is my first Corvette and may be my last. !989 Conv. 52000 mi. auto. w/all the power goodies. I had to rebuild the drivers door due to some Klutz trying to pry it open with a crowbar. Busted up all the plastic. Then the headlights failed and I went through the rebuild process. Had it tuned and new ign, wires, 8.5 mm, new ign. module and all the rest of the normal service things done. Oh yes, I put in PULSEPLUGS. Now to the problem, It starts first time every time but shut it off and it will not start. Turns over fast enough but will not fire. Got spark and fuel press. The second time comes at either one minute of running or over an houe so I don't think that it is a heat problem. Got the best mech. arround here ad he is stumped. We are down to the ECM at this point but cannot prove it... ANYONE ? ? ?

no start when hot....?fuel pressure, filter/ an fuel delivery/TPS /MAF & relays.

Lastly........swap a couple proms in/out of this ECM to see what happens. Same stuff....get a $100 rebuilt ECM and GO

 

[hexcarnut1]

End of Problem

Well believe it or not the problem turnedout to be 3 1/2 bad Injectors. The 1/2 was intermittent. Things I found out: The NOID light HAS to be bright or the injector is suspect, when OHMINg out the injectors the reading has to be within 15.8 to 16.9 ohms, mine ranged from 2.6 to 16.9, The car ran with all the bad injectors unplugged, not well but it ran. This only took about three weeks to figure out.

 

[boomdriver]

Well believe it or not the problem turnedout to be 3 1/2 bad Injectors. The 1/2 was intermittent. Things I found out: The NOID light HAS to be bright or the injector is suspect, when OHMINg out the injectors the reading has to be within 15.8 to 16.9 ohms, mine ranged from 2.6 to 16.9, The car ran with all the bad injectors unplugged, not well but it ran. This only took about three weeks to figure out.

Well, its figered out....now you can ENJOY !

You Will !