Crank No-Start/Idle 91 ZR-1

[BaggyToaster]

Hello everyone, I have been a long time reader of these forums and the information has been quite helpful. I have a 91 ZR-1 that has been plaguing my existence. I first diagnosed a crank no start as a bad ECM due to lack of injector pulse and continuity to ground through ECM when cranking. Had the ECM rebuilt and the thing started right up and ran like a top for 3 days. On the 4th day I shut the vehicle off and when I went to restart it, it died instantly. I have initial injector pulse for cold start key on for all injectors. It cranks, fires off of initial pulse fuel, then dies within 2 seconds. I have good spark at all plugs, good cam and crank sensors with good continuity to ignition control module. The only thing i am losing is injector pulse once cranking. I have no ECM or CCM codes. Could the ECM have gone belly up again? I have hit a wall and would appreciate any feed back or additional diagnostic routes that I have not explored. I have a FSM for the vehicle as well.

[Marc Haibeck]

Try these two suggestions.

Is there a VATS lockout? With the door open and the ignition key off the Security light should be blinking. Close the door and try to start the engine. Is the Security light off when you have the ignition key on?

Observe the fuel pressure when the engine is cranking and not firing. The fuel pressure must be over 30 psi for the engine to fire. What is the fuel pressure while cranking?

Marc

[BaggyToaster]

Security light flashes normally. Key in and ignition on, security light goes out. Starter cranks normally but engine will not continue to run. Fuel pressure is good and does not fluctuate while cranking.