Greetings,
i have a 1992 chevy suburban 7.4 that is stalling out while at base timing. I have shot the parts cannon at her and I'm not sure where to go. She does had 330 on the dash but the truck can barely idle for over 2 minutes. Starts crisp and runs as it should for the first 60 seconds.
When I turn the truck on the motor runs decent for a minute with the EST connector disconnected but quickly tries when engine goes to lower RPM.
No codes but codes on odb1 besides code 42.
Base timing set to 0.
Has new Distributor
New IAC
New TPS
New Ignition Wires
New knock sensor
New timing chain
new ignition coil
new map
new egr
new o2
new engine coolant temp sensor

1) not sure how to test the computer or PROM
2) i know these trucks are riddled with grounding issues. Would this kill the engine without the spark timing by-pass connected
3) someone tried to steal it so i needed to hotwire it myself

 

Welcome to the forum. Sounds like the problem is associated with when it goes from open-loop to closed-loop as the engine warms up.

 

it does seem like that. I unplugged the o2 sensor and tried grounding it out when the problem arose by there was no success.
next up us checking the wire or seeing if i can ground the ecm closer to eliminate the wire. How else can i check open and closed loop?

 

Sorry but I can't help you with that question. Maybe someone else on the forum can chime in with some help.

 

I unplugged the battery today and tried to check for a short but did not have the test light illuminate. Vehicle starts strong, clean and seeminly healthy but slowly keeps idling lower and lower till its goes below 700 and has issues.