350tbi stalls for fuel cutoff

[geauxnow]

I meant exactly 5min after a cold start. not that the engine was cold. sorry.

Is there any history or basis to the time of approx 5 minutes on these ecus?

 

[gmbellew]

Is there any history or basis to the time of approx 5 minutes on these ecus?

just what the manual says....that there is a time component to when closed loop goes into effect in addition to engine temp and O2 oscillations.

 

[geauxnow]

Best I can tell, Closed Loop for the fuel pump relay begins at 4psi, and not time. I really need to troubleshoot that circuit.

 

[gmbellew]

Closed loop is when the ECM is using feedback from the O2 sensor to adjust fuel trims. Open loop is when the ECM is only using CTS, TPS, MAP to adjust fuel trims. It's a mode of ECM operation.

If the fuel pump relay is bad, the redundant power from the oil pressure switch will go through to the fuel pump as long as the oil pressure is at least 4psi, either from the engine running or extra cranking.