91 ZR-1 Cutting Out Under Load

[tomtom72]

Greg,
Let me run this by you about the O2 sensor #'s. The sensors should respond to changes in the A/F ratio as adjusted by the ECM, therefore there will be no set number in mV's that appears. Near as I can figure if the mV's are not constantly varying then the sensors are getting lazy and or going out to lunch. They react or read what has already been done by the ECM to the A/F ratio via the injector pulse width changes. In short I think they either work or don't with a lazy phase prior to quiting all together.

I still don't like the low fuel PSI readings.....using the A/C gauge set not withstanding....book says 48 - 55 PSI in the KOEO test for both 1* & 2* pumps, and a 3 - 10 lb drop with the motor at idle speed as within specs. The f/f is an easy swap & might yield something, it's also the cheapest part in the fuel system! I know I tested my fuel PSI when I was having injector trouble and the difference between a new filter and the one that was in the car for 8K miles was dramatic, oh yea the OEM filter was still in my car when it was delivered.....a 15 yr old f/f is not my idea of good maintenance. I do it every yr along with some other stuff.

The regulator seems to either work or not, according to the FSM. Oh, the only variable is it's vacuum source....it is good or the hose is at fault. Check to see the hose is okay and that there is no fuel in the hose. Fuel in the hose is the tell tail that the regulator is kaput.


Tom