Electrical problem V8 Four Wheel Drive Automatic 169000 miles
Truck will not start on occasion, mostly first thing in the morning. Later in the day it will start and run fine. One time I drove 25 miles into town and it wouldn't start after stopping at a parts store. Have replaced the entire fuel pump assembly with OEM dephi pump; replaced fuel pump relay; fuel filter, entire intake injection assembly and plug wires recently replaced. When it won't start the fuel pump does not run. Checked by no pressure/fuel at the valve near the intake and got engineer to start by spraying carburetor cleaner into the intake.
What are the probable causes for the fuel pump not running? What should I try replacing next?
I can't find the red wire for the fuel pump test connector. Please be more specific on where to find it.
Also, my vehicle is equipped to run on propane gas as well as gasoline. Could the additional electrical module added under the ECM have anything to do with my problems with the fuel pump not running intermittently?
The suburban is currently running so it is hard figure out what is wrong. Two days ago it wouldn't start early in the morning, but ran fine later in the morning and has run fine ever since. I expect it will not start at sometime in the future and I want to be prepared. If I make up a jumper wire for the pump test connector a head of time at least I will have the capability to get it running in short order.
Wednesday, January 8th, 2020 AT 12:42 PM