1997 Chevy Suburban V8 Four Wheel Drive Automatic 169000 miles
Truck will not start on occassion, 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 asssembly and plug wires recently replaced. When it won't start the fuel pump does not run. Checked by no pressure/fuel at the shrader valve near the intake and got engineer to start by spraying carbuerator cleaner into the intake.
What are the probable causes for the fuel pump not running? What should I try replacing next?
Hi, thanks for the donation. Use a fuel pressure gage, engine cranking, see if any pressure. My hearing is no good, can't hear pump with engine cranking. My info shows an oil pressure switch in the fuel pump circuit, once you crank it enough to bring up oil pressure and the switch closes, the pump will run, even without the relay. Main voltage for fuel pump relay and o/p switch comes from ecm fuse, maybe fuse is blown.
Also, there is a fuel pump test connector, red wire with electrical connector, nothing plugged into it, if you run jumper wire from battery voltage, using inline fuse, to the connector, the pump should run, no need to use the key.
March, 9, 2010 AT 7:58 AM
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.
March, 9, 2010 AT 8:58 AM
The diagram below gives the location of fuel pump prime connector. According to our database. In case you can't read it, C8, under the hood, driverside fender lining, close to firewall.
I can't answer your question about the dual set-up, propane and gas, don't know.
April, 10, 2010 AT 3:11 PM
Any updates? I have a similar problem.
My truck has not started on two occasions, most recently yesterday. It starts later and is ok, but seems to crank a little longer before starting.
My system doesn't hold fuel pressure, with key on (but not running) pressure goes to 45 psi, but drops to below 10 psi in about 30 seconds.