My 2003 gmc sonoma 4.3 will crank over, but will not start. If I add fuel down the throttle body it will start and then shut off after the fuel is used up. I know I have spark. I cleaned the IAC and the map sensor. I also did a fuel pressure test. The results were 58 psi with ignition on and around 57 psi cranking. When I stopped cranking the engine the pressure stayed at 57 psi for more than 5 minutes. I'm thinking either a leaky fuel regulator, or fuel injectors, or even a vaccume leak? What do you think? Thank you in advance! Paul
I'd use a noid lite and check for injector pulse, engine cranking. The autostore sells a noid lite. Check for voltage at the injectors, key on, pink wire. That circuit is fuse protected.
December, 27, 2012 AT 5:13 PM
Ok thank you I will try that. I appreciate your time!
December, 27, 2012 AT 6:50 PM
No problem. Let us know what you find.
December, 27, 2012 AT 7:09 PM
I used my test light to check for voltage to the spider connector. There are 7 pink wires and all have power. I had someone crank the engine while I tested for a pulse on each wire. I got a pulse for each wire. The noid light doesn't connect to the spider connector. I could smell alot of fuel! I'm thinking fuel regulator is leaking? Thanks!
December, 27, 2012 AT 7:37 PM
I thought your fuel pressure looked good. Any applicable trouble codes? Check the coolant temp sensor.
Part of the fuel pressure test is to bleed pressure down to 10 psi, monitor the fuel gage for 5 minutes. If pressure drops more than 2 psi, replace the pressure regulator.
December, 27, 2012 AT 7:49 PM
I don't have a scan tool. So I can't check the codes. Can't afford a scan tool right now. I will check the coolant sensor. When I had the fuel pressure tester connected and stopped cranking. The pressure remained at 57 psi and didn't drop. Thanks again!
December, 27, 2012 AT 8:08 PM
Usually, obd2 code readers don't cost much? I understand money issues. I have the same problem.
December, 27, 2012 AT 8:24 PM
Ok my friend I will check that reader out. Thanks!
January, 8, 2013 AT 7:13 PM
Let us know what you find.
January, 8, 2013 AT 11:43 PM
I bought the code reader and no codes came up. I re checked the fuel pressure and it was below 50 psi. The first test was higher. So I'm going to change the fuel pump and filter. Thanks for getting back to me. Paul