Carl Eagle Posted October 14, 2011 Report Share Posted October 14, 2011 I recently bought a 2001 GMC Sierra C3 that is a previous water damage vehicle. I have replaced the gas tank, fuel pump, fuel filter, flushed the fuel lines and I cant get it to run. It threw a couple codes but they are only the oxygen sensors. If you spray some starting fluid back in the intake it will start and then shut off. I know it is firing and getting fuel to the fuel rail but I dont think the injectors are working. I replaced the injectors also and still no luck. What could the problem be? I have also checked all the fuses in the truck and all are ok. Oh and the water damage was just about 4 inches high in the cab so the whole truck wasnt underwater...Thanks in advance. Carl Quote Link to comment Share on other sites More sharing options...
2001silverado364 Posted October 14, 2011 Report Share Posted October 14, 2011 (edited) Have you checked for fire(voltage) at the injectors? Edited October 14, 2011 by 2001silverado364 (see edit history) Quote Link to comment Share on other sites More sharing options...
Carl Eagle Posted October 14, 2011 Author Report Share Posted October 14, 2011 Would I just use a simple test light? Quote Link to comment Share on other sites More sharing options...
2001silverado364 Posted October 14, 2011 Report Share Posted October 14, 2011 Yeah a test light on the injectors wires and crank the engine. You should get pulses of 12 volts. Quote Link to comment Share on other sites More sharing options...
Carl Eagle Posted October 14, 2011 Author Report Share Posted October 14, 2011 Ok, ill go try it and see what I come up with. Quote Link to comment Share on other sites More sharing options...
Carl Eagle Posted October 14, 2011 Author Report Share Posted October 14, 2011 It does have fire at the injectors, I dont see why it will not run... Quote Link to comment Share on other sites More sharing options...
Carl Eagle Posted October 14, 2011 Author Report Share Posted October 14, 2011 When I first replaced the fuel pump it would barely run...it would rev up to 4500rpms but it sounded like it was running on 4 cylinders. Could the cats be clogged up and cause it not to run at all. When I started it and let it sit and idle for about 5 to 10 minutes the exhaust got really hot. I mean hot enough to wilt the grass under the truck. Quote Link to comment Share on other sites More sharing options...
2001silverado364 Posted October 14, 2011 Report Share Posted October 14, 2011 (edited) Does it start at all? Run for a minute? Also did you put the intake back on after you sprayed either in it, cause they don't like to run without air going thru the maf. If you think the cats are clogged you can pull the o2's, it'll run without those just really rich. I don't see clogged cats preventing it from starting though. Edited October 14, 2011 by 2001silverado364 (see edit history) Quote Link to comment Share on other sites More sharing options...
Carl Eagle Posted October 14, 2011 Author Report Share Posted October 14, 2011 you can spray starting fluid back in the throttle body and it will start and idle for about 20 sec and then it will shut off. And yes with the intake back on it. Quote Link to comment Share on other sites More sharing options...
Carl Eagle Posted October 14, 2011 Author Report Share Posted October 14, 2011 I figured if the cats were clogged up it would atleast start...I dont know what else to check. How much fuel pressure should it have? Quote Link to comment Share on other sites More sharing options...
2001silverado364 Posted October 14, 2011 Report Share Posted October 14, 2011 (edited) You say you've pressure tested the fuel rail? Keyed on and not trying to start 60 psi is probably on the higher side of the spec, but around that. Edited October 14, 2011 by 2001silverado364 (see edit history) Quote Link to comment Share on other sites More sharing options...
Carl Eagle Posted October 14, 2011 Author Report Share Posted October 14, 2011 (edited) No I dont have a pressure tester, but it has a new fuel pump in it. Guess ill be making a trip to the parts house. Edited October 14, 2011 by Carls LQ9 SS (see edit history) Quote Link to comment Share on other sites More sharing options...
2001silverado364 Posted October 14, 2011 Report Share Posted October 14, 2011 It wouldn't be the first time a new fuel pump is bad, but definitely very rare. Probably a good idea to look at and inspect the regulator as well. Quote Link to comment Share on other sites More sharing options...
Carl Eagle Posted October 14, 2011 Author Report Share Posted October 14, 2011 I have a parts truck that ran really good. I took the tank and all off of it and still no good. Then I put the new pump back in the truck. Where is the pressure regulator? Quote Link to comment Share on other sites More sharing options...
2001silverado364 Posted October 14, 2011 Report Share Posted October 14, 2011 left side of the intake manifold, it has a tiny vacuum line running to it. here's a pic. Quote Link to comment Share on other sites More sharing options...
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