RedChevy44
Newbie
I recently purchased a 1996 Suburban Vortec 454 that has had nothing but issues. I have spent more time wrenching on it than I have driving it. I put about 1300 miles on it right after I bought it and it ran fine. Then I let my relatives borrow it to go to California to pick up their mother and some furniture. They were towing a trailer up the pass between Baker and Las Vegas when they smelled something burning and looked down to see the carpet was smoldering. The engine was missing and they kept pushing it until they had the catalytic converter hot enough to start the carpet on fire (there is a heat shield between the floor and the cat, it must have been glowing red!). I put it on a trailer and towed it home. I had read about how the factory injectors were problematic and figured one of them must have stuck open. First thing I did was a compression test to make sure the engine was OK. All cylinders tested 140-150 PSI. My UOA had come back showing antifreeze in the oil (no surprise on a high mile vortec) so I planned on replacing the intake manifold gaskets while I was there. The next weekend I tore into it and replaced the intake gaskets, injectors (new Bosch injectors from Five-O Motorsports), new AC Delco fuel pressure regulator, new cap-rotor-wires-plugs (good parts, not "cheap" parts), and thermostat. The old fuel pressure regulator was leaking fuel out of it and the vacuum hose that connects it to the intake manifold was MIA. I put it all together and found that the PCV valve was missing so I bought a new one and installed it. I went to start it and it wouldn't start. The next weekend I started to diagnose it and found that it was blowing the ENG1 fuse. I thought that it was the wiring to the passenger side rear O2 sensor since all the insulation had melted off of the wires clear up to the cross member behind the transfercase. I cut out the bad section of wire and insulated the wire ends. It was still blowing the fuse. Finally found that the crank position sensor wires were missing insulation for about 2 inches behind the connector and we're touching each other and shorting out. I taped up the wires and ordered a repair pigtail. I started it up and it seemed to run fine. The next weekend I worked on the exhaust system. I replaced the passenger side cat, the drivers side was just fine.
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I also replaced the muffler since it apparently had a backfire that split the seam on it. I also replaced both pre-cat O2 sensors and the drivers side post-cat O2 (still haven't fixed the wiring). I also changed the fuel filter while I was under there. I test drove the suburban, and the longer it ran the worse it ran until it died and wouldn't restart. About a half hour later it restarted and did the same thing. The next weekend it wouldn't start at all. I had ordered an AC Delco crank position sensor so I installed it. It still wouldn't start and I found that there was no spark. I checked part numbers and found that the coil and ignition control module was the same one I have on my 350 Vortec. I swapped the ICM first and it started and ran. I test drove it and it ran without issues. 2 weeks later I take it out of town for Thanksgiving. It runs fine all the way there but then intermittently runs like crap for the next 2 days. I put a fuel pressure gauge on it and found that it was at 50 instead of the specified 56-62. I ordered a Delphi fuel pump and installed it. I changed the fuel filter again. I had a hose hooked up to the test port and jumped the fuel pump relay. Fuel was barely dripping out. I had cleaned the ground for the new fuel pump when I installed it. I checked it anyways and it was a good ground. I checked voltage at the pump and it was 13.5 volts (I had a battery charger hooked up). I ran a separate ground and power wire straight to the pump but it didn't make a difference. I hooked it back up and pinched the return line to see if it made a difference and it made a little bit of a difference but then I must have blown an injector out of the rail because gas started running down the engine onto me. That was late last Saturday and I haven't had a chance to take the plenum back off and check it out. My question is why am I not getting the fuel I need? Do you think I got a bad FPR?
. Guess it's time to look for a GM hydro boost.
