fjdavid

I have a 99 Suburban that I’m having no start issues. The engine turns over very well but doesn’t even try to start or catch. The fuel pump had died and I confirmed with a fuel pressure gauge. I replaced the fuel relay and the fuel pump on Sunday. It ran like normal and I drove it around a while to be sure it would be fine under hard acceleration and high speeds. My wife then drive it several places Monday with no issues. Tuesday morning she couldn’t start it. I checked fuel pressure and it was high 50’s psi. I suspected the ignition module and replaced it and the coil just for good measure. No start and I smell gas at the exhaust. I checked the crankcase sensor and it was not getting a signal, so I removed it and it fell apart. So I Replaced the crank sensor and no start again. I replaced the cam position sensor as well and still it didn’t start. I’m at a loss now since I believe I’ve replaced all the sensors that are associated with the ignition and timing.

The injectors were replaced with the newer style injector spider in 2008. Cap, rotor and spark plugs were replaced last year. Any ideas or other things to check would be greatly appreciated.
Frank

in2pro

Have you verified spark at the plug...

fjdavid

Yes, I checked spark at the number one cylinder and coming out of the coil

shamrock246

did you try the old coil again i had a toyota camry do this to me it would have spark on the tester but it would not fire in the cylinder after replacing the coil it ran maybe that new coil wasnt the best,did the plugs become fouled and need to be cleaned?


Sean
97 4x4 burb

fjdavid

Its been raining alot this weekend and again today. I have to work in the driveway so I'll check the coils when the weather breaks. Someone this weekend told me that the wiring harness could have a broken/intermitant connection somewhere in the harness. Not sure how to check that other then start tracing wires and looking for broken/damages wires. anyone have any issues with the harness or connectors?

fjdavid

Well, the rain stopped and I was able to check compression on the engine. cylinder 3 and 4 both had wet plugs. Wet with antifreeze. when I turned over the engine they pumped out some antifreeze. I guess both heads decided to blow gaskets at the same time. Would that prevent the engine from firing?? I've driven cars with a blown head gasket pumping steam from the exhaust just to get it home. but that was a late 80's car. would a wet O2 sensor prevent correct fuel mixture and prevent the engine from even trying to start and sputter?

Looks like a head job before I can determine if I need to replace the ECM.

thanks,

fjdavid

well, it turns out that both cylinder heads had a crack in the second cylinder back from the front into the water jacket. what are the odds of that? anyway, I'm replacing them today and hopefully it will start up once I put it all back together.

David99

99 suburban no start i have spark and fuel.

David99

i have a 99 suburban wont start . I have 55 psi fuel pressure and i have spark in all cylinders, replaced ckp,wires,spark plugs,ignition coil,ignition module,fuel pressure regulator. i checked timing and all grounds. sounds like it wants to start and it diesels. i sprayed starter fluid in the intake not even a sputter wich means not fuel problem.
Dont know what else to do.