Cranks, but won't start

[graffix000]

Hi all. I have an 2005 yukon denali with about 185k miles on it. I have a new issue that I am trying to figure out with it. Was driving normal, and all of a sudden it felt like it went into limp mode, and the vehicle shut off when driving without warning. No CEL or any light came on.

I was able to pull over, but the vehicle wouldn't restart. Just cranks. I tried switching the fuel pump relay with another but no change. I had it towed back to my place.

Weird thing was when I tried to re-start, the oil pressure was reading 0. There had never been any fluctuation in oil pressure prior. I did just change the oil the night before, so was strange for it to happen the next day. I checked the level and it was right at the top mark

I replaced the oil pressure sensor switch, but no change. It has a new fuel pump that worked for a few weeks prior to this incident, so do not think it is a fueling issue, and it sounds like the pump turns on when I initially turn the key in the ignition, but when I hooked up a gauge to the fuel line, it was not showing any pressure.

Any suggestions on what to look for next? I did read about the no oil pressure causing the fuel pump to not turn on as a fail safe.

Thanks in advance for any suggestions.

 

[Scottydoggs]

sounds like no fuel, could be a blown fuse. f/p builds when the key is turned to run, no way it knows about the oil pressure at that point.

so key to run, check fuel pressure, if you got nothing, you got a bad pump, or no power to it.

 

[graffix000]

sounds like no fuel, could be a blown fuse. f/p builds when the key is turned to run, no way it knows about the oil pressure at that point.

so key to run, check fuel pressure, if you got nothing, you got a bad pump, or no power to it.

Thanks, I too was thinking the same thing regarding the fuel pump. Just weird it was working properly, and then quit. Appreciate the input.

 

[Doubeleive]

yep, you have no fuel then, the engine would still start even if there was not a drop of oil in it, unless you had already ruined the engine.