4.6 Northstar experts? Hard start problem

[Roc87]

Wifes '97 STS has had a problem with starting ever since we bought it. I've replaced the fuel pump, replaced the fuel filter, changed plugs, air filter, checked fuel pump relay, etc... Sometimes it even backfires through the intake when trying to start. Once it's started, it runs fine and gets average mileage. Anybody with any ideas? Cam(s) sensor? Crank sensor? I'm ready to sell it!!!!

 

[Lee_Burough]

Sometimes its the basics that sneak up and bite us

I bought my 94 SLS Northstar 11 months ago with 65k on it. It had a subtle miss at idle. Sometimes slow to start (not exactly hard starting). I did everything I could think of, then, took it to a trusted shop. Their scope showed everything just fine, but they changed the lugs anyway.

It ran pretty well for a few days and started missing again. I put an ohm meter on the plug wires and found two with an open circuit. New plug wires cleared it up just fine.

You may not need plug wires. But, it may be something basic like that. A bad ground, bad connection, bad oil pressure switch....Something simple. Once, I ended up cleaning the battery terminals to cure a problem....Trouble was, I did that after a bunch of other things that ended up being a waste of time.

Good Luck

 

[Scott Atk]

I can tell you with 98.7% certainty that you need a new fuel pressure regulator. They are notorious. Symptoms are long crank times, otherwise run fine. They are around 50.00 at Autozone. Don't bother going to the dealer the GM ones aren't any better than the aftermarkets. They go out like clockwork around 50 - 60K. HTH,

 

[Shane]

www.cadillacforums.com

 

[TurboJim]

Originally posted by Scott Atk
I can tell you with 98.7% certainty that you need a new fuel pressure regulator. They are notorious. Symptoms are long crank times, otherwise run fine. They are around 50.00 at Autozone. Don't bother going to the dealer the GM ones aren't any better than the aftermarkets. They go out like clockwork around 50 - 60K. HTH,

Yup, I agree. Have also seen some injectors lock open and hydroloc the motor. Boy, who is the a-hole designed that plastic fuel rail anyway...

 

[Roc87]

FPR

Dang you guys, Buick, cadillac, it doesn't matter, you can figure it all out, I'm going to stop taking the car in for any diagnostics! I pulled the vacuum line off the FPR and it started spitting gas out, almost spraying it out. Thanks for the suggestions!!!!