speeddemon

I have a 01' Suburban with a 5.3. It is 4 wheel drive and sees a lot of country roads. It is not beat on and maintained very well. The fuel pump has been replaced two times and I am still having problems. Sometimes first thing in the morning or other times in the middle of running errands it will not start. If I swap relays within the fuse panel under the hood it will fire right up. I have put a new relay in from NAPA and it still acts up. What could be hanging this relay up?
Thanks in advance
Shawn

EinST

I wouldn't think swapping relays proves anything unless the results are reproducible. Has the fuel pressure been verified to be 55-62 psi with key on, engine off?

speeddemon

Have had the fuel pressure checked at shop in the past. It was bad so the fuel pump was changed. Less than a month later it acted up on my wife downtown. It had been started and stopped half dozen times that day, then would not start, acted just like before. It would spin over fine but no start. I had her try it, no start. I then changed relays with one for the a/c I believe and it fired up and ran like nothing happened.

EinST

I'm sorry but the additional data you provided doesn't really point to the relay. It could be the relay socket or wiring underneath but then it could just be a coincidence or timing. There're a lot of things that can cause a non-start or delayed start problem.

speeddemon

I agree, after getting more of the story there has been a security light flashing on occasion. I agree that it is not the relay. Would it be the passcode stopping it?

EinST

Yours has Passlock. A flashing SECURITY indicator with key on means a problem in the theft-deterrent system, be it a Passlock sensor problem, tamper condition, BCM problem, etc. The fuel will be disabled while whatever the condition exists.

speeddemon

Thank you. As stated, it was just explained to me that the security light sometimes comes on while driving. I just go rescue her. If she waits it will eventually start.

EinST

Given the age of the vehicle, I would think it's the ignition switch. I'd either take it in for service or call a few automotive locksmiths around (since it's best to replace both the switch and lock cylinder at the same time). Good luck.

speeddemon

Thank you! Looks like that is my next project. I think that I should be able to tackle that.

EinST

You're quite welcome. I'd feel better if you had it properly diagnosed by a pro, though, since there's always a chance it could be something else.