I drove my car Monday, parked it with no issues. Downloaded new tune yesterday. I dont recall if i heard the fuel pump running or not when I cycled the key on.

I went to drive it to work this morning and definitely noticed the fuel pump was not running. Attempted to start anyway and of course it just turned over, no fire. Fuel pressure gauge is showing 4 psig.

So I had a about 10 minutes to troubleshoot before I threw everything in my truck and left for work.

My setup: I'm assuming stock fuel pump (101k miles) with racetronix firewire and KB BAP.

I checked the fuse on the firewire - its good. I checked fuse for the fuel pump and its good. I switched relays with another, no help.

I then pulled the relay for the fuel pump and verified 12V when testing from 85 to 86 (which should verify good ground and power from PCM).

I also had 12v at 30.

I jumpered the relay (from 30 to 87) and I hear the fuel pump click once, but never run.

I checked codes and found nothing current, all H. Didnt have time to write them all down.

Is my problem the fuel pump, or should I be looking at the BAP first?

 

Thanks for the response. Didnt know if it was possible that the BAP could "short circuit" or if it defaulted to 12v to the fuel pump. Especially since I can hear the FP click. I will get in the rear fender well and check it this weekend.

 

Ok, this is really strange. I came home this afternoon, turned the key on and the fuel pump came on. Car started right up with 60 psig fuel pressure and didnt miss a beat.

WTH?!?!?!

 

So I checked the grounds at the BAP and fuel pump this weekend. I made sure they were making good connection. I put the key in and turned ignition on prolly 15 times this weekend. And the fuel pump ran every time.

So i started driving it this week. I drove it the last 3 days. Never missed a beat.

And as I type this, I'm sitting at the post office broke down. No fuel pressure. I can hear the click, but fuel pump is not running.

Im thinking I'm gonna buy the racetronix fuel pump and try that.

SOS. Please send help. Lol

 

And it just gets crazier. Went to pick it up this afternoon and tried key on first. fuel pump runs and engine runs. I drove it home and parked it on ramps/jacks.

I cant troubleshoot if there's nothing wrong with it. I guess I'm gonna throw a racetronix fuel pump at it and see if that fixes it.

 

I've already bought a fuel pump. It's time to replace it anyway at 102k miles. But yeah, after I get it replaced I am going to try that.

Additionally, I found there is a relay on the FireWire kit. I'm thinking that might be the problem. Pretty sure it's not a ground.

 

SO i replaced the fuel pump on Wednesday with the racetronix unit. I started the car up right after that and it was making good fuel pressure. This fuel pump is MUCH quieter. I can barely hear it run whereas the stock unit was quite loud.

I left a battery charger on it all evening because without driving it the battery goes dead for a few days.

I went to check it today and no fuel pump, no fuel pressure. So i started troubleshooting, I jumpered the relay and was getting 12V to the rear harness that plugs into the fuel pump (actually it plugs into the racetronix harness now). I was getting 12V to the BAP, but nothing out of it back to the fuel pump.

Can the BAP stop working intermittently???

 

Some other thoughts: I bypass the BAP and the firewire kit by plugging in the factory harness to the fuel pump and the fuel pump runs.

I recently pressure tested my boost piping by pressuring up through the brake booster line. I wonder if I somehow messed up the hobbs switch. How can I test it?

 

Well, I identified the problem finally. Unfortunately, in the process I purchased a BAP that I didnt need.

I installed the new BAP yesterday, and the fuel pump still wasnt working. however, I was getting 12V into the BAP, but nothing out.

So i changed the hobbs switch out. Same thing.

I reached down and touched the fuse/wiring for the Racetronix harness where it comes off the alternator and the fuel pump starts working again.




How the hell can I get 12V to the BAP but not enough current to run it and fix the problem just by touching the wiring?

Anyone want to buy a boost a pump?