Strange fuel pressure problem???!

[Boston GN]

Took the car out for a trip to a wedding. 100+ miles. Drove perfectly for the most part. I pulled in to a gas station to get directions and the car wanted to die. Wideband pegged at lean and stayed there. I was able to get the car to the destination and the problem seemed to have cleared up after a few minutes.
Drove the car back home. Again, fine on the highway, but once I started city driving after the 100 miles, same thing. Got it home, running extremely lean. Idling very rough like it wants to stall. Checked the fuel pressure and it's bouncing around then kind of settled around 15-20psi.
All numbers on the scanmaster looked fine except the O2 numbers which were very low as verified by the wideband. Did a quick check of all connections and everything looked great.
I shut it off and haven't looked at it.
This is a new fuel pump from racetronix. It might have about 500 miles on it. Think it could be that starting to die?
Any ideas?

 

[josh young]

Do you have a fuel pressure gauge in the car to see whats happening when it starts going crazy? That is low FP, I've always heard they needed more than that just to run.

 

[Boston GN]

The gauge is under hood, so I could only see it while it was stopped. At that time it was bouncing around crazy. Like a 15psi swing and then it finally settled after a couple minutes to around 15-20psi.

 

[John Larkin]

How is the voltage at when it's dying?

 

[dynoman]

Check voltage at the back of the car first , if OK , check grounds , then ALL connections all the way to the pump . Do you have a hot wire kit ? I was thinking split or leaking in-tank hose but that wouldn't come and go like electrical gremlins do !! Good luck, Sam

 

[Boston GN]

Haven't checked voltage yet when it was dying except via the scanmaster. It seemed fine there. I have the racetronix hot wire kit also. I'll recheck all of that.

 

[phil_jordan]

sounds like a faulty pump to me. I hope not seeing that you just bought it. Good luck and keep us posted

 

[Boston GN]

sounds like a faulty pump to me. I hope not seeing that you just bought it. Good luck and keep us posted

Unfortunately, this is what I'm starting to think too. I'll get to look at it better this weekend

 

[Boston GN]

Just went out to do a few more checks and all the wiring and grounds are great. Car fired right up and had good fuel pressure. Couldn't take it for a spin because it's raining. I let it run for a good 15 minutes and it seemed good. All numbers on the scanmaster were fine. Wideband looked good too. I didn't check voltage at the pump yet though
This car will be the death of me.

 

[87geeinn]

Fuel pump relay failing? Remember, the car still utilizes the stock relay wiring to trigger the pump even when hotwired.

 

[dynoman]

The Racetronix hot wire kit does not include the intermediate harness and bulk head connector up on the top of the tank , check those also.

 

[TurboBuRick]

Did you install a ground strap linking the tank to the body? It's important to ground the fuel tank to the body and the body to the battery.

From Racetronix:
REDUNDANT GROUNDING SYSTEM:
The Racetronix harness has a redundant ground upgrade as it is necessary to improve the pump's ground (-) supply as well. The Racetronix redundant ground upgrade clips onto the edge of the gas tank. Racetronix has integrated the harness ground into the main harness as a one piece assembly. The ground clip helps improve the tank and pump ground. All grounds (including the factory) are routed back to a common piercing ring terminal which provides direct ground from the large tank strap bolt and body. This provides superior clamping force and grounding. The weatherproof relay shares this mounting location so that no mounting holes must be drilled. Silicon grease is provided to coat the grounding clip and ring terminal in order to prevent corrosion.

Rick

 

[Boston GN]

Rick
Yes the tank strap is there along with another from the racetronix kit.
I find it strange that it only happened after the long trip. When it happened originally I kept pushing the car through it and it seemed to clear up. Then it happened the second time again only after a 100 mile trip.
I need to take it out again. I'm hoping to do it this weekend if the rain stops.

 

[earlbrown]

You said the scanmaster numbers looked fine. If you're losing fuel pressure, the INT's and BLM's should start creeping up to mask the issue. Once they hit their max, that's when the engine would actually start getting deprived of fuel.

I can't say for sure how an open loop idle chip like a TT would do. I would assume that with no correction a low pressure situaton would show itself immediately since there wouldn't be any ECM correction. (take that last bit with a grain of salt as I've never ran a TT chip, much less one with low pressure)

 

[Boston GN]

You said the scanmaster numbers looked fine. If you're losing fuel pressure, the INT's and BLM's should start creeping up to mask the issue. Once they hit their max, that's when the engine would actually start getting deprived of fuel.

I can't say for sure how an open loop idle chip like a TT would do. I would assume that with no correction a low pressure situaton would show itself immediately since there wouldn't be any ECM correction. (take that last bit with a grain of salt as I've never ran a TT chip, much less one with low pressure)

I do run a TT chip. The only thing I noticed through this whole fiasco was that the BLM crept up to 134 which didn't seem too bad to me considering how it was running and the wideband was at 19+
The last time I started the car (a few days ago when I finally had it home) it seemed to be a weak start, meaning the charge wasn't that strong. Wonder if my alt is on it's way out...

 

[earlbrown]

...or the battery, or the cables, or the connections, or the ground lead, or the starter.....

but that probably isn't the main factor in your running condition since the scanmaster is showing OK voltage while running.

 

[Boston GN]

Took the car out for a short jaunt this morning and it ran fine. Checked all wiring again and it all looks good. I hate when things like this happen. Oh well

 

[NY_GN]

Might have had a clog in the feed line that went away, dirty fuel?

 

[Boston GN]

It's strange that it happened twice only after a long trip. I'm wondering if either the pump or relay, after running for quite some time and heating up starts to fail. I'm not even sure that makes sense, but the car has been running fine recently.
I'm going to swap out the fuel pump relay just as preventative maintenance. I have no idea where to else to look

 

[NY_GN]

Relay sounds like a good start. I got some bad fuel, then after my pump shit the bed, I checked lines before hooking up new pump....filthy.