I finally get GN #2 back from shop after 7mos. this is the 4.1 that i had re-built due to crank bearing failure. forged pistons were installed ( i hope ). anyways, I have had to re-do the motor vaccum lines, and the gauges inside- water temp-pyro-oil etc...etc...this time I mounted them in the dash. as some prick had broken into the shop and cut all the gauge wires and took the gauges. long story behind who did it, but i know who did it. so I was driving and GN stalled out on me. I noticed that fuel gauge would read then not read. I changed out the FP relay and I think that helped, but I noticed that fuel pressure begins to drop after I reach 5lbs of boost. I will do the troubleshooting for fuel delivery, but what else should I check?
fuel pressure drops......
- Thread starter NOTSOFAST
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Are you saying the "fuel gauge" or the a fuel pressure gauge? If it's the fuel gauge, it may be a bad ground or the sending unit may be going. If it's a f/p gauge, it may be signalling a f/pump failure in which case you will be running lean. Not good.
I believe my fuel pump is on its way out. today after my son and I took GN out. after about an hour of running errands it turned off again. luckly we were pulling into the driveway. after a few hours of cool down it started right up. can this happen if it sat untouched for 5mos? vaccum lines are good, but after I accelrate I get a strong smell of gas. I checked for leaks but didn't locate any from the fuel lines, starting at fuel filter to fuel rails.
That is a HORRIBLE way to troubleshoot! Remember that scene in Pulp Fiction where Marsellus Wallace didn't want to think, he wanted to KNOW?
To know if your fuel pump is going out all you need is a FP gauge taped to the winshield with a boost gauge to compare it to. If it can't keep up, it's bad. Period. (and not the new version of period. The correct one)
Smelling gas would be the path to follow. We used a sealed fuel system so any signs of raw fuel is the place to focus on. Do you still have a charcoal canister?
Earl, I have already noticed that fuel pressure does not rise with boost. I have an electric fuel presssure gauge right by my boost gauge on the a pilar. I do still have the charcoal canister. looking to order a new walbro 340. did they ever fix the issue's they were having with the bad batch that came out a few years back? it's been a while since iv'e had to do the pump.
I have mixed results with the Walbro. I'm trying a DW pump next. Supposed to be a very nice pump, but without the fuel pressure issues at idle that a few experience with the 340 pumps. I think the DW is a 320lph pump and it slows down at low need to keep idle pressure regulated well; if I understand their propaganda properly.
AssUming your gauge is correct, you have a fuel pump problem, a line problem, a power problem, an FPR problem or a vacuum/bost signal problem.
That HAS to be taken care of 100% before driving the car.
Well, it didn't do this before I had motor pulled and re-built. 5mos of fuel pump being dry can cause havoc on a good pump, as its not getting lubricated. But, I have checked all else... vaccum hose, fpr, and the gauge going down on acceleration is biggest indicater of bad fuel pump. Luckly I don't horse beat my ,GN's, so as to cause further damage.
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