done everything else i can think of...fuel pump?
10-27-2008, 04:29 PM
#1
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done everything else i can think of...fuel pump? well, over the last three years the racetronix pump (and harness) has gradually gone from 62 psi at idle to now 57 psi at idle. Sometimes it idles at 58 or 59 when it's cold and at first start up. On top of that, even reving to 3k rpm the fuel pressure drops 2 psi. At WOT, the pressure drops to 49 psi.
I've changed the filter, and stock fuel pressure regulator (intank, I found a site that sells them separate from the whole assembly). I checked the voltage at the pump. I stripped wire off the pos./neg. and used alligator clips to get the voltage with my multimeter. Voltage from idle to WOT is 13.6 to 13.8 Volts.
I thought the problem might be electrical. The battery is almost a year old so I think that it's okay. There don't appear to be any charging problems. The car starts perfectly and lights, and stereo (2 amps, sub, aftermarket speakers) run fine.
All this leads me to think the pump is going out. It has 25k-30k miles on it. The good voltage at WOT and the fact that the idle pressure has gradually decreased over the last 3 years leads me to think it's the pump. Does this sound right?
thanks!
I've changed the filter, and stock fuel pressure regulator (intank, I found a site that sells them separate from the whole assembly). I checked the voltage at the pump. I stripped wire off the pos./neg. and used alligator clips to get the voltage with my multimeter. Voltage from idle to WOT is 13.6 to 13.8 Volts.
I thought the problem might be electrical. The battery is almost a year old so I think that it's okay. There don't appear to be any charging problems. The car starts perfectly and lights, and stereo (2 amps, sub, aftermarket speakers) run fine.
All this leads me to think the pump is going out. It has 25k-30k miles on it. The good voltage at WOT and the fact that the idle pressure has gradually decreased over the last 3 years leads me to think it's the pump. Does this sound right?
thanks!
10-27-2008, 06:05 PM
#2
Seeing that the idle pressure is down, the filter is not likely the cause.
Even though the idle pressure was 62, it should be 58. This was due to the larger pump overloading the stock regulator at idle.
If your pressure is now lower, either the pump is getting weak, or there is an internal leak at the fuel hose or somewhere else in the tank.
Does your pressure hold once you shut the car off?
Does the pump prime & does the car start easily?
Even though the idle pressure was 62, it should be 58. This was due to the larger pump overloading the stock regulator at idle.
If your pressure is now lower, either the pump is getting weak, or there is an internal leak at the fuel hose or somewhere else in the tank.
Does your pressure hold once you shut the car off?
Does the pump prime & does the car start easily?
10-27-2008, 08:07 PM
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oh I forgot to mention, I also replaced the intank fuel hose. The pump primes to about 43psi and holds (after replacing the hose). I have no problems starting the car. A few weeks back, the car would refuse to start but I traced it down to a loose connection where the racetronix harness is hooked up to the battery. The second bolt on the post extender had backed out causing the ring terminal to intermittently lose contact. The car wouldn't start unless you kept cranking it over (causing the terminal to regain connection). I wonder, could this bad connection possibly have shortened the life of the pump?
