Low fuel pressure issues

[RAPID]

I've had a lean condition for almost a year that has now gotten worse.  The CEL will not stay cleared and flashes sometimes. The code says Lean - both banks. The car stumbles. A mechanic read the fuel pressure at the rail as 52 PSI.
It's a FD with a '01 LS1, mostly stock. It's got a Denso 290 gph pump, powered by the harness. A GM fuel filter/FPR feeding one of the stock FD lines to the fuel rail.
My question to you guys is what should I try first to fix the problem ?

[usmcpi]

injectors in good condition?

[nzgreenfox]

If it was only an injector problem then the fuel pressure would be OK. I had a similiar problem on my car and it was due to the poor Mazda wiring. Try this

1. With the car cold and a fire extinguisher near by disconnect the fuel line at theinjectors.  place the fuel line in a large container and run the pump for a minute. To do this switch the ignition on and power your pump relay.  Measure the amount of fuel collected over the one minute period.

2. Reconnect the fuel line and check fo leaks. Start your car and measure the volts and amps the pump is drawing. To measure the current remove the fuel pump fuses and connect the multimeter across it.  to measure the voltage splice into the power cable on top of the tank , connect your multimeter between the power cable and earth.

Wait for the car to cool down. Disconnect the battery. Run a cable  from your battery positive in series with an amp meter and splice into the power cable to your pump near the top of the tank. Reconnect the battery you should hear the pump start. Repeat step 1 above,   Compare the volume of fuel pumped.

Compare the voltage as before. To compare the current you will need a second multimeter across the fuse. If running this jumper from the battery increases the fuel volume ( and the voltage and current) then you will have to rewire the pump.

http://www.rx7club.com/showthread.php?t=773489
has a diagram of a possible solution about half way down the thread. But a warning.  In this set up if the relay jams on your pump will stay running.

[usmcpi]

Slightly OT, but when my key is in the ON position (position key is in when car is running, but without the car running) my fuel pump just keeps running.  Isn't it supposed to prime itself for a couple seconds then shutoff till you go to start the car?

[theantirotor]

Slightly OT, but when my key is in the ON position (position key is in when car is running, but without the car running) my fuel pump just keeps running.  Isn't it supposed to prime itself for a couple seconds then shutoff till you go to start the car?

if it is controlled by the pcm, yes.  if it is just hotwired, it will do what you are talking about.

[RAPID]

Thanx for that advice nzgreenfox. I'll try it on my next day off. Still. I've got 30K on the swap and this developed over the last 5k. Could providing the pump less current than needed damage the pump ?
If I do have to replace the pump I want to get a Bosch 044. Can anyone tell me what amp relay I would need to run it ? Can anyone tell me a good place to buy a replacement GM FPR  and the part # ?

[BeatTheTunaUp]

It's weird that it just started over the past 5k miles but functioned with the key properly before that.  Unless someone messed with your wiring in between, I'd say you had a high gate blow on the ecu, and it's allowing voltage across it as soon as the ecu gets power.  Hence the on all the time issue.  I ran a 30 amp relay for a while and it worked, but I eventually went to the junk yard and snagged a beefy  relay with 10 gauge wire in/out from under the hood of a car.  And for the vette FPR, any parts store will have it for around $90.

http://www.autozone.com/autozone/parts/Az-Filters-Fuel-Filter/1999-Chevrolet-Corvette/_/N-jd52hZ8gd7g?itemIdentifier=947237_0_0_