j0hn_j0hn08

iTrader: (1)

Hi all so i finally decided to bite the bullet and remove my fuel pump to see what the car was equipped with and troubleshoot a cold start issue where the car takes longer than usual to start.

So i pulled the Fuel pump and i found that the car has a Racetronix RXP252T.





See link for specs
http://www.racetronix.biz/customkiti...sp?kc=RFPK-001











One thing i noticed was that the car is still using the stock harness and there is no aftermarket "hot wire" harness used like recommended by Racetronix. See link for Harness info
http://www.racetronix.biz/customkiti...=FPWK-017W&eq=


While examining the Fuel pressure regulator i noticed that there is no hose attached to the fitting that comes off the top of it.

Is there supposed to be a hose that goes from the FPR to somewhere else? or is it supposed to be opened like that?

See photo






I also found a small kink in the clear line that runs from the fitting on the fuel pump to the vacuum fitting on the bottom of the fuel pump casing, could this cause any hard start issues? Can anyone explain what that hose and fitting do exactly?


So i am thinking about ordering the the Hot wire harness to see if the added voltage would improve the pump and eliminate the hard start issue that im getting. Im guessing the previous owner did not want spend the extra money for the harness.

is there any way of testing the FPR with the pump out?

_JB_

iTrader: (33)

No hose should be attached to the fuel pressure regulator. Have you hooked up a fuel pressure gauge to see what's going on?

zeeman99

Check valve in pump may be bad and pressure is bleeding down. Easy to check with a fuel pressure guage.

j0hn_j0hn08

iTrader: (1)

Is the check valve inside the pump itself? meaning the whole pump would need to be replaced? Pump was dated 2014, so its probably about 2 years old.

_JB_

iTrader: (33)

Check valve is in the pump. Before you start tearing **** apart have you hooked up a fuel pressure gauge? They are probably the best aftermarket gauge you can add.

j0hn_j0hn08

iTrader: (1)

No i havent, i had multiple issues,

My car was hard starting every crank and after swapping the iginition relay i thought i had completely fixed the issue. Turned out that the issue was still there but hard starts were no longer happening on every single crank, they were now only on a cold start crank or after the car sat for about 15 minutes.

I figured out that setting the key forward to on and off about 3 times prior to cranking caused the car to start perfectly.

So far i replaced the fuel filter and ignition relay.

The P.O had cut an access panel in the trunk area for the Fuel pump and it was easy to pull out the pump.

Ive ordered a new regulator from rock auto and a new pump from racetronix (same 255lph pump) which i expect sometime next week, would i have to open up the pump to check the check valve? at this point im thinking its the pump since the regulator and its o-ring looks intact, figured since the set up was out already might as well replace it. Also installing the "hotwire" harness suggested by racetronix.

I will probably be really upset if the issue persists after throwing these parts at it, but im not sure what else would be left to check?

1 FMF

iTrader: (1)

if you put a fuel pressure gauge on the fuel rail on the engine, you will immediately know if the pump is at least providing the correct ~50 psi prior to starting and during idling. that would be step 1 for diagnosing the fuel pump, at this point you are foolish if you do anything else.

if you have adequate fuel pressure during engine cranking and the motor is not firing then it's not the fuel pump.

If it takes cycling of the ignition key 3 times to get the fuel pump to provide correct fuel pressure to the fuel rail... which will be shown on your pressure gauge... then i would suspect faulty pump. But unless you have a fuel leak and the system leaked out, with ignition key turned on the 1st time that within 1/2 second you will have 50 psi at the fuel rail. This takes no electrical power to accomplish, so adding a hot wire harness or whatever it's called is not going to help, not at this point in the game trying to get the car started.
If you're running wide open throttle 5 seconds after launching the car and the engine stumbles because lack of fuel pressure because the fuel pump can't keep up with demand, then that's a different story... but your problem is starting the engine. And it's not the fuel filter, not for starting the engine.

being a used car and the previous owner (owners ? ) have at least put an aftermarket fuel pump in it would not surprise me if the engine computer has been reprogrammed (i.e. tuned) and tuned poorly which I would bet is the cause of your no start / hard start problems.

komik

iTrader: (7)

+1 on running a gauge at the rail.

-1 on suggesting the ECM has a bad tune simply because the fuel pump was replaced. GM fuel pumps fail constantly. I have replaced them in a Trans Am, a Grand Prix, and a Sonoma without modifying the ECM's.

When the stock pump failed on my '00 T/A, I replaced it with a Racetronix pump, but still used the factory wiring instead of bothering with running the harness supplied with the pump. (Though I did mine by dropping the tank versus cutting a hole.) The car was hit by a truck not long after that, so I can't testify to the longevity of Racetronix pumps.

Monello

iTrader: (1)

Did you ever get this figured out?