Fuel Problem

[luisito320]

i been having fuel problem were my fuel pressure drop when the car is at idle for while. i have replaced the ITFP with DW300, IT fuel pressure regulator, HPFP switch from autotech to Corksport, also change the relief valve. all is done between 2 to 3 week apart.
i attached a log on idle, hope this help.

[5doorsoffury]

What does it drop to 60psi? Have you checked your spill valve and HPFP internals? They could be sticking.
Edit just checked the log it looks like the internals are sticking. Pull the pump and clean it out and check it

[luisito320]

the internals are brand new. and spill valve is clean.

[luisito320]

I will be replacing the fuel pressure sensor. Cuz going to basics and use the relief valve diagnostic the fuel pressure doesn't go up again. And it should go up since the car is still hot and the relief valve is brand new.

[luisito320]

So today I spend like 5 hours looking at wiring diagrams and doing diagnostics. I turn out that when the car gets to normal driving temperature the ECU cut the signal to the fuel pump relays.
Now I have to figure out if the ECU is bad or there is another sensor causing problems.

[luisito320]

So ECU is good.

Cleaning mechanical pump again.

[luisito320]

Fuel still drops and shut off. Even with the ITFP connected directly to the battery.

[luisito320]

Found what was causing the fuel drop. Problem solve.

[Jeff23spl]

Originally Posted by luisito320 Found what was causing the fuel drop. Problem solve.

what was it?

[luisito320]

ITFP was getting hot and is was losing pressure slowly.

[MSMS3]

Originally Posted by luisito320 ITFP was getting hot and is was losing pressure slowly.

So you replaced it, or found out what was making it over heat and fixed that, or what?

[luisito320]

I did replace it. Still dont know why it was overheating. I think the pump was bad, because I check all wires trying to figure out what was wrong with it and everything is good.