usmcsni

when reading the Fuel pump duty cycle with an SCT TSX whats the normal reading for an 02 GT that has a JLT CAI

cliffyk

If it is reading the PID 1673 (IIRC) it should be 5% to 50% depending in engine speed/load/etc.

The PCM sends a 5% to 50% duty cycle to the fuel pump driver module which then powers the pump at 10% to 100% of full capacity. The FPDM returns a 50% d/c signal to the PCM to indicate all is well.

Signals from the PCM of 0% to 5%, 51% to 67.5%, or 82.5% to 100% are invalid, the FPDM will return a 25% d/c signal to the PCM.

A PCM signal of 67.5 to 82.5% command the fuel pump off, the FPDM will return a 50% d/c signal to the PCM.

usmcsni

My Tuner is showing .35 to .45 at WOT is that normal as im getting a pinging problem and its reading FPDC

cliffyk

That is 70% to 90% and is typical, the pump never runs at 100% on an otherwise stock engine. What is "reading FPDC", a DTC--if so, what is the code?

usmcsni

FPDC-Fuel Pump Duty Cycle as in the PID. lol sorry

cliffyk

Then what your are seeing is normal, Pinging can be caused by too lean a air/fuel mix, too advanced ignition timing, and/or one more "hot spots" in the combustion chamber (including plugs that are too "hot".

You need to monitor the fuel pressure, timing, and AFR (a wide band O2 system is needed for this) to determine the actual cause or causes.