I have been chasing a fuel economy problem for quite some time and now it has finally given a bad symptom and turned into the engine running as if it is misfiring. Fuel economy was at 8mpg in town and 14mpg hwy before it got worse (see below).
The engine is being flooded with an unusually high amount of LIQUID FUEL (not VAPOR). It is enough to leak out onto the pavement (See below).
However, the PCM wiring harness was melted/damaged and several of the wires had to be pulled apart and repaired individually. This was due to a tech routing the harness over the EGR pipe, which in turn constantly kept re-melting it every time it was driven. This has since been rectified.
Gas was/is leaking out of the front bank exhaust manifold & down-ypipe junction and can be seen on the pavement in a 3 - 5 inch puddle. I do not run the vehicle on the road. This was discovered in the driveway one day on startup and I immediately shut it off.
After intense analysis I have discovered with a Fuel Pressure Gauge that the system is not holding Fuel Pressure AT ALL even with KOEO (Key On Engine Off) and I witness it fall extremely fast to ZERO in this state.
I recently installed new spark plugs to see if this would help and ALL OF THE PLUGS were JET SMOOTH BLACK and were only 10k miles old.
The injector wiring harness has been continuity and resistance tested to be OK too.
QUESTION IS: Is it likely the PCM is fried since we know the wiring has been repaired, regrounded everywhere, etc. Under hood and in cabin and all fuses are good?
Please keep in mind the following NEW PARTS that have very recently (days/months) been installed before answering:
NEW PCM (though may be blown due to previous wiring damage unknown during its replacement)
NEW FUEL PUMP
NEW FUEL PRESSURE REGULATOR
NEW FUEL FILTER
NEW IGNITION COILS
NEW COOLING FAN DROPPING RESISTOR
NEW SPARK PLUGS
NEW PLUG WIRES (10k miles ago)
NEW DPFE Sensor (EGR)
GOOD ECT (tested)
Original TPS - not tested
Original ICM - not tested
have the same problem?
Sunday, May 31st, 2009 AT 8:24 PM