2005 Escape Fuel Pump Control Module output?

[The_Eric]

I'm working on an Escape that stalls somewhat regularly after 3 hours of driving. The only code that I see is a P0191 (fuel rail pressure sensor). I suspect that the FPCM is dying and shutting off the pump which sets the pressure sensor code (I had a similar issue/code a few years back with my Lincoln Aviator and a bad FP relay). I hooked my lab scope up to the FPCM plug and it's getting Power and ground, a PWM signal to it, but it's out put only varies from about 5.5 to 6.5 VDC depending on RPM/load. The FP waveform looks really good and consistent and is drawing about 4.5 amps if I recall correctly.

Does anyone know what the voltage output from the FPCM should look like? I can't reproduce the stalling and don't want to toss parts at it.

 

[bdcardinal]

Remind me tomorrow and I can cruise through the WSM and see what I can see.

 

[clinebarger]

Did you check freeze fame data? Fuel Pressure PID high or low?

There is no voltage specification, The module runs the pump as slow as it can & still maintain fuel pressure.

Induce a high load situation by bypass some fuel out of the system with a pressure gauge....The FPM should react by running the pump faster to keep up with the higher volume demand.

The mechanical pressure gauge will also help sanity check the pressure sensor.


If you think it's heat related.....Try warming the FP module with a heat gun but don't go to crazy.

 

[Jetronic]

when it stalls, can you restart immediately, or are you stranded for a bit?

My attention would be going to the fuel pump, if it seizes for a second it might take full voltage to get it going again. Especially if it starts right after stalling. the electronics would still be hot.

 

[The_Eric]

Did you check freeze fame data? Fuel Pressure PID high or low?

There is no voltage specification, The module runs the pump as slow as it can & still maintain fuel pressure.

Induce a high load situation by bypass some fuel out of the system with a pressure gauge....The FPM should react by running the pump faster to keep up with the higher volume demand.

The mechanical pressure gauge will also help sanity check the pressure sensor.


If you think it's heat related.....Try warming the FP module with a heat gun but don't go to crazy.

That's a good idea, I'll bleed off some fuel and see how it responds.. I did run it for about an hour and a half, then hit it with the heat gun and tapped the FPCM housing and wiggled the connector but that didn't seem to make a difference.

 

[The_Eric]

when it stalls, can you restart immediately, or are you stranded for a bit?

My attention would be going to the fuel pump, if it seizes for a second it might take full voltage to get it going again. Especially if it starts right after stalling. the electronics would still be hot.

He says that it will always fire right back up.