TweakFreak

Hi Folks,

I just recently purchased a Procharged Mach 1 and I'm having a bit of trouble .

The car began to cut out when hitting bumps. Sometimes from a cold start it would fire up no problem... sometimes it wouldn't and you just wait for a bit and it'd then fire up.

I went ahead, dropped the tank and changed the fuel pump(old/new were Aeromotive 340LPH). After doing this the car starts every time, but only runs for about 5 seconds and cuts out. It starts fine, idles at about 1000RPM then sputters out.

The computer now reports P0190 "Fuel Rail Pressure Sensor Circuit Malfunction". After doing some reading I find that folks like to replace the FRPS(Fuel Rail Pressure Sensor) when seeing this code. Seems that the diaphragm has a tendency to blow out under boost applications. I ran to the local auto parts store and picked one up. I popped that into the fuel rail and experienced the same behavior.

I went ahead and changed the fuel filter as that's cheap and easy... no change in behavior.

A friend had an extra FPDM (Fuel Pump Driver Module) so I swapped that, no change in behavior.

I inspected the inertia switch and observed that it had not activated. I figure the car wouldn't start at all if the switch was activated.

I inspected the fuse panel under the hood, all looks good there.

I've seen some talk about replacing the o2 sensors, but I'm a bit hesitate to keep throwing parts at it with taking a more educated approach.

I'm sort of at a loss. Does anyone have suggestions?

TweakFreak

Just an update. I checked Vref at the FRPS connector. It's a steady 5.02v at Key On Engine Off state. I used instructions found in this thread: here

I'm still fairly stumped. I'm reviewing some electrical diagrams of the car to see if there's other things I can check.

JC316

Almost sounds like the PATS system is getting pissy. That p0190 code was coming up for me when I was unplugging the fuel pump on an 03 taurus and running the gas out. Check the fuel pressure at the rail.

Also check the fuel pump relay, i've had them get weak over time and give intermittent power.

TweakFreak

Thanks for the suggestions.

I considered PATS. I have two keys and tried both thinking that maybe one of the key's weren't doing so well. Seems like it wouldn't fire at all if PATS wasn't operating properly. I don't recall every seeing the theft light flash.

I believe the relay is located in the CCRM. I don't have an extra one of those around to try. I'm stopping over at the local auto parts store to rent a fuel pressure gauge. I'm curious to see exactly what's going on at the schrader valve. I'm thinking some pressure at prime, but tapering off once idle.

TweakFreak

Found the problem. Looks like Aeromotive switched the polarity on the new revisions of the 11142 model! The pump was going backwards the whole time!



Flipped the pins in the connector and fired up! Hope this helps someone.

VTX1800N1

Wow!

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