crazy electrical problem with fuel pump. PLEASE read and help if you can.

[fastf50rd]

Alright to start, the car was running absolutely perfect before I parked her in the garage for the night. Next morning went to start it, fuel pump wasn't turning on. Checked all fuses and relays three times with a fine tooth comb, all fuses and relays are good. Next checked to see if there was power to the CCRM from the fuse box under the hood. All three constant hot wires have power. Next I checked the dark green/yellow wire coming from the CCRM to the fuel pump, no power. So, from that I gathered the CCRM was shot. Just for chits and giggles I plugged in a CCRM from an 87' ford taurus. To my disbelief the fuel pump kicked right on and is up to full pressure. Believe it or not the car actually ran somewhat normal with the taurus CCRM. Went to the ford dealership, got raped $150 bucks, plugged the new one in, NOTHING. NO pressure. Took it back, got a new one, still NOTHING. Plugged the taurus one back in, fuel pump turns right on. I've followed as many wires as I can see for chaffs or shorts, and I can't find anything. If any of you have any thoughts on how to find my problem, PLEASE let me know. I really don't wanna pay hundreds of dollars for a ford tech. to find the problem. Thanks for your help.
-Matt

 

[mustang479]

Alright to start, the car was running absolutely perfect before I parked her in the garage for the night. Next morning went to start it, fuel pump wasn't turning on. Checked all fuses and relays three times with a fine tooth comb, all fuses and relays are good. Next checked to see if there was power to the CCRM from the fuse box under the hood. All three constant hot wires have power. Next I checked the dark green/yellow wire coming from the CCRM to the fuel pump, no power. So, from that I gathered the CCRM was shot. Just for chits and giggles I plugged in a CCRM from an 87' ford taurus. To my disbelief the fuel pump kicked right on and is up to full pressure. Believe it or not the car actually ran somewhat normal with the taurus CCRM. Went to the ford dealership, got raped $150 bucks, plugged the new one in, NOTHING. NO pressure. Took it back, got a new one, still NOTHING. Plugged the taurus one back in, fuel pump turns right on. I've followed as many wires as I can see for chaffs or shorts, and I can't find anything. If any of you have any thoughts on how to find my problem, PLEASE let me know. I really don't wanna pay hundreds of dollars for a ford tech. to find the problem. Thanks for your help.
-Matt

Did you check the fuel pump reset in the trunk?

 

[fastf50rd]

oh yeah, one of the first things. The fuel pump works, it just won't work with my ccrm

 

[RIO5.0]

Sounds like your EEC has a learning disorder.... Check around for grounds and make sure everthing looks ok...happens when you pull the terminal so maybe somethings up with the cables??? weird but its a thought..
She's not learning so well anymore...?

 

[fastf50rd]

Alright, i've been through everything. Grounds, searching for shorted or chaffed wires, fuses again. I don't know what else to check. Anyone else have any thoughts? I really can't afford to get it towed to a Ford dealership and have them rape me.

 

[fastf50rd]

ttt

 

[mo_dingo]

Let me get this straight. By CCRM you mean the main computer, right??? I just wanted to be clear.

Which wire are you testing? Is it the 12V REF voltage? How many wires go to the fuel pump? Is it just a ground and a 12V source?

Simply put, the computer needs to know when to turn the fuel pump on. You need to verify that the computer is getting a 12V signal input on the ignition wire.

Start there. I don't know why a taurus computer works and brand new one won't.

Here is a link to some useful information.

http://forums.stangnet.com/showthread.php?t=533592
Scott