CCRM...

[xman1999]

Hi,

I'm tracking down an issue I'm having with my 95 mustang....I belive that its the CCRM but am open to suggestions.

I'm not getting the initial startup/sound from the fuel pump with I turn on the ignition nor am I seeing any fuel pressure (Phantom gauges). I know I'm getting power to the pump since I bypassed the relay (Procharger P1sc system) and made sure the the inertia relay works as well. I've checked all the fuses, connections, etc.

I then removed the CCRM connection and followed some suggestions I've herd on this board as well as from here:

http://www.mustang-tech.org/wiki/94-95_Mustangs_Electrical_CCRM

Here is what i followed:

I checked the power/pins going into the CCRM....is there another way?

1. Check the inertia switch in the trunk and the fuel pump fuse in the underhood fuse box (20 amps). Also check the ignition switch fuses. With the key turned to run and checking within the fuel pump prime-out period (a duration of 2-5 seconds after turning the key to run) Checked - everything seems OK

2. Check CCRM pin 5 for accessory 12 volts. Checked - No reading from my meter, also when I accedently made contact with Pin 4, the pump started and I had fuel Pressuer

If you have it, the issue lies downstream. If not: Check CCRM Pin 11 for constant 12 volts. Checked - have 12 volts

Check CCRM Pin 13 for accessory 12 volts. Checked - have 12 volts

Check CCRM Pin 18 for a ground signal during the prime-out
How do I check this?

If this is all good, check the inertia switch (located in the driver side trunk, adjacent the tail light) and fuel pump electrical connector at the tank.

I also followed some the EEC troubleshooting and am finding that pins 12,24 only are getting about 3v max....this seems to suggest the EEC relay is bad inside.

Any suggestions on where/what to check.

Robert

 

[95cbr331]

may be your computer.... i just traced down an issue with my ccrm where i had no prime out period and my fuel relay would chatter(in the ccrm).

check all your grounds first, try another ccrm.

you can also try grounding the red/blue wire on the diagnostic port and if the fuel pump turns on i'd say its your ecu that is bad. this being because once this wire is grounded you bypass what signals the fuel pump relay from the ecu.

 

[HISSIN50]

To check Pin 18, connect your DMM to this terminal. Connect the other end to a solid ground. Set your meter to read ohms (the lowest scale is fine).

The above advice to ground the FP terminal on the self test connector is a good one. This wire is the same as the one you're testing - you will be manually grounding the same wire.

There's a chance the the ground strap for this terminal burned in the EEC. But because of your notation of CCRM pins 12/24, I dont think this is the issue. See below.

From your testing:

2: you bridged battery power to your pump (jumping 4 and 5). So you know the wiring from the CCRM to the pump and the pump is good. Cool.

Pin 11 having power means the FP fuse and wiring from the battery to the CCRM is good (common terminal on your relay).

12 and 24 are an issue. When you turn the key on, use your DMM to see if you have VPWR. A quick way to check this is to see if your coil has 12 volts on the + terminal. If you really are seeing 3 volts at 12/24, your reading will suck.

If this is the case, run the diagnostic pathway I wrote about for the EEC relay (same Wiki page as the FP stuff).


Have you moved any grounds around lately? I'm wondering if something like the EEC ground was moved or went partially bad.

 

[xman1999]

Thanks for the help...

Thanks again for your replys....The way I'm testing the pins is by disconnecting the harness from the CCRM and checking the Pins on the wiring harness....Is this the way to do it? Also, I am getting 12v going into the Distributor.

Robert

 

[HISSIN50]

Robert, this method doesn't work. You'll never have any power at the Normally Open terminals of the relays (the terminal that has power leaving the CCRM and going to the device). It would be like disconnecting your headlight switch and then testing for power leaving the switch and going to the lights. It's obviously not going to happen.

Since that method works for the other terminals (the other 3 are input terminals), just retest the outputs. So check Pin 5 again (power to the pump), and check 12/24 again.

When you got 12 volts going to the dizzy (I'm not sure exactly what you checked, or if you tested the coil) but if that was with the CCRM plugged in, that makes sense.

 

[xman1999]

Thanks Hissin50

I agree that the way I was testing was more about the power going into the CCRM not necessarily coming out....other than opening the CCRM up, how would you go about testing Pin 5, 12, 24? As for testing power to the coil, I disconnected the lead going into it and measured from the pins.

Also, If I dont' get power comming out of #5...i guess the writings on the wall that I'll need a new CCRM.

Pins 12, 24 are incomming correct? I should be getting 12V but I really think that I'm only getting 3-4V incomming....wierd. From the diagram, 12,24 are supplying power to the CCRM correct?


Robert

 

[HISSIN50]

I agree that the way I was testing was more about the power going into the CCRM not necessarily coming out....other than opening the CCRM up, how would you go about testing Pin 5, 12, 24?

With the CCRM connected, you have to be creative. You can use a safety pin, etc to get into the wire. Then connect your meter lead to the safety pin (be sure you dont let the safety pin touch metal).

As for testing power to the coil, I disconnected the lead going into it and measured from the pins.

That works ok since you were testing power into the coil.

Also, If I dont' get power comming out of #5...i guess the writings on the wall that I'll need a new CCRM.

It can also be a wiring issue. But if you have 13, 18 and 11 doing what they should be, then one could assume the FP relay in the CCRM is bad. If you haven't, be sure to try the grounding of the self-test FP terminal. The most likely fault is the ground input into the FP relay's coil.

Pins 12, 24 are incomming correct? I should be getting 12V but I really think that I'm only getting 3-4V incomming....wierd. From the diagram, 12,24 are supplying power to the CCRM correct?

They're output to the EEC. 10 is the load-side incoming power for the EEC.

 

[xman1999]

Hi guys,

I took a little break from working on this problem and even bought a new CCRM. After charging the battery/jump I still don't hear the fuel pump kick on. When I ground the FP terminal on the self test connector the fuel pump kicks on. All fueses seem fine...could it be the computer? Is there a way to "Reset" it?

Rob

 

[95cbr331]

i would take that as a sign the ecu has gone south... try to find someone with a 94/95 who will let you try their comp and see if that will resolve the issues.

good luck

 

[xman1999]

Appreciate the help/responses

thanks guys,

I'll see what I can do....

Robert

 

[HISSIN50]

There's a ground strap inside the EEC that can let go, causing a lack of commanded continuity to ground when the FP relay needs to energize. Some guys just work around this (permanently grounding this wire).

Your DMM should tell the story - check continuity-to-ground in this wire during the prime-out.