Fuel pump relay

[dohc281]

I've got a 98' Cobra and want to know where the fuel pump relay is. I think it is bad.

 

[Uncle Meat]

I've got a 98' Cobra and want to know where the fuel pump relay is. I think it is bad.

Look behind the drivers side tail light in the trunk. Should be mounted on the inside of that rear fender I believe. You'll have to pull the interior panel off to get at it.

U.M.

 

[BlownFiveLiter]

Welcome to :SNSign:

U.M., that would be the inertia switch. The fuel pump relay is a non-servicable unit inside the CCRM. Not sure where exactly it's located in the 96+ cars, but the CCRM is bolted to the fan shroud on the 94-95 models.

 

[Uncle Meat]

You sure? I could have sworn there was a fuel pump relay located back there too?

U.M.

 

[BlownFiveLiter]

Positive. Here's a wiring diagram, courtesy of Autozone, which shows the CCRM wiring for the 96-98 4.6L DOHC:

Edit: One of the other diagrams showed a fuel pump resistor, that appears it may be back there near the tank. I believe that was in one of the chassis wiring diagrams, not the engine controls.

 

[Uncle Meat]

Cool! Well now we know!

U.M.

 

[dohc281]

So are you saying I need to replace the CCRM?

 

[BlownFiveLiter]

I can't make that determination. I can honestly say that I don't know what makes the 4.6 cars tick, so I'm not sure what needs to be done in the way of diagnosis to determine if a component of the CCRM is bad. Hopefully U.M., or someone else can lend a hand in that department, or possibly move this to 4.6 Tech for a little more visibility, if you don't find the answers you need in here.

 

[COBRA90GT]

I've got a 98' Cobra and want to know where the fuel pump relay is. I think it is bad.

Why (symptoms? ) do you think your fuel pump relay is bad? What is your car doing (or not doing)? Have you ruled out other items first?


*edit*

BTW, read the response from "Joe D" in the following thread over on Corral. He typed out excellent troubleshooting techniques to determine if your CCRM may be faulty. Read them carefully and take a look at the contacts on your CCRM - remember, if one of the relays inside the CCRM box goes bad, you'll have to replace the entire box - $100 ballpark price, last time I checked.

http://forums.corral.net/forums/showthread.php?t=803483

 

[BlownFiveLiter]

Bad moderator, linking to a competitive site...

Tim,

As COBRA90GT said, "I *believe* that the CCRM (constant control relay module) is responsible for engaging the radiator fan when the A/C is activated, turning on the radiator low/high fan at a certain temperature, and has a relay for the fuel pump, among other things...

The CCRM is located in the passenger side (front) fenderwell. It is a little black box (4"x6") with a wiring harness connected to it."

The CCRM is a device that basically buffers EEC outputs and provides high current drive where necessary. Fuel pump, Fan, and AC Drive among others.

To answer your question, because the output side of the CCRM has such high current levels, a small amount of contact resistance translates to a large amount of heat generated at the output connectors. What can and has been seen with the fan circuits is the contact resistance generates enough heat that the connector housing can actually melt causing all sorts of intermittant circuit effects. If you have traced the weirdness in some circuits back to the CCRM, go the whole way to examinimg each connector pin and mating contacts for signs of heating and high contact resistance and you'll probably localize the problem. Make sure all the contacts in the specific circuit connectors are clean and tight. Look especially for subtle contact related things like a loose contact engagement or carbon streaks or partially melted housings that might make the contact pins move when the pins start getting hot. Good luck with it.

HTHs,

Joe

 

[dohc281]

Why (symptoms? ) do you think your fuel pump relay is bad? What is your car doing (or not doing)? Have you ruled out other items first?


*edit*

BTW, read the response from "Joe D" in the following thread over on Corral. He typed out excellent troubleshooting techniques to determine if your CCRM may be faulty. Read them carefully and take a look at the contacts on your CCRM - remember, if one of the relays inside the CCRM box goes bad, you'll have to replace the entire box - $100 ballpark price, last time I checked.

http://forums.corral.net/forums/showthread.php?t=803483

Periodically the car won't start. When this happens I do not hear the fuel pump ticking when I turn on the ignition. Sometimes it will almost start then then run like it is running out of gas. The main thing is that I can't hear the fuel pump running, 'when I do it will start and run fine.

 

[cobrachu]

Same problem here. I went to pull my 98 Cobra out of storage and when I turn the key I cant hear the fuel pump run. The fuse is good and in ten years this has never happened before. I did have the ccrm replaced last summer ($500) when my a/c was no longer fuctional. More problems maybe? Any way to jump the relay to rule out a bad pump?