Dead CCRM??? Buzzing.

[95cbr331]

still no success
the green/ light green fuel pump wire splits into 2 soon after the ccrm... one goes back to the inertia switch then to the ecu...
what is the purpose of the wire going to the ecu? if the ecu is bypassed so no green wire the noise is still present.
what are the other circuits involved with the FP relay?

thanks,
the highly confused and frustrated Brandon

 

[HISSIN50]

The other part of the circuit is the Fuel pump monitor. It's kinda like what the IDM is to the ignition [but for the fuel pump].

I don't understand about the polarity. Were the wires for the FP reversed during the pump install?

 

[95cbr331]

when i mentioned polarity..yeah thats what i meant, that possibly the wires were reversed.
Do you have a wiring diagram for the fuel pump circuit?
also since i bypassed the ecu and it still did it, it rules out the ecu being bad?

 

[HISSIN50]

It does suggest the ECU is fine.

If you disconnected the electrical connector for the fuel pump (above the tank) and the noise went away, that would suggest it is an issue at the pump. I dont know why the CCRM itself would make noise however. Maybe there's an inductance issue with the pump wired backwards or something (though I can't think of how).

I dont have a postable online resource for the fuel system diagrams. For the FP, you should find that a 20 amp fuse feeds a yellow wire to CCRM Pin 11. A DG/Y wire at CCRM Pin 5 egresses the CCRM and branches off. One leg goes to the EEC as you noted and the other goes to the inertia switch, where the output changes to Br/Pink. The FP itself has a blk grd wire.

 

[95cbr331]

nothing is working...i mean as in fixing this.
im getting a new ecu to try but its gonna be a week before i can get to try it.

this is the last thing to try....done everything else that seems possible. tested old fuel pump, ran new power wire to inertia switch direct ground at the pump.

hissin we both agreed it didnt sound like a ecu problem, but im thinking its something to do with the ground pulse or the circuit with the red green wire. thinking something might have shorted it since it is possible the circuit was energized when the harness got sliced...damn rear mounted batteries and to many damn lil projects , honestly cant remember if it was or not.

if i was to directly ground the ccrm, which wire would i splice into... pin 15? or others?

 

[HISSIN50]

nothing is working...i mean as in fixing this.
im getting a new ecu to try but its gonna be a week before i can get to try it.

this is the last thing to try....done everything else that seems possible. tested old fuel pump, ran new power wire to inertia switch direct ground at the pump.

hissin we both agreed it didnt sound like a ecu problem, but im thinking its something to do with the ground pulse or the circuit with the red green wire. thinking something might have shorted it since it is possible the circuit was energized when the harness got sliced...damn rear mounted batteries and to many damn lil projects , honestly cant remember if it was or not.

if i was to directly ground the ccrm, which wire would i splice into... pin 15? or others?

You got it with the CCRM ground. It's CCRM Pin 15. Note that this is the general ground for the relay coils in the CCRM. If none of the EEC systems woke up with the key on, this is the wire to check.

The fuel pump relay's ground is modulated via the EEC. This is done at CCRM Pin 18. If your pump would not prime, this would be the wire to check.


If you're talking about the Red/Lt green wire (CCRM Pin 13), you can check this with your test light. Remember, that wire has nothing to do with the EEC. It gets power via the ignition switch. You should be able to jump FUSED battery power to this wire to see if that helps.

This thread has gotten pretty long and a bit tough to follow. If everything seems mostly copacetic sans the noise and possible fuel pump performance issues, it seems like a wiring issue at the fuel pump, no? If your DG/Y wire (at the inertia switch for example) has 12 volts like it should, any reversal of polarity would be in the tank connections it seems. I would not reverse the polarity of wires in the body harness because you can now send a ground signal to a circuit in the EEC which monitors voltage. If there's doubts with the pump's wiring (in the tank), I'd fix that directly.

I'm probably way off base (especially since it's super late)................
Good luck.

 

[95cbr331]

This thread has gotten pretty long and a bit tough to follow. If everything seems mostly copacetic sans the noise and possible fuel pump performance issues, it seems like a wiring issue at the fuel pump, no? If your DG/Y wire (at the inertia switch for example) has 12 volts like it should, any reversal of polarity would be in the tank connections it seems. I would not reverse the polarity of wires in the body harness because you can now send a ground signal to a circuit in the EEC which monitors voltage. If there's doubts with the pump's wiring (in the tank), I'd fix that directly.

i have voltage at the inertia switch which makes me think different, also i took my old stock pump(out of the car) and jumpered it(with correct polarity) to the factory harness...with same results, nothing.

If you're talking about the Red/Lt green wire (CCRM Pin 13), you can check this with your test light. Remember, that wire has nothing to do with the EEC. It gets power via the ignition switch. You should be able to jump FUSED battery power to this wire to see if that helps.

this is the same wire as the lead to the coil... i tore through the other harness i had and i believed i followed it to the ecu. but i could be wrong.

going to jumper ccrm pins 15 and 18 to known grounds and see if that atleast gets rid of it, and check voltage at the inertia again.

I appreciate your help Hissin50. i'd buy you a beer if we lived near each other and if i could actually buy beer, ha. Need any parts? i have lots of extras..some interior, motor,ect..

 

[95cbr331]

still haven't gotten an ecu to test the computer.
my latest finding is if i ground the blue/ red wires at the the diagnostic plug all my problems go away.
thinking about just grounding these...?

 

[HISSIN50]

still haven't gotten an ecu to test the computer.
my latest finding is if i ground the blue/ red wires at the the diagnostic plug all my problems go away.
thinking about just grounding these...?

I don't have diagrams in front of me right now. What are the exact colors of the wires (including traces) and what do they go to?

 

[95cbr331]

i meant the blue wire with orange tracer that comes from ccrm18. it goes from the ccrm to the diagnostic plug then from the same pin in the diagnostic plug to the ecu.

when i ground it at the diagnostic plug its all good...

 

[HISSIN50]

i meant the blue wire with orange tracer that comes from ccrm18. it goes from the ccrm to the diagnostic plug then from the same pin in the diagnostic plug to the ecu.

when i ground it at the diagnostic plug its all good...

That makes more sense. If grounding this wire manually makes the chatter go away, I'd check resistance in the wire during the prime-out (do this test without having the wire manuallygrounded. In other words, have the wiring the way it is from the factory).

If your FP ground strap (in the EEC) is starting to go south, I suppose you could see chattering with the relay coil. Manually grounding the circuit would remove this chatter.