Dead CCRM??? Buzzing.

[95cbr331]

turned my ignition on to set my base fuel pressure w/o car started and the ccrm had this annoying buzz...
i do have fuel pressure..apparent because it leaked out an injector o ring.

story is the harness got in the way during the swap and slices a section of the harnes... i soldered and taped everything. thinking this may be a problem

or

could it because the box isnt mounted on anything quite yet.

or a coincidence taht it is bad>...

how would i test this???

 

[HISSIN50]

If a relay coil breaks loose, it could buzz (this is a common failure as far as CCRM issues go).

Not being mounted should not be an issue.

I'd want to find the source of the buzzing. This could be tough however. You'd almost have to pull fuses for given components (which have a relay housed in the CCRM).

Here's some info that might help.

Good luck.

 

[5.0_GT_kid]

I had something like this happen before. Turns out my turn signal relay went bad and was buzzing. Replaced it and everything was fine.

 

[95cbr331]

it is for sure coming from the ccrm. how do i test grounds?

 

[HISSIN50]

it is for sure coming from the ccrm. how do i test grounds?

Which grounds? You can see if they're in really bad shape if they ohm out poorly. Otherwise, I clean all of them and add additional ground pathways.

Good luck.

 

[95cbr331]

I was looking at the information you linked to and it said to probe grounds to the ccrm and such. thats what i was referring to.

 

[HISSIN50]

I was looking at the information you linked to and it said to probe grounds to the ccrm and such. thats what i was referring to.

I gotcha. Generally one checks the CCRM ground when a relay won't function (a relay needs to have its coil grounded in order to function).

If you want to check CCRM wiring, what I would check is:

that 13 has constant key-on power.

CCRM Pin 15 should have less than 5 ohms of resistance.

If the car still runs ok, you can almost forget even testing those (because if they were an issue, the EEC relay would be affected and your car would not idle).

If it's just a buzzing, again my best method is to get it to buzz and then disable each relay inside the CCRM, one at a time, till the noise stops. Doing this might be over the head of some less experienced mechanics. Alternatively, write down the CCRM part number on your CCRM and find another one on the internet. They generally go for 20-100 dollars. Getting a another CCRM would be the route I'd advise going.

 

[95cbr331]

thanks for the info hissin...

Ive made some progress on the discovery of where its coming from.
First- When i disconnect the square plug on the harness (that is near a round plug) downstream from the CCRM that then crosses over towards the driver side the buzzing stops.

2nd- heres a pic to help explain the next observation

I removed some of the maxi fuses from the under hood fuse box starting with the one labeled one then i also pulled the 2nd and 3rd, and thats when the buzzing stopped, ,at 3.

then i reinstalled 2, and left 3 out..no buzzing then i reinstalled 1 and there was buzzing.

so it seems the fuses 1 and 3 (my labeling) are causing the buzzing.

Hissin you have a next step for me? im trying to locate another CCRM.
any info on what these 2 fuses do?

THANKS AGAIN

 

[HISSIN50]

1 and 3 feed the ignition. The ignition (inside the car) feeds the coils of the relays. I bet if you put all your fuses back in and then went inside the car and pulled interior fuse 18, the buzzing would go away also. That would narrow it down to most likely being a bad relay coil in one of the relays.

A different CCRM sounds like a good plan to me. And since this feels like the issue, it's not worth narrowing down which relay coil is clicking because you still have to replace the CCRM (now if you have an electronics-nerd buddy, he can open the CCRM and probably fix the bad part. That's beyond most folks' abilities however. And it's still nice to have another CCRM, even if someone fixes your current one later on).

Ebay and the classifieds (if not here, then on the Corral) are two places where you can round them up pretty easily.

Good luck.

 

[95cbr331]

Out the door right now to go pick a ccrm up, 30 dollars and its out of a 94 gt that is being parted. Might Also be getting a black cobra hood. Craigslist is awesome

 

[HISSIN50]

Good deal.

 

[95cbr331]

picjed up the ecu harness and a different CCRM.

Tried the CCRM first didnt solve anything. then i installed the new ecu harness(mostly for curiosity) still nothing.

So then i started messing around... plugged the fan in and that kicked on. Then i disconnected the ABS connections and the fan wouldnt turn back on.

HELPPP..... pretty much the only thing keeping me from starting my car.

also my heater blower doesnt turn on when i turn the ignition on. what did i do?

for some reason i keep thinking grounds... all i have is a 10g from timing cover to core and then the 1/0 from the timing cover to the battery.

 

[HISSIN50]

Hey, the blower motor not working in and of itself is a sign of a bad ignition switch. Just something to remember.

The fan should not come on until you are at temp or have the AC on, unless the ECT is disconnected. The EEC actually actively turns the low speed fan off when it's not needed. Otherwise the default is for low to be on, as a system safeguard.

What's the part number on the CCRM you got? There are several part numbers that interchange.

Add yourself a motor to frame ground. Most of us use 4 AWG cable and run it from the passenger side motor mount (on the motor's side of the mount) to the passenger frame rail, near the ABS pump. For now, just put a jumper cable from the motor to frame. This is a quick and dirty way to make new ground pathways. In general, if your car will crank the starter, you have enough ground (the starter has about as large a draw as anything on the car).

 

[95cbr331]

would an ignition switch cause all this?

The ccrm is the same part number as the one i pulled off my car.

I dont have any of the AC plugged in and the ECT is plugged in (lower manifold on the heater tube)

i havent tried crankng the car yet. havent put any oil in.

im going to start pulling fuses and see if it gets rid of the noise.

 

[95cbr331]

i replaced the ignition switch because a buddy had one laying around. didnt do anything for the heater or ccrm...

I started pulling fuses. the ECU fuse makes it go away and so does the fuel pump fuse. so it goes away when i pull either 2 of the ignition, the ecu or fuel pump.

i pulled the ccrm back off and tested the harness pins... 13 had 12.15 volts and i tried testing the ground(pin 15) not sure if i hooked the multimeter up right.

i didnt get any voltage reading from 12 or 24, but i also didnt have the ccrm attached, is that a factor?

any other pins or tests?

from what i got with 12 or 24 im thinking bad ecu because the ccrm is fine.

but i cant test this theory because im pretty much the only 5.0 94-95 mustang around

 

[HISSIN50]

12 and 24 are only hot with the CCRM plugged in.

The EEC fuse affects CCRM pins 8, 10, 12 and 24.
The FP fuse only affects CCRM pin 11 (IIRC).

It sounds like your FP relay is chattering (the FP relay is non-functional if the ECU fuse is pulled). As such, CCRM pin 5 should show intermittant power when tested with an LED test light (while it clicks, the LED might be going on and off real quick).

 

[95cbr331]

ok, so...what could this mean? any thing i should check... i did replace the fuel pump during my build.

Aslo if it was the DB relay why would the fan kick on?

thank you hissin i appreciate it,

bad day so far... got hit by a car, slow, but it still hurt

 

[95cbr331]

Still not solved, and i have done some more investigation.

GOing off Hissin50's explanation of the Fuel pressure relay i started following the harness back towards the pump. Disconnected the Inertia switch and bam the buzzing stops...
so now if im correct i have narrowed down the circuit?
Not sure what to go off of at the moment but my assumption is the pumps wires r shorting out or are reversed? any other ideas.
The green wire leading to the inertia switch shows a constant voltage at the plug and when jumped to the other wire on the plug the noise continues.

getting there i believe.....

 

[HISSIN50]

I agree that you are getting close.

Is the buzzing coming from the CCRM or from the fuel tank?

 

[95cbr331]

Buzzing is coming from the CCRM.

I jumpered the fuel pump to the battery and i got a whir(good and working, loud though), so just experimenting i reversed the leads at the fuel pump harness...definetly wrong polarity at the pump.

So my new assumption is there is a problem in the wiring with the Green/light green fuel pump wire in between the ccrm and inertia switch. Tonights project is to splice into the wire by CCRM and run the power lead to the back and possibly a new ground....????
trying it with 10awg wire and a fuse

thanks again