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The Parts Guy
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7,304 Posts
Discussion Starter #1
Here's the problem:

I've finally finshed the 4.6L DOHC swap into my 90 XR7. I'm using a 97 4.6L Tbird EEC, dash, dash wiring harness, EEC harness, engine compartment harness, and engine harness.

I was going to start the car for the first time tonight, but I ran into a bit of a problem. Here are the things that are wrong:

1) The fuel pump does not turn on when the key is turned to "ON"

2) The fuel gauge climbs to "FULL" when the key is turned to "ON" even though there is only 4 gals of fuel in the tank.

3) The fan begins to run as soon as the key is turned to "ON"

The fuel pump cutoff switch is depressed. I'm pretty sure that I have this narrowed down to the CCRM (black box in front of air filter box). I am using the 97 4.6L CCRM, which worked fine in my donor car (the car ran), even though it has a good sized dent in it. I'm almost 100% certain that the CCRM controls both the fan and the fuel pump.

Here are my questions:

1) Could it be anything other than the CCRM causing these problems?

2) Could the CCRM just be receiving a bad ground?

Thanks for any assistance.

-Rod
 

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Whining Intakes Rock
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3,645 Posts
CCRM has the fuel pump relay and does control the fan. The PCM signals the fuel pump relay to go on for 1 second when you turn key on, and then again when you crank. Sounds like it could be a bad ground. Here is the schematic:



Link to larger version
 

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The Parts Guy
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7,304 Posts
Discussion Starter #3
I'll check the CCRM ground tomorrow morning and let everyone know if that was the problem.

Man, it would be great if that was the only thing keeping me from starting the car. *Crosses fingers*

-Rod
 

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The Parts Guy
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7,304 Posts
Discussion Starter #4
Well, I cleaned up the ground for the CCRM and nothing changed. I then swapped CCRM's with a spare one that I had on the shelf, and nothing changed.

The fuel gauge still goes wherever it pleases. Sometimes when you turn the key to "ON" it will move up to "FULL", other times it will move to almost "EMPTY", which is where it should be.

The fuel pump still isn't running when the key is turned to "ON"

The fan still kicks on as soon as the key is turned to "ON"


Anyone have any ideas?

-Rod
 

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Whining Intakes Rock
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3,645 Posts
Check the harness on the EEC? Maybe try swapping another EEC is you have one just to rule that out.
 

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The Parts Guy
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7,304 Posts
Discussion Starter #6
The harness is secure on the EEC. I don't have another one to try, as this is the only one that I have that has been flashed to work with this combination.

I'm going to get out the multimeter and see if I'm getting power at the fuel pump relay when the key is turned to "ON".

I'll be back with the results shortly.

-Rod
 

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The Parts Guy
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7,304 Posts
Discussion Starter #7
Ok, the fuel pump inertia switch is not receiving power when the key is turned "ON", therefore it isn't supplying the fuel pump relay with power.

I double checked the connection at the EEC, it is secure.

For some reason, the CCRM isn't sending power to the inertia switch, so power can't make it's way to the pump relay and then to the pump itself.

Any ideas?

-Rod
 

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The Parts Guy
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7,304 Posts
Discussion Starter #9
I think I have the problem figured out. Hopefully I'll have it running some time tonight. I'll let everyone know what happens.

-Rod
 

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The Parts Guy
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7,304 Posts
Discussion Starter #10 (Edited)
Scratch that, I haven't figured it out yet. I just replaced the entire wiring harness from the dash to the taillights with the harness from the 97 donor car, so now all of the wiring in the car is from the donor car. SAME PROBLEMS.

I'm looking over some schematics right now, and I'll start hunting down the problem tomorrow morning. I'm just a little too frustrated to keep working tonight. I was supposed to go on a vacation tomorrow, but I won't leave until I hear this thing fire up.

EDIT, additional info:

I'm wondering if the EEC could be causing the problem. Is that a possibility? I'm going to check the pins coming from the EEC (#40 and #80, PK/BK and LB/O, respectively) that power the fuel pump relay in the CCRM tomorrow morning. If the EEC isn't sending a signal through at least one of those pins when the key is turned to "ON", I'm assuming that the problem lies within the EEC.

I also plan to check pin #11 (BK/Y) at the CCRM, to make sure it is receiving 12V power at all times.


-Rod
 

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The Parts Guy
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7,304 Posts
Discussion Starter #11
I've double checked all of the wiring involving the fuel pump and fan. Here's what I've come up with:

Pin #11 @ CCRM (BK/Y) - has 12V power at all times, like it should

Pin #80 @ EEC (LB/O) - has 12V power when the key is "ON". This is the fuel pump relay output from the EEC, so I assume that it is operating correctly.

Pin #40 @ EEC (PK/BK) - has no power at any time. This is the fuel pump monitor wire, going to the EEC. Since the fuel pump doesn't run when the key is "ON", it makes since that it does not have power in this wire.

I've tried two CCRM's now, both of which I believe are good. I'm kind of wondering about the EEC, but since it is sending power to the fuel pump relay in the CCRM with the key "ON", it seems to point towards the CCRM as being at fault.

Anyone have any ideas?

Remember, for all purposes, this is a 97 4.6L LX with a 4.6L DOHC. There is not one piece of original 90 XR7 wiring in this car, it has ALL been converted over to 97 4.6L wiring.

Thanks for any help.

-Rod
 

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It is nice
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885 Posts
make sure that power is going to the pump itself at pin #5 of ccrm after the relay - also check that the fuel pump cutoff switch isnt preventing the pump from starting you should have power after the shutoff switch if you do then check the pump itself could be bad ground at the pump.
 

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It is nice
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885 Posts
also im not positive but pin #40 of eec should have power suggesting you have no power after the fuel pump relay circuit may be open there. check pin #18 of ccrm with ignition on also
 

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The Parts Guy
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7,304 Posts
Discussion Starter #14
Pin #5 at the CCRM (PK/BK) does not have power at anytime, even though the EEC is sending power from EEC pin #80 (LB/O) to the fuel pump relay at the CCRM.

Pin #40 @ the EEC should be receiving power (it's the fuel pump monitor/power wire) but it isn't receiving power either.


Eventually I grew tired of all of this, and used a jumper wire to direct wire the fuel pump to see if that would at least run the pump. That worked, although the fan still ran with the key "ON", and the fuel gauge wasn't correct. We tried to fire it up, and found that the fuel injectors are not firing when the engine is cranking. I checked the fuel injector wires at the EEC (I don't remember the pin #'s, I left my notes in the shop) and the EEC isn't sending signals to the fuel injectors to fire. Also, the check engine light does not even come on when the key is initially turned to "ON", even though the bulb is not burned out (I double checked the bulb). All of this really points to the EEC being bad.

Let me know if you guys think otherwise.

If it comes down to it, I don't mind wiring in my own relay and switch for the fuel pump, but I need the injectors to fire, and the fan needs to operate correctly.

Thanks,
Rod
 

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The Parts Guy
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7,304 Posts
Discussion Starter #15
Also, it has been brought up that the pins may be crossed up, either at the EEC or at the CCRM. All of the wiring was simply removed from the running donor car and installed on this car. The EEC and CCRM are also from the donor car. The only wiring modifications that had to be performed were the lengthening of a few wires on the engine harness to fit the DOHC engine. All wiring modifications were done correctly, by soldering the wires together and heatshrinking them. I'm pretty certain that the EEC must have been damaged somehow in handling when it was shipped out to be flashed. Static electricity, magnets, x-rays, etc probably aren't too friendly to EEC's.

-Rod
 

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It is nice
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885 Posts
this may be far fetched im not sure about it but is the ignition switch the same in the 90 as 97 "pin wise" that could be your problem, or else you may be right that its the eec if even check engline light dont come on.
 

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The Parts Guy
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7,304 Posts
Discussion Starter #17
I'm using the 97 ignition switch, so that wouldn't matter. Basically this car is a 90 Cougar XR7 body, 97 Tbird LX interior and wiring, and 94 Lincoln Mark 8 drivetrain.

-Rod
 

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The Parts Guy
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7,304 Posts
Discussion Starter #18
Update:

Finally got a hold of another EEC. I installed it, and the car still has the same problems. I don't have any more time to work on the car this weekend, but next weekend I plan to verify that the pins that should be supplying power to the EEC with the key "ON" are actually supplying power to the EEC. It seems like the EEC isn't getting power.

-Rod
 

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It is nice
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885 Posts
lol...yea its gotta be the wiring keep us posted
 
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