Computer Ground Wire Question

mkk50 · Sep 21, 2008

I recently purchased a new negative battery cable. Its from Motorcraft and comes with the computer ground wire quick connect attachment thingy. However, the other end that plugs into that on my car is just a crimp connector that whoever had it before me put on. Is there any place to get a replacement cable that starts where it should connect to the negative battery, and runs to the computer?

Thanks!

jrichker · Sep 21, 2008

The ground quick connect is often a victim of the efforts of previous owners. The simplest thing to do is just use a single screw for the battery to body ground. Then crimp or solder a 1/4" hole terminal onto the computer ground and connect it to the same place as the battery to body ground. Make sure that the ground connects to clean and shiny bare metal, and cover it with dielectric grease. The dielectric grease is available at the auto parts store in the same area as the silicone gasket sealer.

mkk50 · Sep 21, 2008

Thanks jricker, thats what is was planning on doing. Also, further up from where the quick connector should be on the harness side, it looks like three wires get crimped into one. Is this normal also?

Saleen0679 · Sep 21, 2008

That's normal. The single BK/LG wire is spliced with three other BK/LG wires.

Dsteen90 · Jan 26, 2010

im running into similar problems i bought a car for dirt cheap and it had the computer cut out. i replaced the computer and i hooked up the ecu and grounded it but im not geting fire to my fuel pump or pulse to my injectors. i replaced the pump and still nothing. i actually replaced the entire harness as well.

BlownFiveLiter · Jan 26, 2010

In the absence of injector pulsing and the pump not priming, chances are the PIP in the distributor is bad. You likely have no spark, as well? Is this a known running car, or one that's an ongoing project? It could be more, but the bad distributor is the usual culprit with the symptoms you're experiencing.

HISSIN50 · Jan 26, 2010

Depending upon how "no fire" is interpreted, I'd add that the pump should prime even if the dizzy is removed.

Dsteen90 · Jan 26, 2010

well what should i do? should i buy new parts for my dist. or break down and buy a new ecu? or what!!!

HISSIN50 · Jan 26, 2010

Do some diagnostics. Ground the fuel pump test connection and note the values at the FP relay.

Use a test light to check for constant key-on 12V to your injectors.
Check for spark.
If you have spark but no inj pulse, ensure the TPS is not shorted to VREF.

Jrichker has a Cranks but No-Start checklist that will help you immensely. It's in the Useful Tech Sticky.

Good luck.

Dsteen90 · Jan 26, 2010

I Have constant to my injectors just no pulse.
I have power to all wires on my FP relay except one i think
i just changed out the relay so theres no possible way its bad.
ill run through that check list but i doubt it will help i read over it

and im not trying to sound dumb, but im not sure on how to check the TPS shortage thing. sorry im an old school chevy major im just getting into the realm of fords.

liljoe07 · Jan 26, 2010

See if you have 5v at the TPS orange wire.

You did hook all the ECM ground points up? There are two of them.

HISSIN50 · Jan 26, 2010

And for the pump, if you have output at your FP relay, check for power and ground at the FP connector at the tank.

liljoe07 · Jan 26, 2010

HISSIN50 said:
And for the pump, if you have output at your FP relay, check for power and ground at the FP connector at the tank.

Im thinking the ECM isnt powering. I know Ive use it before, asking if the injectors have 12v. But given the way the circuits work, You can have 12v at the injectors, but the ECM wont power up if something is internally wrong, OR, the grounds are not hooked up. Thus I doubt he will get a Fuel Pump prime. Thats IF, my thinking is correct. Thats why I like to see if the Reference Voltage is there at one of the sensors.

Dsteen90 · Jan 26, 2010

Alright i jumped the fuel pump from the test connector and it turns on.

I have power to Two out of four wires for the relay before i jumped it with key on.

Red- Power
pink/Grey stripe- Power
Green/light green stripe- No power
blue with orange stripe- no power

I again plugged up to one of the injectors and turned it over with no results.

alright i even went as far as testing some of the wires out of the dist. only two had power

peach/yellow power
red/green power
Gry/Orange nothing
red/blue nothing
tan- Nothing
peach/red- Nothing

The intertia switch has no power on either side.

And i know for an absolute fact the grounds are proper, but i even went as far as double checking them.

NOW! what sensor do you need me to test, and if you will please disclose the location of the sensor and how to test it

liljoe07 · Jan 26, 2010

TPS sensor on top of the throttle body. It has 3 wires. Orange, Green, and Black. Test the orange to the black wire. Should be 5v or so with the key on. Do this first

The power to the TFI is fine.

Dsteen90 · Jan 26, 2010

its reading 1.14

liljoe07 · Jan 26, 2010

Not looking good for the ECM.

Go to the ECM. Find PIN 1. Its the only pin with voltage with the key off. See what that reads. Should be battery voltage.

HISSIN50 · Jan 26, 2010

Dsteen90 said:
its reading 1.14

Might check all 3 wires just in case the wiring is tough to decipher. Your reading would be good for a TPS output (you want to check the input).

Dsteen90 · Jan 27, 2010

Alright tell me this. The computer was stolen therefore i didnt know what computer code to get when i bout it. I knew i needed an A9L and someone told me it didnt matter which it was it would work regardless

SO im calling around for a knew computer and this guy tells me that if its the wrong computer that it will not work due to some controllers or something of the such!

SO if you all could possibly shed a little insight that would be WONDERFUL!

liljoe07 · Jan 28, 2010

5 speed car= A9L
Auto = A9P

Although you can use either ECM

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