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Old 01-11-2015, 03:35 PM   #1
low82c10
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Re: 81 c30.....5.3

Quote:
Originally Posted by BP Automotive View Post
Sounds to me like you have lost power to the pcm, coils, or injectors. Most likely power to the pcm.

You can check PCM Connector Blue 19 for switched ignition power. Then Blue 20 and 57 for constant battery power.

Was the harness a new harness or a rewire?

Bill
Just checked pin 19 for switched that works as it should.

Check 20 and 57 for constant and that's there.
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Old 01-11-2015, 03:44 PM   #2
BP Automotive
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Re: 81 c30.....5.3

Now check the pink wire at the White color coil connector on each bank. Also check the pink wire on all of the injectors,

Then check the dark green/white wire in PCM Red connector Cavity 9 for the fuel pump relay signal. The PCM outputs a + signal on this wire.

You should use a Digital Multi Meter when testing circuits on a fuel injection harness. You could damage the PCM if you are not careful.


Bill
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Old 01-11-2015, 04:04 PM   #3
low82c10
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Re: 81 c30.....5.3

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Originally Posted by BP Automotive View Post
Now check the pink wire at the White color coil connector on each bank. Also check the pink wire on all of the injectors,

Then check the dark green/white wire in PCM Red connector Cavity 9 for the fuel pump relay signal. The PCM outputs a + signal on this wire.

You should use a Digital Multi Meter when testing circuits on a fuel injection harness. You could damage the PCM if you are not careful.


Bill
Checked both pink wires a coil connector both have 12V, on switched 12V should I be getting 12v at each injector?

I don't have a red connector to my PCM only a blue and green. I think green connector pin 9 is for the fuel pump correct?
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Old 01-11-2015, 04:16 PM   #4
BP Automotive
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Re: 81 c30.....5.3

I thought you were DBC. Yes, since you are DBW you will check the Green Connector. Each injector should have 12v at the pink wire.
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Old 01-11-2015, 04:17 PM   #5
low82c10
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Re: 81 c30.....5.3

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Originally Posted by BP Automotive View Post
I thought you were DBC. Yes, since you are DBW you will check the Green Connector. Each injector should have 12v at the pink wire.
Green connector on switched 12v has nothing, right as the turn the key the my meter jumps a few and goes to zero. And the pink wire on each injector does not have 12v on switched ign.
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Old 01-11-2015, 04:21 PM   #6
low82c10
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Re: 81 c30.....5.3

Quote:
Originally Posted by BP Automotive View Post
I thought you were DBC. Yes, since you are DBW you will check the Green Connector. Each injector should have 12v at the pink wire.
Sorry each injector does have 12v
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Old 01-11-2015, 04:55 PM   #7
BP Automotive
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Re: 81 c30.....5.3

Ok, now you will want to check for Ground at the PCM, and power and ground at the tac module connector.

On the PCM Connectors cavities 1 and 40 should have a good ground on BOTH connectors.

On the TAC Module Connector Cavity 7 should be Switched Ignition, and Cavity 15 should be Ground.

Also, Have someone crank the engine while you check for power at Green 9
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Old 01-11-2015, 07:10 PM   #8
low82c10
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Re: 81 c30.....5.3

Quote:
Originally Posted by BP Automotive View Post
Ok, now you will want to check for Ground at the PCM, and power and ground at the tac module connector.

On the PCM Connectors cavities 1 and 40 should have a good ground on BOTH connectors.

On the TAC Module Connector Cavity 7 should be Switched Ignition, and Cavity 15 should be Ground.

Also, Have someone crank the engine while you check for power at Green 9
PCM pin 1 and 40 show good ground with my test light.

TAC. Module 7 is good with switched 12V and 15 shows ground with test light.
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Old 01-11-2015, 07:12 PM   #9
low82c10
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Re: 81 c30.....5.3

Quote:
Originally Posted by BP Automotive View Post
Ok, now you will want to check for Ground at the PCM, and power and ground at the tac module connector.

On the PCM Connectors cavities 1 and 40 should have a good ground on BOTH connectors.

On the TAC Module Connector Cavity 7 should be Switched Ignition, and Cavity 15 should be Ground.

Also, Have someone crank the engine while you check for power at Green 9
Just noticed with the fuel relay disconnected I get 12V to pin 9 on PCM.
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