Help reading codes, 2.9L

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Sep 16, 2004 | 09:53 AM

RBWiseman

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Help reading codes, 2.9L

I'm working on an '86 Bronco II, 2.9L. I hooked up my analog VOM as the manual(s) described but can't seem to get any codes. When I first connect the VOM the needle immediately moves to ~ 12 V. When I turn the key to "on", I get one sweep from 12V to OV and back to 12V. I've triple checked everything. Barring a blatant hookup error, is there another possible explanation? A friend suggested that this could indicate a problem with the computer.

Thanks in advance.

Sep 16, 2004 | 01:53 PM

mrshorty

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From: UT

Assuming you have it hooked up right, it could indicate a problem with the computer. It could also indicate a problem with the wiring between the self-test connector and the computer.

Sep 16, 2004 | 02:01 PM

RBWiseman

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Thanks mrshorty. I'll double check to make sure that I'm on the correct pin (#4). Is the normal VOM operation for this check to sweep from 0V to 12V to indicate a pulse? If it is then I have a problem right out of the chute, because the VOM is already reading 12V before I even turn the key switch to on.

Sep 16, 2004 | 02:37 PM

mrshorty

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From: UT

It's been a while since I've read codes (been to busy being the father of newborn twins. don't have as much free time as I used to), so my memory may be a little rusty. As I recall, with the key off, you will read 12 V. Then the voltmeter will drop to 0 when you turn the key on and the self-test starts, then codes are output.

The behavior you are describing sound like normal "operating" behavior rather then "test mode". Do you have the STI terminal jumpered to STO in addition to having the voltmeter hooked up?

Sep 16, 2004 | 03:03 PM

RBWiseman

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Good question! I used two paper clips and an alligator clip lead to make the jumper, but am not sure I had continuity. I'll check that tonight.

We have one 6 month old starting to crawl around the house (grandson). I can't imagine how busy twins would keep you.

Thanks for the reply.