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astro2k
New User
May 30, 2008, 2:39 PM
Post #1 of 5
(4073 views)
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Car - 1988 Oldsmobile Regency 3800 V6
The car was running rich, so I did the pressure test and found that an injector was leaking...I found the leaking injector, and tested the circuit with a noid light. The light was constantly on (even during cranking), indicating a short.. I measured the resistance on the ground side from the ECM to the injector and the wire is good... There are no fault codes, and the ECM flashes code 12. So, now I'm thinking bad ECM. Any other ideas? Thanks!
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Guest
Anonymous Poster
May 31, 2008, 12:49 AM
Post #2 of 5
(4058 views)
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u sound like you know what your doing, but i think one bad injector would fault the ecm out. salvage yard can sell you an injector for about 10 bucks. try testing your tps. had fun fixing a similar problem. good luck
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DanD
Veteran
/ Moderator
May 31, 2008, 3:39 AM
Post #3 of 5
(4057 views)
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I think you’re probably right that the driver (grounding switch) in the computer is likely shorted (fused) to ground.
Did you make sure that this path to ground goes away when you disconnect the computer?
Also check the resistance value of the affected injector.
An injector with shorted windings with have vary low resistance; causing high current flow, which may have taken out the driver.
Even if you just compare it with another known good injector’s value; they all should be fairly close to each other.
Dan.
Canadian "EH"
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astro2k
New User
May 31, 2008, 12:23 PM
Post #4 of 5
(4052 views)
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Yeah, theres no short when the ECM is disconnected.. Also tried swapping injectors - still leaks.
Do they really say EH in Canada? :)
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DanD
Veteran
/ Moderator
Jun 2, 2008, 10:58 AM
Post #5 of 5
(4041 views)
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By switching the injectors around is a good way to make sure that the problem isn’t just a stuck or leaking injector.
My concern is what happened to the computer; why did it take this circuit to ground and hold it there?
That’s why; I suggested checking resistance value of the injector(s).
If the resistance is to low, it could damage the replacement computer. The injector will work but over time, the excessive current flow, could burn or short the diver again.
Excessive current flow is another reason why we use a noid light or a self-powered test light to check injector pulse. A regular test light can take out a driver on its first pulse.
Dan.
No I/we don’t use EH a whole lot, EH but I guess we’re known for it EH. LOL
Canadian "EH"
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