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Where are my grounds?

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Old Jul 17, 2013 | 09:02 AM
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Default Where are my grounds?

My 90 vert has a slight chuggle at low speed. (which I suspect is an injector) My FSM says it might be a poor ground on the ECU causing it and I want to check it out before I buy the injectors. However, the FSM gives no clue about where my ground points are. Can you help me out?
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Old Jul 17, 2013 | 08:37 PM
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I have a 91 vert (same car) this diagram is from my section 8A electrical diagnosis service manual. It is a supplement to the FSM. HOPE IT HELPS.
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Old Jul 18, 2013 | 05:47 AM
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The picture didn't come through?
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Old Jul 18, 2013 | 07:25 AM
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I have 8A but couldn't find the ground points. I'm have a very hard time with this manual. It doesn't seem very user friendly to me. Can you give me a section or reference or even an exact page number?
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Old Jul 18, 2013 | 09:55 AM
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Default grounds

gm likes to put ecm grounds on the back of the heads. who knows why. i work at a gm dealer and still dont understand it...
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Old Jul 18, 2013 | 11:10 AM
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Great, that will help. Doesn't sound like a good place for a ground though does it? I was thinking on the frame.
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Old Jul 18, 2013 | 01:14 PM
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I would place a bet on the injectors they are known to be popo. Have you tried testing them?
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Old Jul 18, 2013 | 05:09 PM
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No but it's on my list. I've learned to check the free easy stuff first.
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Old Jul 18, 2013 | 05:11 PM
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Originally Posted by wedgeheaded
I have 8A but couldn't find the ground points. I'm have a very hard time with this manual. It doesn't seem very user friendly to me. Can you give me a section or reference or even an exact page number?
Page 8a-203-0
I hate photo bucket !
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Old Jul 18, 2013 | 06:40 PM
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Cool beans! I'll look it up tonight. Thanks!
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Old Jul 19, 2013 | 10:54 AM
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Thanks to everybody's help, I was able to sort my way through 8A of my FSM and found my ground spots. My ECM is grounded under my #7 spark plug via a small screw. I want to look this termination over and I'm hoping it's my problem. However, I still think it's my injectors. We'll see. Thanks again guys.
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