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> '72 fuel injection problem driving me insane!
buck toenges
post Jun 18 2007, 05:38 PM
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Here is the deal. My passenger side cylinders aren't firing. The injectors are tested fine, the timing and compression are fine. I have the grey booted f.i. injection harness toward the front of car and the black boots on the rear injectors. If I take off the injector harness on driver side cylinders then you can tell that the engine stumbles. If I take them off the passenger side I don't notice engine stumble. The passenger side exhaust pipes do warm up some as you let engine idle but not hot like driver side h.e.

Where do I go from here? I will trade the passenger side injectors to the driver side to make sure they work but then what?
I did replace the injector harness, brain, and passenger side injectors out but that didn't change anything.
I am getting 12 volts out at injector harness.
Should I check the grounds? Could the grounds for the passenger side not be grounded properly?
Is there a proper way for the f.i. harness to be connected to the injectors? I can turn the harness 180 degrees to the injector. Sort of like placing the connector upside down and still connect into the injector. Does this affect the injector in doing its job?

I am sort of lost here.
Thanks,
Buck
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TravisNeff
post Jun 18 2007, 05:41 PM
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Check your injection trigger points.
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Cap'n Krusty
post Jun 18 2007, 06:07 PM
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QUOTE(Travis Neff @ Jun 18 2007, 04:41 PM) *

Check your injection trigger points.


Why? He said the other side works fine. Check the grounds under the intake manifold. There are several there, and they can loosen. They're on a case through bolt near the flywheel end of the top of the case. The Cap'n
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TravisNeff
post Jun 18 2007, 06:27 PM
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(IMG:style_emoticons/default/huh.gif) Doh! You caught me on that one.
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dr914@autoatlanta.com
post Jun 18 2007, 06:42 PM
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QUOTE(buck toenges @ Jun 18 2007, 04:38 PM) *

Here is the deal. My passenger side cylinders aren't firing. The injectors are tested fine, the timing and compression are fine. I have the grey booted f.i. injection harness toward the front of car and the black boots on the rear injectors. If I take off the injector harness on driver side cylinders then you can tell that the engine stumbles. If I take them off the passenger side I don't notice engine stumble. The passenger side exhaust pipes do warm up some as you let engine idle but not hot like driver side h.e.

Where do I go from here? I will trade the passenger side injectors to the driver side to make sure they work but then what?
I did replace the injector harness, brain, and passenger side injectors out but that didn't change anything.
I am getting 12 volts out at injector harness.
Should I check the grounds? Could the grounds for the passenger side not be grounded properly?
Is there a proper way for the f.i. harness to be connected to the injectors? I can turn the harness 180 degrees to the injector. Sort of like placing the connector upside down and still connect into the injector. Does this affect the injector in doing its job?

you may want to check the injector ground leads at the back top of the engine case and then check for an intake leak at the runner to head connection. (we have also had problems with rebuilt injectors firing outside of the car but not when installed!

I am sort of lost here.
Thanks,
Buck
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buck toenges
post Jun 19 2007, 09:14 AM
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I am reading 12 volts at the injectors. Would this eliminate the ground issue?
Thanks,
Buck
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Chris Pincetich
post Jun 19 2007, 11:49 AM
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Just got back from WCR and Demick told me a VERY similar story over pizza and beer. For him, it was a dropped valve seat. Engine ran wierd like yours (one side not working right), he did every FI swap and diagnosis possible, then pulled off the valve cover and saw the stuck valve.

I am no expert, I just re-gurgitate info when appropriate (IMG:style_emoticons/default/beerchug.gif)
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dr914@autoatlanta.com
post Jun 19 2007, 11:54 AM
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it is good that you are reading voltage, but check the ground leads (beige white) all connected to a male spade buss at the back pass top of the engine case just at the case half split. There are three connections two doubles and one single. The injectors ground side to side the trigger points fire diagonally. So if you have one side not working it has to be the grounds. (or possibly the other things I mentioned.)
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buck toenges
post Jun 19 2007, 05:47 PM
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Found the problem!

Had the spark plug wires mixed up on the passenger side! But now I know a whole lot more about d jet!

Thanks Guys and Gals,
Buck
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