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FD idle and electrical issue

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Old 01-04-24, 09:16 PM
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FD idle and electrical issue

I'm at my wits end because I hate wiring. I'll try and keep it simple with as much important detail in chronological order over the past year. Installed sake bomb fuel pump harness extension that protects from voltage drop. Followed instructions to the letter double tripple checked. Car wouldn't start. Put the original back on car started just fine. Month or two later. Car started randomly cutting power on the road, backfiring. I'd stop turn it off and it wouldn't start again for a while. Now a year later the car starts but idles rough and backfires. As well as now have a violent parasitic draw and the ac works but the ac lights don't and the head unit doesn't come on.
Parts/test list
Rebuilt to 140amp alternator pushes good
new battery in the trunk tests good
Power fc
Tested all fuses good
changed ratty engine ground wire and idles a little better but still bad

I see the other posts similar to this but can't figure out which is best to listen to.






Old 01-04-24, 09:19 PM
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do you know how to use a multimeter?
Old 01-04-24, 09:22 PM
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Originally Posted by FDAUTO
do you know how to use a multimeter?
yes i have tested the alternator output, the battery while running, the battery disconnected on its own and as well as pulled almost every fuse one by one when the key is off and still watched the voltage drop point by point quickly.
Old 01-04-24, 09:24 PM
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Originally Posted by JayroeSpeed
yes i have tested the alternator output, the battery while running, the battery disconnected on its own and as well as pulled almost every fuse one by one when the key is off and still watched the voltage drop point by point quickly.
even got under and disconnected the starter and then it seemed to have stopped the draw but hooked it back up and it wasn't dropping anymore. Then tried to start and test again at a later date and it started dropping again
Old 01-04-24, 10:18 PM
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You look for a draw by watching amps... not volts.

Set your multimeter to amps and do everything you did again but start with the 2 pin plug on the alternator
Old 01-04-24, 10:44 PM
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Originally Posted by FDAUTO
You look for a draw by watching amps... not volts.

Set your multimeter to amps and do everything you did again but start with the 2 pin plug on the alternator
well dang that makes alot more sense ok 10 Amp mili Amp or ųamp setting and DC right? And what pos an neg to both pins or pos to one or the other an neg to a ground? Thankyou!
Old 01-04-24, 10:51 PM
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My friend lmao this why I asked if you knew how to use a multimeter

Any youtube video will be able to walk you through the process. chris fix has a really good video on it but feel free to look at others
Old 01-04-24, 11:13 PM
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Originally Posted by FDAUTO
My friend lmao this why I asked if you knew how to use a multimeter

Any youtube video will be able to walk you through the process. chris fix has a really good video on it but feel free to look at others
ok I'll look around for the answer to the rest of those questions thankyou
Old 01-08-24, 03:16 PM
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For rough idle and backfires (I assume it's popping rather than backfires), check for vacuum leaks in the UIM area. Another possible cause would be timing/ignition related - a damaged spark plug wire, a bad ignition coil, bad CAS sensor connector (less probable).
You can use a timing light device to check wires/coils.
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