voltage reading a little low
Thread Starter
Joined: Jan 2007
Posts: 348
Likes: 3
From: Gallatin/Hville TN
voltage reading a little low After doing my swap I noticed that my voltage is running kinda low. Sometimes it reads right at 14 and some days it reads 11. I dont know if its getting heat soaked or poor grounds or what. What should I check?
Check it all. Pick your prime reference points, which I would
pick to be a PCM ground and IGN feed at the PCM connector.
Might as well do this on an 11V day. Turn on all the accessories,
A/C, etc. to get maximum electrical load.
Then chase down the ground, measuring voltage from the PCM
connector to block, battery post, chassis sheet metal etc. and
record them; you're looking for the difference which should be
nil. If you find block-chassis is different, look at the engine ground
straps at the back of the head. Block-battery, that's the big cable.
And so on.
Then you do the same with the high side, PCM IGN to fuse block
and starter solenoid-post and battery.
There's also the possibility that your car, like mine, just has an
alternator that craps out when over-hot and overloaded. Until I
pushed down the fan temps I would see the gauge fall big time
when the A/C was on in summer, after sitting at idle for a bit.
This wouldn't show as anything but depressed system voltage,
everything tight but still crappy.
pick to be a PCM ground and IGN feed at the PCM connector.
Might as well do this on an 11V day. Turn on all the accessories,
A/C, etc. to get maximum electrical load.
Then chase down the ground, measuring voltage from the PCM
connector to block, battery post, chassis sheet metal etc. and
record them; you're looking for the difference which should be
nil. If you find block-chassis is different, look at the engine ground
straps at the back of the head. Block-battery, that's the big cable.
And so on.
Then you do the same with the high side, PCM IGN to fuse block
and starter solenoid-post and battery.
There's also the possibility that your car, like mine, just has an
alternator that craps out when over-hot and overloaded. Until I
pushed down the fan temps I would see the gauge fall big time
when the A/C was on in summer, after sitting at idle for a bit.
This wouldn't show as anything but depressed system voltage,
everything tight but still crappy.
