No 12v reference coming from pcm for cam and crank sensors
10-30-2021, 08:36 AM
#1
Teching In
Thread Starter
No 12v reference coming from pcm for cam and crank sensors I have no 12v reference coming from my pcm to my cam and crank sensors I thought it might have been a bad ground so I redone all of my pcm grounds and routed them to the rear of my chevy ii. I have my coil grounds going to the back if the block. everything else seems to be working correctly. I did get power to them briefly for whatever reason and the car tried to bust off so I know if I can get power to it constantly this would solve my no start issue. Heck could I just run a wire straight to the connectors lol? Thanks for any input.
10-30-2021, 01:28 PM
#2
You probably should trace it all the way back to the ecu. See if you have the volts there.
It's generally 11.7v.
If it's there, you have an open in the wiring.
I would also use your ohm meter and measure resistance to ground on that wire. Do it with the ign off.
If it's near 0 ohms you have a short in that wire.
Ron
It's generally 11.7v.
If it's there, you have an open in the wiring.
I would also use your ohm meter and measure resistance to ground on that wire. Do it with the ign off.
If it's near 0 ohms you have a short in that wire.
Ron
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Mouse9419 (10-31-2021)
10-31-2021, 06:27 AM
#3
Teching In
Thread Starter
I checked it at ecu I'm not getting 12v there either. So now my question is might I have a bad ecu. Or could I possibly run a direct wire to my cam and crank sensors.
10-31-2021, 08:28 AM
#4
First, check all of the ECM fuses. There are at least two. One powers the ECM internals and the other one provides power for the sensors. It sounds like there may be one blown fuse. If all of the ECM fuses are good, then check for power on all of the power input leads to the PCM. Again, one source (can be 2 or more wires in the harness) is for operating the PCM internals and (an)other source(s) (which can also be more than one wire in the harness) are for powering the sensors.
11-09-2021, 05:14 PM
#5
Teching In
Thread Starter
Ok I figured out this issue. I had ran 12v from the fuse block to the alternator and installed a resistor to try to get my alternator to charge. I removed the wire and connected it the correct way and got voltage back. But this still isn't fixing my issue of no spark. I have the coils rain to cranking 12v I have good grounds and I've installed new coil packs. Plugs and wires. Anything else I could possibly check? Thank yall for all the feed back much appreciated I would have never thought the alternator would have anything to do with cam and crank sensors.
