FBBO Gold Member
FBBO Gold Member
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- 5:02 PM
- Dec 21, 2008
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I did bypass the computer by using and old style regulator set up - getting the same, even with no wire on the main alternator terminal.The factory computer controls the alternator output. You can bypass this setup by using the old school Mopar charging system. Give me a minute to find it.
The motor is operating on a serpentine system and is a factory crate motor.Ok, thinking this through, if you get an alternator and wire it in like an old school mopar, it should not produce 20V, so this tells me that it is something specific to your application. Are you spinning it too fast (not sure this would be produce what you are seeing). I do know that I had to change pulleys on one of mine because it wasn't charging enough (had to put a larger pulley on).
Thanks for sending link - definitely going to look at it closer.
I am going to go out on a limb here and say that your "direct ground from the VR to the alternator" is not doing you any favors. Ground it to something else like the engine (assuming it has a ground to the chassis) or to the chassis itself (ensuring it is a good clean ground).
I don't have an electrical degree but I have done a lot of electrical work (because I own a Mopar... LOL). I cannot say I have ever seen a pulsating alternator, so based on reading what you have wrote, it seems like you have eliminated most sources but you may be experiencing something like a coil effect where electrical current is passing into or through your grounds. You see this in electronic equipment where the cables must be shielded.
Your #6 cable to the start should work ok as essentially the same way I do it except I go to the starter relay but in the end you have the same connection there. In a grander sense these are relatively simple, the alternator turns and produces current, the VR regulates that. I suspect it is a simple deal, but not simple to find.
Have you read this thread?
Thanks for the suggestion. Talked to Chris, nice guy, but he thinks I should change my computer, wiring harness, gas pedal, and of course would need to get a new intake and throttle body. This sounds like some $$$. I get it, he is trying to make a living, but everything on this car is already new. I just have a problem I need to solve. Wish I had a good wiring diagram...Call Chris @ hotwireauto.com he can help you get squared away.
I know this is the B body forum. Had same problem and this was my fix.This car has demons. After getting ready to go for a ride my engine won't start. All the problems I was having points to the (POS) pcm that mopar supplied with the crate engine kit. The alternator over charging - the pcm controls the voltage. The pulsating lights - maybe the pcm? Now no 12v to coils or fuel injectors. Could be a cam or crank positioning sensor, but the alternator overcharging. Of course mopar gave me a no access non programmable pcm, so I can't look for codes or run diagnostics. You just have to get a new one, and guess what - they don't make them anymore and there support sucks. So I went and signed up on a late model Challenger site thinking there has got to be a bunch of computer experts - not much help. So maybe someone on here knows what I can do. If I have to get a new PCM I would prefer one that I can access and pull codes from, and maybe tune a little. Anyone?
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