Garage Storage Organization and Garage Cabinets

SOMETHINGCLEVER · **trouble regulating voltage...T2 car**

New to turbo dodges.....looking for a couple ideas.

A buddy just picked up an 87 charger GLHS....car ran well when purchased...he put about 30 miles on it before he started having some problems. Car sat outside for 2 yrs before he bought it...but was started and ran occasionaly by the previous owner.

PO told us it would occasionally sputter and he would have to hit the passenger side kick panel and it would clear up. Well...it started sputtering after the 30 miles my buddy drove it...we pulled the kick panel to reveal the logic controller. It was a NAPA remmanned unit. Pulled the 2 plugs to find water in them....cleaned, dried, and put back together with dielectric grease.

Car started up and ran smooth.

At this point we noticed his volt gauge was reading low. So i checked the voltage at the battery and sure enough...it wasn't getting a charge from the alternator. A quick trip to autozone and an alt test showed it was junk...got a remmanned unit and we're on our way. Swap alternators and start the car up....14 volts at the battery....cool. Had him hit the lights and heater...still 14 volts. Cool. Drive the car outside in the parking lot and his gauge dropped down after 2 minutes of driving....checked volts at battery and alt not charging...hmmmm..so we gave up for the night.

So the car sits outside in the rain for a couple days...and we have to jump start it...starts up fine and runs good...getting 14volts...car idles for 2 minutes....all is good. Starts to give it gas and the volt gauge increases with engine rpm...goes up to 17 or so volts....not good. Shut it down, pull the REMANNED NAPA power module and clean both plugs and a couple battery grounds to the fenderwell. Both plugs in power module are wet and grounds are rusty.

Start car back up after re-ass'y....14 volts....ok....idles for 2 min....holds pretty steady. Gives the car some gas...and the volts increase up to 17 or even 18. (now in the initial car start up...the car can be rev'd and the volts DO NOT increase with rpm...stay at 14...then after about 2 minutes....it can no longer regulate volts.)

What the heck?

So i'm thinking the following.....bad NAPA remmaned power module

Or bad NAPA remmaned logic controller

Or bad wire somewhere. (not sure of this one)

Any thoughts/opinions/suggestions welcomed, and sorry for the long read.

charger R/T · 01-24-2006, 07:36 PM

I'm not familiar with the older cars with the 2 units. But I think the voltage regulator is in the logic module on your car. Someone else might chime in with better info or do a search on here there are many threads on this. I wouldn't blame napa if it had water in it. I would find out and fix how water is getting into it and fix that then get another module. They pop up here in the for sale adds. I also think there is a sticky on how to wire in an external voltage regulator in the electrical section.
Tim

SOMETHINGCLEVER · 01-25-2006, 07:54 AM

I believe i read that both the power module and logic controller regulate voltage. I don't think either one (if bad) is due to it being from NAPA, but bad because they have been saturated in moisture.

It seems the next logical step is to replace each one at a time...and see the result. If it doesn't work, i can always return it.

I dont' feel it's a wiring issue (meaning poor connection), as the voltage would always read 14-15 or lower....not higher like i've been seeing.

I don't want to wire in an external regulator...it would be nice to get all the factory stuff working.

jdawg · 01-25-2006, 08:05 AM

Its probably leaking water from the cowl area. From the factory there should have been a plastic bag around it.

charger R/T · 01-25-2006, 07:02 PM

it doesn't use both just one. A search here should find out for sure which one. High voltage can be a wiring issue. The 2 field wires work this way. 1 is hot from the key. The other gets a ground from the computer. It varies the ground to change voltage. If that wire shorts to ground the result is high voltage.
Tim

charger R/T · 01-25-2006, 07:11 PM

here check out this thread
How To: External Voltage Regulator w/pics?
Tim

SOMETHINGCLEVER · 02-20-2006, 03:54 PM

Just figured I'd update this....problem turned out to be a bad PM. Everything else in it worked fine except it couldn't regulate voltage. We're going to wire in an external unit for $15 as a remmaned PM is $100.

Thanks to all who helped.

taco502001 · 03-05-2006, 02:23 PM

lol i was about to say that as i had to wire up an external voltage reg but i think there might be some other circuits fried in my power module

GLHNSLHT2 · 03-05-2006, 02:44 PM

the regulator is in the PM, but the LM tells it when to turn on and off!

The Reman LM's and PM's are JUNK! The LM's have a real crappy boost schedule and who knows what their fueling is doing. Here's what I'd do. I'd go down to the j-yard and find a nice 87 turbo car and pull the PM out of that for $5

Or find one on the list/forum. While you're at the J-yard pull the LM out of it, have someone socket it and burn a Stage 2 MP calibration on it and you're set. Mid to low 14's right there. 3" exhaust and you're looking at 13's. The NAPA remanned puter in a VNT car would only give it 7psi until 4500rpms then it'd give 11psi. Sad. When a stock VNT would hit 14psi. Get those puters out of there. Why hack up the wiring?