I've pretty much gotten all the kinks worked out on my daytona here, but I'm stuck on one last problem here.

I just got my 87 daytona back together, and everything was checking out, the alternator was charging the battery (yes at Night running lights and all that too). However the next day I went to fire it up and I noticed that the gauge wasn't where it was the night before and it wasn't moving back up to the 14v it was at the night before. Since then the gauge on the dash has been intermittent at best (dropping to 10-11.5v and then back up to 14ish, and then dropping again), but it hasn't even been moving now. Looking at it, it is basically now failing to recharge the battery b/c when I check the voltage across the field terminals on the alternator I get 0v, and my Battery voltage is 11.5v or 10ish when the lights are on (which is the same voltage my dash is putting out).

What I want to know is what gets/provides power to the field coil on the alternator and how does it do that, shouldn't there always be a voltage there (3-5v when not running anything?). I've checked the connections, they are all really good and clean. and I've checked continuity of the circuit from the 2 field wire contacts @ the power module connector so I know the circuit is good. The alternator is new, so is the battery so its not those. I know that the voltage regulator is built into the power module on the fender so I guess my questions are..

1. How do I check/test that voltage regulator? Can I safely bypass it to the alternator field coil to see if its failed?

2. How does the logic module factor into all this? is there a way to check that its sending the correct signal to the power module?

2. What does each of the Field coil wires go to? From what I pulled apart, one wire turns into a large Blue Wire (at a intermediate connector) which runs to the Power Module, the other goes to a small Green wire ( at the same intermediate connector) which also runs to the same power module connector? How do you check the voltage on these individual wires to be sure they are ok? or functioning properly?

3. Does this intermittent/field coild charging failure sound like a PCM Voltage regulator problem? or a Logic Module Failure...

Any help would be appreciated, if I can iron this wiring/power problem out i'd be ready to roll for good in this car.

Thanks!

 

first make sure your wires are tight on the alternator, the computer only grounds the field wire to energize the alternator. you will want to check for power at the alt. you could always make sure the alt is good autozone will test for free.

 

All connections were good, and very clean. It turns out it was the Voltage Reg. in the Power Module. I replaced it and got the charging system back to functioning normally again ( at least for a quick while ). By swapping the power module however it ran for like 5 minutes and then just Died. ( no spark, or fuel, or anything ). I've put up another post for this problem on the board too. If ya feel like taking a look any input would be appreciated, I have a feeling my "new" aftermarker power module crapped out on me again. but take a look at my new post.

Thanks again!

 

a high current draw out of the power module will cause a failure. take your old module and open it up. look at the circuit board for burned circuit. I had a Lancer that smoked 3 power modules. then I hard wired around the burned circuit with a circuit breaker... I discovered the problem was a bad fuel pump. the current draw was so high it melted the power module circuit board. not saying it's your problem but it's the best I have without me actually coming to your house and doing all the diagnostic work for you.

 

Well the problem with this one was the voltage regulator in the power module...I replaces it with ANOTHER aftermarket one and that one blew up on me to. I found one out of an Aires in the boneyard hooked it up and everything checks out good now. All systems seem functional and no computer trouble codes.