external voltage reg power source

[mboyek]

I just installed an external reg on my 91 using a new wiring harness. I forgot to add the 12v switched source to one of the field wires, so it doesn't work.

Anyways, I was hoping someone could suggest a good +12v switched (ignition switched) source that could be tapped into without splicing into wires.

I got a spare alternator harness from a junk car and am completely bypassing all original wires and control of the alternator. I made the harness nice with terminals and plugs so the old harness did not have to be cut and can be restored easily if needed. So I do not want to splice into a power source as I want to keep it clean and easily removable.

I was thinking of using a ring terminal and adding it to the lug on the starter solenoid, but that is either constant hot, or switched to engage the starter correct?

Any ideas? I just hate hacking into the wiring harness, a splice would be easy but I need it easily reversible.

[Austrian Dodge]

i took mine from fuel pump relay (or ASD relay)!

[85lebaront2]

One of your field wires should be dark blue. That one is +12V ignition switched. This is the wire a carbureted 2.2L used to power just about everything. Just tap into it for the regulator power.

[Austrian Dodge]

i don't know what regulator he has, but i fried two of them because i wired an a-curcuit regulator like a b-curcuit...which made it run open field and fried it.

an a-curcuit regulator needs one brush connected to a switched +12V source, where as the b-curcuit regulator needs one of the brushes to be grounded...don't mix it up or you'll fry the regulator!

[turbovanman²]

Use the coil + side,

[mboyek]

Use the coil + side,

I was thinking about that at work today. Thanks

[mboyek]

I was thinking about that at work today. Thanks

..Then I remembered its a 91 with the mini coil.

I'll see what I come up with tomorrow, will most likely just tap into a wire.

[turbovanman²]

..Then I remembered its a 91 with the mini coil.

I'll see what I come up with tomorrow, will most likely just tap into a wire.

Just tap into the wire,

[Austrian Dodge]

should be the green/orange wire going to the mini coil....but check first with a voltmeter

[mboyek]

i don't know what regulator he has, but i fried two of them because i wired an a-curcuit regulator like a b-curcuit...which made it run open field and fried it.

an a-curcuit regulator needs one brush connected to a switched +12V source, where as the b-curcuit regulator needs one of the brushes to be grounded...don't mix it up or you'll fry the regulator!

What is a b circuit alternator?

I have the bosch 90 amp alternator (from a 1991). The only difference I can tell between it and the nippendenso is the bosch has less diodes in the circuit?

I wired the reg according to a wiring diagram for a 81 dodge, which is the same as one posted on the forums here a few times. I have a reg from a 81 dodge (new) with two posts, green and blue. I sourced the +12 from the coil circuit which should just be the 12v from the asd relay. It is running at 15 volts and giving check engine (41). Assuming the 41 is because I'm leaving the ecm out of the loop, but not sure why I"m getting 15 volts.

My father said it is because the older electronics used a ballast resistor to step down the voltage to the coil, there is no resistor circuit in the coil power wiring diagrams for my 91.

Basically, the VR is wired exactly the way it should be for the vehicle it came from (green vr to green field, and blue vr to blue field with a +12v splice), good grounds and power to the fuse box. I have new wires all around, double checked the continuity and grounds.

I ran out of time and this will sit for a while now but it makes no sense to me why I can not copy a circuit that has been used successfully for a few decades. All thats happening is the VR is grounding the green field wire, which would allow 12v across the fields, generating power. Then it should cut the ground, opening the field and generating no power. Is this correct? is my alternator evil and simply not compatible with this old simple stuff and in need of varying voltage feeds? I have tested the alternator and battery numerous times now, in and out of the vehicle. I know its the ECM's VR giving me troubles. I want it gone.

Before I wired up the VR (vr733 I think?, used in all mopar 80-87 or so) I checked the fields from the ecm and the blue field wire was grounded ignition off and +12 ignition on. Exactly the way the new vr is wired. This is a 91 with a fuse box, no sketchy fusible links. I also added some extra grounds at this time.

[mboyek]

And, btw, this thing runs beautifully on a fresh battery with the fields open (not charging, running only on battery power). It seems my map sensor hates voltage spikes and makes it run like poo (code 13 for a while now, just came up with a 14, hope I didn't fry it with 15.8 volts).

[turbovanman²]

I did this to a 95 Neon, worked perfectly, right one of course. Ballast not needed, of course,

http://www.turbo-mopar.com/forums/sh...95&postcount=4

[Austrian Dodge]

it's not the alternator which is a or b circuit but the regulator. i bought a universal one from cpgenerators.com and had a little chat with eric. he explained me that a and b circuit stuff.

i made some high tech diagrams LOL
A-circuit:
http://img413.imageshack.us/img413/7423/acircuithh1.jpg


B-circuit:
http://img519.imageshack.us/img519/8308/bcircuitir3.jpg

[mboyek]

it's not the alternator which is a or b circuit but the regulator. i bought a universal one from cpgenerators.com and had a little chat with eric. he explained me that a and b circuit stuff.

i made some high tech diagrams LOL
A-circuit:
http://img413.imageshack.us/img413/7423/acircuithh1.jpg


B-circuit:
http://img519.imageshack.us/img519/8308/bcircuitir3.jpg

Thanks, this just verifies I have everything correct.


I just got an opportunity to start working on this car again.

I have a "a" circuit voltage regulator. I have verified that by studying the wiring diagrams for vehicles it was used on. I have that exact wiring set up, everything simple, correct and tested.

I put extra grounds on, assuming mine were not up to par. The alternator case is grounded to the battery (stock) and grounded to the passenger frame, using the same point as the VR. There is also an extra ground from that point to the block.

The VR is charging at 14.8v. Steady. Is this too much??

I have a code 41, assuming the computer reads open fields because its flying blind and connected to nothing. Will this put me in limp home mode? I'm also chasing a map sensor code which IS putting me in limp mode, I was under the impression it was caused by too much voltage, but if 14.8 volts is ok, I will start fiddling with other things in that circuit.


This damn thing is maddening. I suppose it could be the alternator, but I have tested it so many times and it tests good. I was thinking the VR would put me at a steady 13.5 or 14 at the highest. If I disconnect the battery, it runs at 15v.

I'm pretty close to trying another ecm and going back to stock control. Just need to find a good manual tranny 91 ecm for a N/A 2.5. and I really don't want to have to burn a chip and socket a board to get this thing right.

Thanks for the links again, its all correct, it just doesn't work.

[mboyek]

Hmm, FSM says 14.34-14.95v MAX, but thats with ambient batt temp of 0-50^F. And the external reg does not use temp control.

I'm going to fiddle with spare MAP's and different diameter vacuum lines, maybe 14.8 volts is acceptable?

[turbovanman²]

14.8 is a bit high but its acceptable and the code 41 won't put you in limp mode.

[Austrian Dodge]

14.8V seems to be correct...but you don't want to go higher!

[mboyek]

14.8V seems to be correct...but you don't want to go higher!

Alright, fixed the map problem with a spare map, but it does run 15v with headlights and radio on. its mostly 14.8,but jumps sometimes.

[black86glhs]

14.8v should be fine. I'de like to know if the amperage moves up or down like it should depending on load. The computer will should take whatever is coming in and drop it to 5 or 12 volts, depending on the circuit requirements.

[mboyek]

14.8v should be fine. I'de like to know if the amperage moves up or down like it should depending on load. The computer will should take whatever is coming in and drop it to 5 or 12 volts, depending on the circuit requirements.

I don't have an ammeter in the circuit. The FSM does say to use one for diagnostics, but I do not have a carbon pile rheostat.

So, the ecm can take 15v and output 5v for the map, even if the voltage regulator is not operating properly?