Alternator issue with Weber electric choke

[86dxhatch]

Hi all, lets start with the basics. I've got an 87 dx sedan that I converted to a Weber 38 due to a soaring idle with the stock carb. Didn't feel like messing with troubleshooting the stock system, so I got a 38 since how great the 32/36 on my hatch has been.

Anyway, after changing to the Weber, I've noticed my battery light on. I've only had the car on the road for a couple weeks now and it only took a week for my (newish)battery to slowly die. I recently bought DBMasters old alternator so I figured I'd try it out to see if maybe my alt was bad.

So I Make a harness for the FI alt, swap it out and hope for the best. When I first started the car the light was off but the choke wire was off of the carb and must have grounded because the it only ran for a short while then died. I looked through my service manual and found that the choke + is on the same circuit as my fuel pump. Found a blown #1 fuse, the car started and I thought my problem was solved. But no, my batt light is back on.

I figured maybe the battery was still low and the light will go out. Didn't happen. I started poking around and unhook the coke wire, and voila... I hear my engine load up and the alternator whirr, so the alternator wasn't even engaging. With the wire unhooked, the batt light is still on but very dim upon startup but gets brighter as i drive :wtf: I plug the choke back in and it comes on full bright, and the alt stops loading up.

Anyone else have alt issues with electric choke?

[86dxhatch]

Let me clarify a bit. A little too much going on In my first post I believe.

When I plug in my choke wire, the battery light is on full bright and my alternator in not working.

As soon as I pull the choke wire off, the alternator starts working. The thing is, even with the wire off and the alt. loading up my battery light is still on but about half as bright.

The service manual says there could be a short in the choke heater but i don't think this is the case since its been a few days now since I've had the wire off, and the bat. light hasn't gone away or gotten any dimmer.

[2oodoor]

well, essentialy the choke heater is an engineered controlled short by design, like a light bulb:D
It shouldn't be a direct short though, you may want to take the choke heater out just to make sure the coil element isn't damaged or some how grounding fully to the carb body on the power hot terminal end.

Other than that, it sounds like a diode is fried in the system somewhere, probably the internal regulator but don't condem that yet..

The choke wire is related to the field circuit of the alternator isn't it? that's why when the regulator goes out sometimes the choke heater doesn't work anymore.
I've also observed that the wire harness under the intake has several open terminals left after a conversion, make sure none of them grounded out or are connected to the wrong thing.
The white/blue wire off the alt harness is for the choke heater and some of the other things in that harness under the intake.

[lostforawhile]

the choke wire doesn't go to battery plus, it goes to the alternator light circuit wire, the white/blue wire. it should be the same color at the old choke wire, when the alternator isn't charging, that wire is negative, when it's charging that wire becomes positive, it's the same circuit on FI or carbed, same color, the only difference between a carbed alternator and a FI is the extra wire that allows the computer to reduce the alternator load

[lostforawhile]

the white/blue wire goes into the alternator plug,then there's a split, and it goes to the choke,it also goes to the multi function box under the dash, this tells the oil pressure flasher to work, and other things, and it also goes to the carb computer, under the seat, make sure one of these wires isn't shorted out.

[86dxhatch]

This ^^ In the last week I've had the oil pressure light come on flashing at start-up. I just turn the ignition off, start again and it goes away. When I get some time after work and its not raining I'll start poking around the carb computer and double check under the hood.

I take it the multifunction box is probably buried in the far reaches of the under dash oblivion? Any pointers to where this is?

I'll start digging through my service manual and see if I can trace the whole white blue wire circuit.

[2oodoor]

I wouldn't think the multi function box needed any attention quite yet, not until you are sure there isn't a wire goof along that harness under the intake. What did you do with the carb base heater wire that was on the oem carb? Did you mix up the oil sender wire with another wire?

[86dxhatch]

I never messed with the oil sender wire as far as I know. I just have the carb base heater wire unplugged and laying there with all the other unused connectors. Just reading the service manual and it says an open in the base heater wire is also suspect. Looks like it just stopped raining, I'll go have a look at the unused connectors. I can't remember which connector it is, but I'll jot the wire colors down and try to figure it out. Thanks

[86dxhatch]

So I found a total of 4 unused harnesses.(coming from the wire loom under the intake)

1 wire - green/red stripe

2 wire - green/black stripe + black, black + red, and a heavier gauge black + white.

Then there is the white/blue stripe choke wire,
white/red stripe oil sender I assume,

and a white or yellow/green stripe hooked to intake right below the carb.
What is this ^ wire to? .....temp sensor?

None of the connectors appear grounded and no nicked wires as far as I can tell.

[lostforawhile]

So I found a total of 4 unused harnesses.(coming from the wire loom under the intake)

1 wire - green/red stripe

2 wire - green/black stripe + black, black + red, and a heavier gauge black + white.

Then there is the white/blue stripe choke wire,
white/red stripe oil sender I assume,

and a white or yellow/green stripe hooked to intake right below the carb.
What is this ^ wire to? .....temp sensor?

None of the connectors appear grounded and no nicked wires as far as I can tell.
the heavy black/white was to the EFE heater under the factory carb, the oil sender wire should be going to the top of the oil filter base, the wire right under the carb is your temp sender wire for the gauge, it should be attached to the sender screwed into the coolant passage in the intake, there is another one on the back of the block, another sender, it's for the carb computer, it has a push to lock green connector, it's screwed into the back of the block itself. It's a thermo sensor just like whats on the FI cars it only tells the carb computer what the coolant temp is.

[86dxhatch]

Well, I wont need any further assistance with this electrical problem........... I had a large dog run in front of me @ 60mph and swerved to miss him, I lost control and put my car into the bushes/trees. The whole drivers quarter panel is mangled, hood, bumper, windshield. The drivers wheel is pushed back to the rear of the wheel well, and the area under the quarter panel that it attaches to is also done for. Between all of the repairs it would need it will cost me more than I have into it and what it's worth.

Looks like I've got a 94,000mi drive train for the hatchback.

R.I.P 87dx sedan :crying: