5.0 carb/battery problem in an LTD Crown Vic

[Crankcase]

Ok, I normally don't ask for tech help, but this time I am stumped.

I have a battery drain on an 84 LTD Crown Vic with the 5.0. if I let it sit overnight, the battery would drain down to .28 volts from 13...

I did the usual fuse pulling /troubleshooting with no avail until I asked SVO yesterday what he thought it might be.

He pointed me in the direction of the Regulator mounted on the fender....So I took a look at the connector there. This is what I found:

The wires were frayed / cracking / bare etc...and the weird part is, this is the only place on the car like that.

Anyways, I unplugged the harness from the regulator, and there was still a power draw.

 

[Crankcase]

Well, I set up a test light between the disconnected Positive cable and the battery post. It lit up bright. I still had a major drain.

I then next disconnected the main lead that runs off the starter solenoid and powers the ignition coil, regulator harness, and alternator. The light went out.

Well, I found the individual wire that is causing the drain....It goes to this:

 

[Crankcase]

....And a close up with the part numbers....here are My questions:

What is this? Some sort of throttle postion sensor?
Is it replaceable without tearing down the carb?
Is it expensive?

Thanks in advance LOL

 

[Howard]

My guess is electric choke flap control. Basically a small bi-metallic strip that warms up and gradually takes the choke off. Easily replaceable.

 

[Crankcase]

Hrm. I am going to take a look at it again today....Where are all the 5.0 experts? LOL!

 

[jimbo74]

none of those guys know about carbs..... im with howard... there are all sorts of wierd carb things....... on my truck, mine uses a thermostatic air valve t odetermine the temp for cold idle or not......

 

[IAmTodd]

What's a carb?

 

[Eneurb]

I don't see how the electric choke can be causing a draw... it only has one wire going to it, so therefore something has to be keeping it powered on.

 

[Oversquare]

Yes, that looks like the Choke for the carb. Check to see if the wire is cracked/shorted/etc anywhere. Does the light go out when you disconnect the wire?

Will the car cold-start and idle with the wire disconnected? Will it warm-idle when disconnected?

The electrical wire is a supplement to the heating coil that controls the choke. You should be ok without it. My guess is that the relay inside the choke, or a relay somewhere else, has gone bad (if the wire checks out good). You could probably pull another one from a junkyard if you need one. They should be easy to replace - pending any stripped/rusted/seized threads.

-Brad

 

[Crankcase]

The wire is basically run straight to it with no cracks or relays or anything. The internal parts must be messed up. Somehow it is grounding out to the carb.

 

[Eneurb]

Is there 12v at that wire Key On Engine Off??

 

[Crankcase]

There is power there in any postion, lol it is basically hardwired to the battery!

Here is a pic, the Green wire on the + side of the starter solenoid turns into a black covered wire, then a grey wire shoots off to the thing on the carb. The rest of the wire continues to the Ignition coil, Alternator, and Regulator.

 

[Eneurb]

I don't have very much real life carburetor experience, just what I've learned in training, but I don't think that it is supposed to be powered up all the time, just when the key is in the run position.

 

[Crankcase]

Ok, after tearing into it today...I found where the grey wire goes.

It turns out it goes to the back of the alternator. In my diagram, the blue wire is the main feed from the alternator.

The grey wire comes off one stud on the alt and splits...one wire goes to the "S" termianal of the regulator. The other goes to the choke deal on the carb. If I disconnect the Regulator, there is still live power going to the grey regulator wire end and the carb from the stud on the alternator.

Any ideas why that stud would be hot on the alternator when turned off? The other stud, which is the orange wire, is not hot . The picture I drew shows the exact psotions of the studs on the alt.

This is driving me nuts, as I am not sure what is bad now? Ideas?

 

[Howard]

Looks like something has gone wrong with the alternator wiring. Strip it down and see.

 

[Eneurb]

I'd say the same. Maybe just overlay the grey wire temporarily, and see if you still have the same problem. But I do believe it's a pretty accessible wire harness.

 

[performancenut]

How about disconnecting the choke wire completely and replacing the electric choke coil with a manual cable that ends in the passenger compartment.

 

[CDW6212R]

I agree with the others, that you have a power source that should only be live with the ignition on. Unless someone knows what these alternator wires are, take it to an alternator shop. Ask them to check the alternator and the starting wires. The cost for a simple diagnoses like that should be reasonable. Good luck,
Don

 

[old mechanic]

Before you replace the auto choke unit, replace the bad wireing and the connector first as they need replacing anyway. The connector could be grounding out even when disconected from the regulator. Or the alt may be shorting out internaly if the juice isn't supposed to be on all the time ( I can't remember) to the carb and alt.
On another note, save your self some trouble and replace the solinoid. It will go and when it does it will shut you down and your lights will not work. Something many Ford owners found out the hard way, at night on a sharp curve where no one can see you.