Superformance Electrical Problem with shutting of Engine
 

Hi!

Please help me, i am in need of an advice:
Changed my Holley Carburator to a Quickfuel without choke. Was disconnection the cable from the choke and what a surprise: was not able to shut of the engine. My inginition is a MSD 6AL on a Roush427R. So it seems the ignition box needs an application as a Resistor to shut of the engine.

Was trying to take the wire from the choke to a 12V 4Watts bulb and everything was ok - was able to shut of the engine again. Of course it makes no sense to have a lightbulb in the engine compartment which is allways on - so i am searching for a solution.

It could be a solution to replace the lightbulb with a resistor. Calculating says 12 Volt 4 Watt should be equal with a resistor at about 28 Ohms. When i measure the bulb my multimeter tell me 5 Ohm. Seems i am not an electrical guru :-(
When i find the right resistor it should work again and i can take the resistor at a hidden area. The disadvantage from this solution is that the resistor allways will pruduce heat when the engine is on.

Second solution could be to take the resistor between the red light on the dasboard (alternator) but i have not tried it till now. This will have the advantage that the resistor only produces heat when the red light is on.

Can someone help me with more electrical experience or is there another easy fix for this problem?

Thanks a lot
Peter

OK, that made my morning.:LOL: You can fix the run on problem with a simple 1A-100V diode between the voltage regulator and the alternator. Here's the MSD diagram of it: MSD Ignition

I'd be curious to know: Where did your installer pull the power source for the original choke assembly that you removed?

I don't have a choke on my Holley (removed it), but as I recall, back in the old, old days, you had to run the source for an electric Holley choke from a circuit that was only hot when the engine was actually running. If you ran it from something like the accessory circuit, that was hot when you turn the key to just listen to the radio, then you burned up your choke element because it needed to have air sucked across it (from the engine running) when it was energized. I think that's what I remember, but that's a long time ago and certainly trivial. Surely it's not the same now.

It's NOT about you patrickt.... What would your wiring have to do with HIS problem?

I was musing Blas.... And since you "opened the door' to electric choke circuitry, I took it to the next level. That would be especially helpful if someone searched for the topic, don't you think?:rolleyes:

Now Blas, I know you probably don't surf the Factory Five site, but there's a nice pic and post midway down (#6) that you might like, or you might not, it's hard to tell with you....:cool:
Holley Electric Choke ? - FFCars.com : Factory Five Racing Discussion Forum

Recently I was working on a vehicle that had the electric choke attached to the (+) Positive side of the coil. This was on a Mopar that has a Holley put in place of the original Carter 4bbl and had an OEM point type ignition. It was working but I do not think that is the best place to pull the current from as it could compromise the secondary ignition. It would be better to pull the current from a switched circuit on the fuse panel.

But it's so dang convenient....:D

http://www.clubcobra.com/photopost/d...okewarning.jpg

Just have tried it with the diode but no luck :-(
The diode is ok - i have checked it with a bulb.
Was removing the charging bulb and the same...engine does not shut off.

Now i find out that the voltage regulator is not connected. There is a plug under the regulator with 4 wires. The wires are jumpered.

The cable where the choke was connected is a black/white one. It is on the same harness as the alternator but i have no idea where it ends.

The choke cable is hot when ignition is on.

Seems a constant enginge compartment light is not the worst thing.

Peter

The voltage regulator is not plugged in and, instead someone has jumpered the wires that would have plugged in to it (that mostly run to the alternator). That's got to be an after-market switcheroo by somebody -- it couldn't have come from SPF like that. What's the make and model of your alternator?


EDIT -- When you check the make and model, it's probably a single wire job. Did your dashboard charging light ever work correctly? Or not at all?

It is a single wire alternator.
I would say charging light works ok - ignition on, charging light on -
engine running, light of - engine shut of, light running
Seems ok for me.

Peter

See your messages Peter.
Your dash alternator light sould not be working with a one wire alternator unless you have a very specialized 1 wire alternator that I've heard about or a special electrical device that will allow it to work. Most cars with a one wire alternators have the VReg totally removed from the chassis and the wires taped and secured. Send me a photo of what was done to the plug and it's wiring.
Blas

Nothing wrong with a single wire, it just means that diagram in my first post doesn't apply. If you do a troubleshooting search on the MSD web site, their suggestion for single wire run on is to use a Chrysler Dual Ballast resistor. It puts enough of a load on the smaller red wire which, they say, results in the car shutting down when you turn off the key. But before I did any of that, I would check the model of your alternator and see if there is a "conversion kit" for it that the previous guy didn't use.:cool:

Have found the solution for my problem. The secound cable at my alternator is for the charging light. To put a didode at the blue-white cable (+ for charging light) was not helping. When puting the diode at the secound cable of the alternation everything work and able to shut off engine again. Sometimes it can be so easy...you only have to try out a lot...maybe it would helps to have more knowledge about electrical too :-)

Thanks a lot Patrick and Blas for helping!!!!

Peter

@patrickt - single wire alternators are usually built off of a GM core IIsi chassis , so that if you don't mind a GM alternator on your Ford engine I guess there is nothing wrong with them - :)

Technically though, on a serious note - most single wire alternator installations I have seen come into our hands, the core charge wire itself is undersized and can cause melting or fire if not upgraded to a larger gauge of wire. Many of these single wire jobs are pushing 95-100-150-200 amps and that can Kentucky-fry a 1960s vintage charge wire ( size or spec )

The original SPF harness is designed with a 65-75amp alternator in mind ( think 1965 mustang gt )

The installer should be upgrading this at time of install , if they are using a higher grade unit.

As for aiding you through this particular problem , I am sure Blas is capable at getting you where you need to be.