Idle speed control motor

[styxplo]

I have a Ford TBI off of a 1986 ford mustang. I'm putting it on a ford bronco II with a 2.8. My question is I'm not sure what type of idle control is on it. The replacment is a standard motor products and there calling it an idle speed control motor. It has four wires. Originally I thought it was a PWM idle controller, but now I am not sure. Is there a way to determine the type. It is mounted on the side of the throttle body and makes contact with the actual throttle linkage like a regular fast idle solenoid would. I looked at the wiring diagram and one wire is ground and the other three go to the computer. Thanks

[DonTZ125]

That's ... bizarre. 4-wires is normally a stepper motor, but if there are only 3 wires going to the box ... ?

Can you post up the wiring diagram?

[DonTZ125]

A quick Google of various pics for "idle motor 1986 ford mustang" shows a lot of TWO-wire devices. Are you sure you have the original TBI? (caveat - I'm a bike guy; I'm learning this car stuff as I go! )

[styxplo]

Here is the wiring diagram for the idle control motor

[kjones6039]

Just about the time you start thinking you have seen everything and...... wth is that? It certainly isn't a motor in the sense I'm used to.....

I googled a little too and I'm thinking it looks more like a pwm unit that anything...... Although that schematic clearly says "IDLE SPEED MOTOR".....



Ken

[styxplo]

Is anyone aware of a way to test to see which type mine may be? Also I heaven't really found any information on how to wire up a PWM idle controller if it is in fact one. There is information on how to wire a stepper IAC, but I can't find any for a PWM

[kjones6039]

Can you possibly post up a couple pics of the unit and connector? Does the valve have any numbers on it? If so, they might be very helpful.

Ken

[DonTZ125]

Is anyone aware of a way to test to see which type mine may be? Also I heaven't really found any information on how to wire up a PWM idle controller if it is in fact one. There is information on how to wire a stepper IAC, but I can't find any for a PWM

It's in the manual - wayyy down at the bottom. IF that's a PWM valve / solenoid actuator that has a grounded body, then you need to get out the multimeter. Determine which pin goes to ground on the harness; the other three are your coil terminals - open and close at the end, +12v in the middle. If none of the pins make sense for this, then something else is going on.

It occurs to me this COULD be a stepper device, if the motor itself contains an H-bridge.

[styxplo]

I will ring it out and see what I come up with. I can take a few pictures also and I will post them. When I assembled the V3 board I assumed it was a PWM style because it talks of Ford using this type and I knew it wasn't just a fast idle solenoid. I added a tip 120 transistor and did not install Q20 D8 and jumper R39 as per the instructions. As for the actual wiring of the idle motor (which pins I wire it to on the megasquirt) , I can't find anything.

[kjones6039]

It occurs to me this COULD be a stepper device, if the motor itself contains an H-bridge.

My recollection, without any further research, is that those motors with an H-bridge, generally have 5 wires! Although I may well be wrong on that point!

Just thinking out loud here........

Ken

[DonTZ125]

I will ring it out and see what I come up with. I can take a few pictures also and I will post them. When I assembled the V3 board I assumed it was a PWM style because it talks of Ford using this type and I knew it wasn't just a fast idle solenoid. I added a tip 120 transistor and did not install Q20 D8 and jumper R39 as per the instructions. As for the actual wiring of the idle motor (which pins I wire it to on the megasquirt) , I can't find anything.

From the Extra manual ...

Bosch-valve.JPG

It occurs to me this COULD be a stepper device, if the motor itself contains an H-bridge.

My recollection, without any further research, is that those motors with an H-bridge, generally have 5 wires! Although I may well be wrong on that point!

My thinking is that you have (on the ECU) +12v, Pin A and Pin B to actually drive the H-bridge, plus GND to the harness.

5-wire motors (in my experience) are dumb servos, with Terminal A and Terminal B on the actual driving coil, plus a 3-pin pot for feedback (like a TPS). The actual H-bridge switching power to A and B is in the processor / controller.

[styxplo]

The diagram you posted said it was from the "EXTRA" manual. I can't seem to find this manual

[kjones6039]

The Extra manual is located here.

Ken

[Matt Cramer]

I suspect this may be a DC servo motor with position sensor - which is currently not supported.

[styxplo]

At this point I'm kinda just experimenting with this thing out of curiousity. I pretty much decided that I'm going to just use a simple fast idle solenoid even though I will lose some of the fine control. There are 2 yellow wires that if I hook up to +12 and ground it goes all the way out until it must reach an internal limit because once it strokes all the way out it stops and no longer draws current. if i reverse the wires it goes all the way in with the same result. No curernt draw at end of stroke. I expected to see some sort of change on the other two wires as it was moving, some type of feedback, but didn't. I read the black wth white stripe wire, which the diagram shows goes to ground, and I expected it to be in common with motor case, but it wasn't. I hooked the other 2 wires across the battery (very breifly) and could tell one of them seemed to be a short to ground from the spark and warmth in the wire, but they both read open to ground. I think I'm gonna take it apart and see what makes it tick. I finally have everything wired up and went to plug in my megasquirt when I noticed the pink bag my daughterboard was in had a bunch of teeth marks in it. Yeah the dog got to it and ate it. $130 and a wait on shipping because of the weather.