VIN 4519: 14-year "garage find"

[Rich_NYS]

I don't know what the idle speed microswitch does, but since the idle doesn't change when I toggle it, I tested it with an ohmeter (seems fine.)

I have some kind of cold start issue, so I tried the plug swap. I had to remove the WUR so the the CSV plug would reach....seems to have no effect.

[Jonathan]

As far as I know pressing the idle switch does nothing to the idle ECU or idle motor. It should add the vacuum advance on a warm engine and you should hear or see that change the idle for a moment. Have you verified you get vacuum in the hose going to the advance on a warm engine? Disconnecting the electrical plug on the advance solenoid also should let vacuum get to the advance.

I don't know what the idle speed microswitch does, but since the idle doesn't change when I toggle it, I tested it with an ohmeter (seems fine.)

I have some kind of cold start issue, so I tried the plug swap. I had to remove the WUR so the the CSV plug would reach....seems to have no effect.

Please look on about page 78 of the technical manual for how the idle speed system works.

Dave, for someone that designs and sells replacement electrical components to the DeLorean community, I'm a little shocked and frightened that you don't already know this.

[Rich_NYS]

Please look on about page 78 of the technical manual for how the idle speed system works.

Dave, for someone that designs and sells replacement electrical components to the DeLorean community, I'm a little shocked and frightened that you don't already know this.

Thanks Jon, I read through that section and it's fairly clear now. Thanks even more for reminding me to use the TM, I have 2 hard copies and have overlooked it as a valuable resource.

I'm digging into the TM now, and will try to resolve my cold start issue.

Based on what I'm reading, I think I should read an electrical signal at the ISM plug with the key on & idle speed micro switch pressed. I have no voltage at the plug, so maybe that's where I should be "picking up the trail."

Thanks again for "teaching this man to fish," yo!

[JETS 81 DMC]

Rich,

Just a thought and my .02

Have you checked electrical connections for corrosion to make sure you are getting 100% contact?
I would do that first then check switch with a multi meter to make sure it is functioning.

You are making some great progress. How is your arm? Close to being back to 100%

[Bitsyncmaster]

Please look on about page 78 of the technical manual for how the idle speed system works.

Dave, for someone that designs and sells replacement electrical components to the DeLorean community, I'm a little shocked and frightened that you don't already know this.

That statement that the idle system is only operational when the idle switch is closed is not true. Pull a wire off the switch and start up your cold engine and see that nothing changes in the engine warm up idle speed. After the engine warms up you will get ignition advance at idle which may cause the idle motor to run out of control to bring the idle speed down but it still is trying to hold that 775 RPM.

[Ron]

$.02

Rich, I think you meant 500 to 700, not 5000 to 7000.

If you are sure there are no vacuum leaks, check out the 3 switches (see below).
If no luck, I'd put a CIS fuel pressure gauge on it and check out the pressures...the WUR/CPR affects the idle greatly. It basically acts like a choke in a carb system.

Full Throttle (or WOT "Wide Open Throttle") Switch-
Disconnected, the B (Black) wire should show Ground and LG wire should have 12V, with key ON.
Closing the switch forces 50° - 60° CO Dwell, by grounding the LG wire, thereby enriching the AFR. This will change the engine's RPM/sound IFF the coolant is above 59°F. (Check warm because the Lambda Thermal Switch also forces the dwell to 50° - 60° when below 59°F...)

Kick Down Switch (Used with Automatic Transmission only)-
Disconnected, the B wire should show Ground and LGG wire should have 12V, with key ON.
Closing the switch requests a down shift by grounding the LLG wire.
Has no direct effect on the engine.

Idle Speed Switch-
Disconnected, the B wire should show Ground, the BU and BLG wires should both have 12V, with key ON. A diode in the BLG wire isolates the two circuits.
Closing the switch enables the Idle ECU and disables the Vacuum Advance, by grounding the two circuits. (The Thermal Vacuum Control Valve also disables the Vacuum Advance whenever the coolant is below 104°F...)

If you raise the idle manually just enough to open the switch and hold it STEADY, pressing the switch will change the engine's RPM/sound, warm or cold (engages the Idle ECU).
If the engine is warm (and held steady above idle), there should be vacuum at the distributor. Then pressing the switch will energize the Idle Solenoid and block the vacuum at the distributor.

[Rich_NYS]

Rich,

Just a thought and my .02

Have you checked electrical connections for corrosion to make sure you are getting 100% contact?
I would do that first then check switch with a multi meter to make sure it is functioning.

You are making some great progress. How is your arm? Close to being back to 100%

Thanks Mr. Jim,

I checked the connections where I tested components, but not throughout the entire circuit (i.e bulkhead connections.) I'll do that asap, then will test for voltage as I go.

I'll familiarize with CIS and figure it out. I'm reading the TM, searching the forum, and will study the schematics.

At this point, it appears I only have a cold-start issue (hard start, surges wildly...etc,) but runs very well after about 5 minutes. I'm thinking it can't be too difficult to figure out.

As I learn the Kjet system, I continue to believe those who criticize Bill and/or carb conversions are jealous haters. Lol!

My arm is doing ok, thanks....I'm only about 50% recovered, so working on some things are a struggle.

[Rich_NYS]

$.02

Rich, I think you meant 500 to 700, not 5000 to 7000.

If you are sure there are no vacuum leaks, check out the 3 switches (see below).
If no luck, I'd put a CIS fuel pressure gauge on it and check out the pressures...the WUR/CPR affects the idle greatly. It basically acts like a choke in a carb system.

Full Throttle (or WOT "Wide Open Throttle") Switch-
Disconnected, the B (Black) wire should show Ground and LG wire should have 12V, with key ON.
Closing the switch forces 50° - 60° CO Dwell, by grounding the LG wire, thereby enriching the AFR. This will change the engine's RPM/sound IFF the coolant is above 59°F. (Check warm because the Lambda Thermal Switch also forces the dwell to 50° - 60° when below 59°F...)

Kick Down Switch (Used with Automatic Transmission only)-
Disconnected, the B wire should show Ground and LGG wire should have 12V, with key ON.
Closing the switch requests a down shift by grounding the LLG wire.
Has no direct effect on the engine.

Idle Speed Switch-
Disconnected, the B wire should show Ground, the BU and BLG wires should both have 12V, with key ON. A diode in the BLG wire isolates the two circuits.
Closing the switch enables the Idle ECU and disables the Vacuum Advance, by grounding the two circuits. (The Thermal Vacuum Control Valve also disables the Vacuum Advance whenever the coolant is below 104°F...)

If you raise the idle manually just enough to open the switch and hold it STEADY, pressing the switch will change the engine's RPM/sound, warm or cold (engages the Idle ECU).
If the engine is warm (and held steady above idle), there should be vacuum at the distributor. Then pressing the switch will energize the Idle Solenoid and block the vacuum at the distributor.

Excellent info...thanks man, I'll check these things asap.

BTW, so far I think my head gaskets are ok.

[Ron]

$ .03

Just check the voltages at the components. If they are OK you are wasting your time checking the rest (except for intermittent problems...or preventive maintenance). Use an ice pick tester instead of a volt meter. (They don't show if the circuit will handle the load, E.G., a meter may show 12V on a circuit when it will not light a mini light bulb...)


Did you pressure test the coolant system?

[Rich_NYS]

$ .03

Just check the voltages at the components. If they are OK you are wasting your time checking the rest (except for intermittent problems...or preventive maintenance). Use an ice pick tester instead of a volt meter. (They don't show if the circuit will handle the load, E.G., a meter may show 12V on a circuit when it will not light a mini light bulb...)


Did you pressure test the coolant system?

Roger that on the test light, I have one and will start using it instead of a VOM.

Clarification: "checking at the bulkhead...etc" referred to checking for corrosion/continuity if testing at the components showed no reading.

I didn't pressure-test yet; I found a few leaking coupler hoses (and air,) so I didn't bother. Once I know the system is thoroughly bled and not leaking, I'll pressure-test it.