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Satyr of the Midwest
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My Ford schematics show no resistor between the coil (-) terminal and the tachometer.

I think I ran into a similar conundrum. IIRC, they "doubled-up" that tan/yellow wire, so that one lead could go back to the PCM, and the other to the remote-mount ignition control module. Where that splice is for the tach, I don't remember exactly, but it exists. In the schematic for the later setup (CCD), there's a single coil (-) line off the ignition module, and it's split between the coil and the tachometer. Wish I took more pictures when I did mine. :cry

EDIT: Hang on, I found some!!! :chili: I'll post as soon as I resize 'em.

EDIT 2: The first is a "before" pic, the second, "after". Note that I only modified the lines going to the 22kΩ 0.5W resistor, not the resistor and diode for the lines in the lower part of the pic (those are for the a/c clutch).
 

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By the time I got the sheath of the resistor setup, and I am looking at the exact same one you show, I had torn the wires apart. Screw up on my part. Look below to see what I was referring to. My TFI is distributor mount. I have two tan/yellow wires, one goes to the tfi plug, the other to the negative of the coil, then on the other side of the 22k ohm split, I have a yellow tan wire going to the ECU, and a white/red dash wire going to a difference plug, but I presume it goes to the instrument cluster (tach).
 

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Satyr of the Midwest
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Yeah, that line going from pin 4 on the PCM to the suppression resistor should be clipped at the resistor and then routed directly to the ignition module connector for the IDM signal. :thumbup

I dunno why they show two resistors in that harness, though. :scratchhe
 

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Thanks, Sig for this post

Ah, gotcha. No biggie. :thumbup

In that case, I'd start looking for a faulty PIP. There's a diagnostic procedure...umm....somewhere around here or in the Haynes manual. :toothless

Honestly, the best diagnostic I've found for a bad PIP is to watch the tachometer on the dashboard. If there's no PIP, there's no tach signal. No tach signal, no tachometer reading during cranking.

EDIT: I was thinking of DTC 211. DOH! The definition for 212 is "Loss of IDM input to EEC or SPOUT circuit grounded." In that case, of course check for a grounded spOUT first, and then check out the TSB in Steve83's SuperMotors.net page regarding this condition. In essence, the shielding around the ignition harness likes to cut into the wiring sometimes. That's one important item to check. Another is the connection between the IDM line (pin 4? on the PCM) and the ignition control module. An open or faulty connection here can trip that code as well. I don't have my Ford tech service CD handy right now, but there are other things to check.

You tried both a black ignition module (one for, say, a 1994-5 Mustang GT) and a gray one, with no change? Did you clear the DTCs after changing modules?

After I get my code 332 fixed, I will begin testing for my 212 code. I promise that I wont buy any parts until I test it :toothless
 

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Premium Member
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3,991 Posts
I get this same code aswell but I'm not having any ignition problems or no starts or drivability issues.. It happens well the check engine light comes on when while I'm driving about 10-15mins into driving.
The Ignition Diagnostic Monitor (IDM) signal is a diagnostic signal for the PCM to to verify a coil firing for each PIP signal. If an erratic or missing IDM signal is received, a Diagnostic Trouble Code (DTC 212) is set.

An occasional IDM signal may not affect drivability, but can still throw a trouble code. As SigEpBlue has stated, check for an intermittent ground on the spOUT and/or IDM circuit. Also, ensure that you have the correct Ignition Control Module (ICM) and it is wired correctly to the PCM.
 

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Yes.

IDM is a feedback signal generated by the ignition system and is monitored at pin #4 of the PCM. Its purpose is to diagnose missed ignition primary pulses at the time the ECM commands the Spout signal to fire the coil. Since it is used solely for diagnostic purposes, if this circuit is not operating properly, it will not affect vehicle driveability.
The IDM (Tach) Signal is coming from the negative terminal of the ignition coil and is reduced by a resistor to make it usable before it is sent to PCM Terminal 4. Again, an erratic or missing IDM (Tach) signal may cause a Diagnostic Trouble Code (DTC 212).
 

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Using the search I'm digging up all this info and trying to absorb it.

I have a 94/95 5.8 with crank no start. Ign coil isn't firing. About to get a new ICM for it which from what I can tell needs the black ICM.

I noticed a resistor on the neg of the ign coil...should it be there? If my 94/95 needs the black ICM why is the resistor there?


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Super Moderator
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30,636 Posts
Yo Txfirerescue,
Here is the Radio Ignition Noise or Static Suppression Capacitor that Festus mentioned on a MSD Coil in a 94 by sewiv



Item Part Number Description
1 12029 Coil and Bracket Assembly
2 40904-S36 Screw
3 18801 Capacitor Assembly — Radio Ignition Interference Suppression
4 9D930 Wiring Assembly
5 — Screw (Part of 12029)
6 18832 Capacitor Assembly
7 — Existing Nut (Part of 12029)
...

Do you have the factory anti-theft system?
.
Part 1 -How to Troubleshoot a No Start (Ford 4.9L, 5.0L, 5.8L).


Yo @Festus,
Please Vote once a day for us @ http://top4x4sites.com/cgi-bin/arp/rankem.cgi?id=dsotmoon
Vote again the next day after at least 24 hours have elapsed because the programming has a built-in clock. So if you voted @ 12:00 noon today, vote tomorrow @ 12:01 PM or slightly later & so on... Hard to remenber, so I write the time down each day.
 

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Yes I believe I do have the factory anti-theft or maybe not . lol I'm not sure. It's the 94 EB. If I do have it I don't think I've ever activated it. Nothing has been removed from the vehicle.

And that picture is exactly what I'm talking about


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Yo Txfirerescue,
Here is the Radio Ignition Noise or Static Suppression Capacitor that Festus mentioned on a MSD Coil in a 94 by sewiv



ItemPart NumberDescription
112029Coil and Bracket Assembly
240904-S36Screw
318801Capacitor Assembly — Radio Ignition Interference Suppression
49D930Wiring Assembly
5—Screw (Part of 12029)
618832Capacitor Assembly
7—Existing Nut (Part of 12029)
...

Do you have the factory anti-theft

.

Miesk, you were asking about my factory anti-theft?




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