Dead X. Codes included.

[Naasau]

Not sure if this is the right place to post this thread or not, but here goes. My engine is half-dead and though I pulled the codes and looked up the definitions (posted below), I have no idea what to do next.

Okay, so my X was running oddly off and on, with the check engine light flashing about once every few weeks, and she was leaking oil pretty badly from the valve cover seals. I took them off, cleaned everything up, and put her back together, she then started running terribly whenever the engine was under load and the exhaust smelled badly of fuel, so I assumed that not all cylinders were firing, and since the plugs are less than 2 years old, and the cables about 4, I replaced the coil pack, which didn't fix anything. Got a code puller and retrieved this:

212 - c - Loss of ignition diagnostic monitor signal/ SPROUT circuit grounded
232 - c - (Trucks Only): Electronic Distributorless Ignition System (EDIS) Coil 1, 2, 3, or 4 circuit fault

To me that means some kind of computer signal failure of some sort? Does anyone have any ideas on how to go about tracking down / fixing this problem?

 

[MrShorty]

I'm not real good with those codes, but here's what I can say:

CM 212 -> TACH/SPOUT fault. TACH signal is generated by the CKP (CranKshaft Position) senosr, which goes to the ICM (Ignition Control Module) which then sends it on to the PCM (Powertrain Control Module). I suspect the symptoms you described are caused by some fault in this sequence. I'd probably start by checking the wiring between the CKP and the ICM, the ICM and the PCM. Make sure the ICM has good power and ground. The CKP is a basic hall effect sensor and can be tested with an AC voltmeter or frequency counter.

 

[Naasau]

Thanks for the response, but let's pretend that I'm a complete idiot for the moment (shouldn't be too hard). How should I go about testing the wiring harnesses from CKP to ICM and ICM to PCM? and where might the latter two be found? (I'm assuming that the CKP is somewhere on the front of the block by the crankshaft)

As a side note, I do have a factory service manual, but finding the info that I need is challenging, so if anyone knows where this info is in that thing, referencing a schematic/diagram/page # is fine by me.

 

[MrShorty]

You are correct, CKP will be at the front of the engine near the crankshaft (Usually most easily located from underneath).

ICM on my '92 is located n front of the battery next to the radiator. I'm pretty sure it will be the same for your '93.

PCM on my '92 is located in front of the passenger door, below the glove box, behind the kick panel. Again, your '93 should be the same.

When I want to test wiring harnesses, I usually start with a wiring diagram, identify the appropriate pins on the ICM and PCM, then use a DVOM to test for continuity in the appropriate circuits.

I'm not at all familiar with the factory manual(s), so I can't help you find a wiring diagram or pinpoint test. I generally use the wiring diagrams in Chiltons and do ok. Do the factory manuals have separate volumes for "general mechanical", "emmisions, performance, and driveability", "transmission and transfer case", and so on? Or do the factory manuals come with everything in one? If you could find an "emissions, performance, and driveability" section (or whatever Ford/Helm calls it), that will include all of your computer diagnostic information, including detailed "circuit pinpoint tests" for each code. If you have access to that kind of information, I'd locate the pinpoint test for a CM 212 and see what the manuel suggests is the best approach to diagnosis (they will usually include wiring diagrams for the appropriate circuits in the pinpoint test).

 

[Naasau]

One more stupid question before I break out the voltmeter, what is a DVOM?

 

[5.0B2]

Digital Volt Ohm Meter

 

[Naasau]

Might have found something.

Interesting progression, I noticed that my tach showed nothing, even when the engine was idling normally. So I talked my wife into coming outside and sitting in the drivers seat while I fiddled with the various connection points and cables, looking for weak connections or cracks inside the wires, and I found it at the connection point where the wires go into the Coil Pack harness from the EI (ignition control) module. When flexed in one direction, the tach needle came right up and showed my normal idle (about 740rpm) and when pushed another, the needle dropped to 0 and the engine died right out.

I'll post the diagrams that I found in the Helm's Factory Service Manual, however, the diagnostic directions are to be found in the 1993 Powertrain Control / Ignition Diagnosis Manual, which has to be purchased separately. Bah.

So tomorrow I might just tear that wiring harness apart and see if I can fix the connections inside it, unless anyone has another option. If that doesn't work, then it will be off to the junk yard to pull one and see if it is in any better condition.

 

[Naasau]

Oh, and some diagrams that might be handy:

 

[Naasau]

Not sure if this is legal...

So, Here's some excerpts from Helms:


















Let's hope they don't find me

 

[Naasau]

I have huge scans of those pages, so if anyone needs to see them in more detail, just ask.

 

[Naasau]

I still can't get this fixed!

Okay, so I've been pulling and replacing wires, trying to hunt down this damned problem, and though there has been some improvement (it is intermittent again) I just can't seem to find everything. Anyone have experience with this, or a magical solution?

 

[Naasau]

So, I am sick of driving my other car, while my Beast sits in the driveway like some kind of suburban sidewalk art. Is it possible that the EI module is having some sort of systems error that is throwing the codes as opposed to a broken wire somewhere?

 

[MrShorty]

Absolutely, the ICM could be at fault. I generally like to eliminate the cheaper fixes (like repairing a broken wire) before the more expensive. If you feel that you have adequately checked the wiring, the next step would be to check the CKP and the ICM. As noted above the CKP is a simple Hall effect sensor and can be tested with an AC voltmeter/frequency counter. I'm not familiar with testing the ICM (aka EI module), but a proper manual (like the powertrain control/ignition diagnosis referenced in post 7) should have the testing procedure. You might see if the Denver library system has a good manual (Mitchell or Motor are the ones I usually see in public libraries).

 

[Naasau]

I just realized that I never updated this thread. So here goes, I pulled a complete wiring harness and replacement ICM from a junkyard '93 X, and then proceeded to clean every connection and re-wrap the new harness with massive amounts of electrical tape. I then swapped out the entire harness and the ICM module, as mine looked really beat, and Voi-la! Smooth running Beast!

She still idles rough every now and then for a few seconds... not sure what's up, but if the light pops then I'll run a test. I have a feeling that she's got bad O2 sensors now, since she was pushing a whole lotta raw fuel out of the tailpipe when she was running poorly. So I'll get new ones swapped in when funds allow.

 

[Naasau]

Well, this evil issue came back with a vengeance. I ended up making a new thread about it on RMFTC, more to help me organize my thoughts than for anything else. A better walk through of my issues and troubleshooting steps and (hopefully) final solution to my problem is over there.

http://www.rmftc.com/forums/showthread.php?t=7287

Thank you guys as well, as I referenced these posts a lot as well when attacking this problem again. And MrShorty, you were right, it was a wiring issue, just not where I expected it to be.