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So I’ve been having some drivability issues when the truck is put under load. Basically, if the throttle is more than halfway down, or when shifting from 1st to 2nd, it’ll buck, bog down, and sometimes die. I’ve posted before trying to point me in the right direction. But now I’m desperate.
I’ve run the codes on it and gotten a 332 and a 212. Both are in CM
Ive got a brand new GRAY ICM (yes I have a distributor mounted ICM, so please don’t tell me I need a black one), SPOUT is intact, not corroded, the PIP sensor is brand new, and as far as I can tell, nothing is broken and no wires touching anywhere.
for the 332, new EGR valve, even though I didn’t need it, new EGR position sensor, and new vacuum hoses. I followed the vacuum diagram, and I believe it’s all correct.
I followed the lines from the TAD/TAB solenoids, and two go back over to the ACV. When those two lines are disconnected, no change to engine rpm or idle pattern, and I don’t feel any vacuum on them.
The EGR valve is not stuck, but it is not opening either.
Am I missing something?
Other than listed above, new fuel pump, new fuel filter, new ECM, and new spark plugs since the problem arose.
I was thinking about it last night, and the only difference between the old owner ( did not have the issue) and me (currently having the issue) is I started putting power steering fluid in the damn thing. It has a horrible leak, and I have to fill it every couple of days. That’s the only thing I’ve changed in between the previous owner not having any issues, to me having the issue.
I have no clue where to go from here, so any help is appreciated.
TAD and TAB are for the air pump system, not EGR. If you are sure you have manifold vacuum at the EGR solenoid, and the line from the EGR solenoid to the EGR is good, then the solenoid must be bad.
I just worked on a truck last week with 332 code. The problem is the PO had pulled the upper intake to replace the injectors, and he pinched the red hose to the EGR solenoid in between the upper and lower intakes.
Code 212 on your truck is not caused by the wrong ICM. The gray push-start version is what you need. Installing the wrong black ICM will not trigger code 212 either. 1993 and earlier F-series gas engine trucks use a buffer resistor (22K ohm) tied to the negative side of the coil to provide the Ignition Diagnostic Monitor (ICM) signal to the computer.
Typical failure on this vintage truck is an open circuit, bad IDM resistor, bad solder joint in that circuit.
So I pulled the entire wiring harness to which all of the mentioned systems were attached to. I have to repair a few things anyway, and it’s easier to have it out of the truck. But back to the point. What resistor. The only resistor I see is one that’s about 6 inches long, says IN4003 27ohm 5w. Two black /w yellow tracer wires go in from the engine side, and two black and one black /w yellow tracer comes out of the ecm side. Is it that one?
This Post: https://www.ford-trucks.com/forums/1...l#post17551171 has a photo and link to another article about that IDM resistor. The 27 ohm resistor may be for the tachometer circuit. I have never seen a 27 ohm IDM resistor.
This photo shows the IDM resistor in a bundle of wires closer to the master cylinder:
Perhaps yours is further up or downstream of the 27 ohm resistor you pictured.
The other thing to do is ohm between PCM Pin 4 and the negative terminal of the coil. Do this key off and I suggest to disconnect the PCM. If you do not get a reading in the 22K ohm range you know you are on the right track.
I got to looking, and I found the resistor in a black sleeve. The resistor itself still has the resistance, but it was broken, and making no connection. I’ll be replacing that, and let you know if it fixes it.
So I replaced the resistor, and I can now read the codes from the computer. Wasn’t getting anything before hand. Now, I have the same 332, (EGR valve opening not detected) and I’ve now got 311 (thermactor air system inoperative), 411 (cannot control rpms during KEOR low rpm check), and 538 (insufficient rpm change during KOER dynamic response test). It did sounds like crap during the test.
I am not getting Vacuum from the ACV to the TAD and TAB solenoids. Where do I even start?
Your other codes are engine running, get your KOEO codes cleared first, then you can check KOEO codes, or it will lead you down the wrong bunny hole.
Test your coffee/tomato can reservoir, on passenger fender(my check valve inside can went bad): apply vacuum with a gauged pump to the nipple for the black line (leave the red open). If it builds up vacuum & holds, the reservoir is good.
