Working on a friends 94 ranger, 2.3 L with codes 218 and 998. Chiltons manual does not even show this code. Code is for Loss of Ignition Diagnostic Monitor (IDM)/left side. What exactly is this? Can't find anything that explains the IDM.

998 means a hard fault.

Any help would be appreciated.
Ken

 

Check the coil pack to see if its windings are open circuit, or shorted. Check its electrical connector, that you have +12 VDC @ KOEO. Check the crank sensor for continuity & output when the engine is cranked. Check the ICM & let us know what you find.
Ford had an OBD-1 tutorial posted on their Owners website at one time that we could access, I'll see if I can find a link.

 

If you find a link that would be helpful.

Thanks
Ken

 

Looks like Ford/Motorcraft has taken the info down.

Here is a link, scroll down to find a nice wiring diagram for the 94 that you can probably make use of in trouble shooting. http://www.justanswer.com/car/0dvk4-...8-223-224.html

 

Have you checked the left side coil pack out & that its getting B+ at KOEO???? Make sure the ICM mounting screws are clean, unrusted, snug & making good ground connection.
This system has a dual vane crank shaft sensor, an output to the ICM for each coilpack, so make sure both sensors are outputting to the ICM, especially the left side sensor, which through the ICM triggers the left side coilpack, for which you have a DTC.

 

I'll check both. What is the ICM? What sort of output should I see? 12 VDC pulse, 5 VDC pulse? AC?

A little more info: Owner said the truck had no power and running rough. Changed out plugs and wires since my neighbor owned the truck a few years and now his brother has had it for 6 years and neither had ever been changed while they owned it.

#2 and #3 cylinder plugs looked ok for the amount of use. #1 both plugs looked as if they were not firing as hot as they should, sort of a yellow looking insulator,

#3 right side plug looked as if it had not fired in years, gap was totally bridged by gunk and was totally black. Left side was firing but looked worn.

After clearing all the codes which I did write down for future reference, truck ran ok at first but now is low on power again. When he brings it over again I will see what code have returned.

 

I'm probably gonna get flamed by the 4banger guys for calling it an ICM = Ignition Control Module, as it had several names, depending on where it was mounted under hood over the years, before finally being incorporated into the computer = PCM = Powertrain Control Module. No matter where its located, its job was the same. On the 93 & 94 2.3L, it was mounted to the side of the intake manafold & some things had to be moved/removed to get at it.
So, maybe have a read through this thread https://www.ford-trucks.com/forums/1...-224-help.html & use your inductive timing light to quickly, safely & easily check for spark on the suspect coil. Or use your multimeter to check its primary = typ 5 ohms or less & secondary = typ 12-15K ohms resistance, or compare the two coilpacks resistance values.

If that checks out ok, back probe its electrical connector to see if you have 12 volts B+ to the coilpack at KOEO. If thats ok, but you still suspect the left side coilpack, remove it & have its spark output bench tested, most autoparts stores can/will do it at no cost. All this to first narrow things down with the easier tests on the thing you have the 218 code on, as you work your way back toward the ICM & crank sensors, for which you have no trouble codes right now, so they belong lower down on your suspect list imo.

Good feedback on the plug read. Check that plugs coilpack first, as it being fouled for a long time may have damaged the coilpacks secondary winding & its spark may be weak or missing.

This engine had an electronic, distributorless, waste spark, ignition system. One coilpack is used to start the engine & after its running the icm turns on the other coilpack to fire the other set of plugs. Half of the plugs get a normal polarity spark which eminates from the spark plug center electrode to the sidewire. The other plugs get a negative polarity spark, which eminates from the sidewire to the center electrode. Companion cylinders spark plugs are paired together such that when one cylinder fires on its compression stroke, the companions plugs are fired on its exhaust stroke (waste spark). SO, we need to be sure to use the specified spark plugs & wires, that are designed to be able to take this Double work load!!!! Standard spark plugs won't last long, so we need at least double platinum, or better still, the newer finewire iridium enhanced center electrode, with platinum pad sidewire design plug, thats designed to take the double workload of the waste spark ignition system, without suffering early electrode spark gap erosion & the resultant misfire.

The plug wires also need to be designed to take the double work load of the waste spark ignition system & OEM is recommended, as they are of good quality & their resistance & capacitance will be in spec to keep the ignition system design values in tune. So, if you forgot to do it, or didn't use the specified OEM parts, make sure the plug wires end to end resistance is in spec.

All that said, a number of other things need to be checked out & the P0218 trouble code would suggest beginning with the left side coil pack, so begin there with your inductive timing light, or multimeter, as suggested above.

Maybe have another look at the right side #3 plug, to see if its fouled again.

More thoughts for consideration, maybe others will chime in too, so keep us posted on the trouble shoot.

 

Thanks. This was the info I was looking for. I will check all and pass on what I find, probably early next week. Also, I stated above that the #3 cylinder right side plug was fouled, it was actually the #4 right side. Also there were other codes but I wanted to clear all of them and run it to see what came back. I did write them down for future reference.

Thanks again.

 

Finally got a chance to look at this again. Coils checked good. Engine was only firing on #2 and #3 cyl. When I first looked at the problem a few weeks ago there were numerous codes stored but they were not really related to one another. Also the owner stated that it had an intermittent problem where it would turn over but not start. When I went to check the crank sensor, the truck would not start. Took the ICM and had it checked and it checked bad. Replaced it and the truck runs like a champ. Also the tach works again which had not worked for quite a while, and no check engine light which had been on for some time also.

Thanks for the help.
Ken

 

OK, good find, fix, feedabck & to hear all now seems well & your friend is on the road again!!!!. Ahhhh the tach not working would have been a good clue that the ICM was the root cause of his problems, as the tach gets its info to operate from the ICM!!!!

 

Yea, I think that would have been a great clue. I guess he had been driving it for quite a while with the tach inoperative and same for the CEL. He does not remember if both started at the same time or not.

I appreciate the help