My 1988 244DL has the Chrysler ICU. The car won't start because there is no fire. The Bentley book tells me to first check to make sure the ICU is getting vacuum. It is.

Next to check terminal post 10 for a good ground. This is on the connector that plugs into the ICU. It's got an excellent ground with strong continuity showing on the volt/ohm meter. (I should know, I went through and spent a considerable amount of time a few days ago doing nothing but cleaning grounds.)

Then, with the ignition turned on, the book tells me to check terminal post 2 for positive battery voltage. There is actually only about 1.2v showing at this post and the same at the coil.

The book says to check all the wiring. But tracing back the wiring is a nightmare! Judging from the parts of the wiring harness that I can get to, all the wiring seems good and it looks reasonably good. I cannot see any places where there could be a fault.

Is this a common problem?

Any ideas, anyone?

 

I may not have an answer for you but since I've just recently had a similar issue in my 85, I hope to help in some way:

Power to the ICU traces back from pin 2 to terminal 15 at the coil, then to fuse 11 at the fuse panel, which is switched power from the ignition (coming in at 12).

What voltage is showing at terminal 1 at the coil?
What is showing at each pin of the hall sensor plug?
Also, does the second circuit close in the fuel pump relay? There should be an audible click when ignition on, then another click while cranking (harder to hear obviously, best to remove the cover from the relay behind glove box and observe). The second element receives a signal via the ECU from the hall sensor.

FWIW, I have successfully diagnosed and repaired my 85' LH 2.2 with a no spark issue. HOWEVER there was 12V power to the ICU pin 2 and coil 15. Mine turned out to be shorting wires (6 possible sites in total, some very well hidden, some glaringly obvious) which I presume fried the hall sensor, hopefully nothing else. My solution was to remove the harnesses and inspect them thoroughly (removing 95% of the loom), ended up replacing a few wires and spade connectors and replaced the hall sensor. It was scary at first, but actually quite a satisfying day of soldering !

 

do note, 1985 (Parc's car) is in the midst of the biodegradable wiring period. 1988 is AFTER they fixed the wire insulation formula, so no longer subject to the same level of degradation.

I might add, that plug into the Chrysler ICU is quite funky and the pins can rather easily get loosened up, you need to be very careful with it as you unplug/replug it, pulling it straight out without rocking, and using a lot of dielectric grease when you plug it back in straght.. That harness connector is unobtanium and only 1988 and maybe late 1987 cars have the improved wiring, in 1989, they switched to a bosch ignition thats completely different.

 

Thanks Pierce for the info.

I looked at that connection at the Chrysler ICU and decided that I might not want to unplug that thing. Then I saw in the Bentley book where it specifically suggests NOT to unplug it all. So you're absolutely correct. Patience is a virtue.

Anywho... I've decided that, regardless of it being a nightmare or not, I will carefully and fastidiously trace all the wiring looking for any and all faults. I'm going to start right there where the wiring to and from the ICU goes under the front of the engine and looks like it might be rubbing on the oil pan.