Hey guys. I posted about this before but couldnt find the previous thread. Basically, I came home from work one day for lunch about a month ago, got back in the truck to go back to work and it did crank over, but no start. I checked with a in line light spark plug wire and I am not getting any spark. Also not getting a check engine light either by turning the key on or by doing the ON/OFF key to get trouble codes. We checked everything and even checked the hot wires of the wiring harness to the PCM and we are getting power to the PCM but apparently nothing out. We have done the following:

Used the shop manual to check the
coil
Crank Shaft position sensor
all relays in the engine compartment

We cut out the factory power splice under the realy box and soldered everything back together,
Replaced the pickup coil inside the cap
installed a new cap and rotor
Put in a new High performance Mopar Performance PCM from Summit racing

I am really stuck on this and any further suggestions would GREATLY be appreciated.

 

Ok quick update.

Installed the new computer (PCM) today and its still just giving me the ABS BRAKE and Oil dummy lights. So I disconnected the computer and turned the truck on and to my surprise the same three lights came on. So it is acting just like the PCM isnt connected or the new pcm is dead.

I used the FAQ and tested the ASD relay once more and all terminals check good with all the readings that I should be getting. I blew out the wiring harness and tried once again to get the check engine light to come on and still nothing. I am literally at my wits end with this issue.

 

After reading through some of the other posts I have found where folks were not getting a check engine light, all of them said a new PCM corrected the issue. So I am going to assume that this PCM is dead as well and exchange it for another one through summit racing. This wont be the first or last time that I have had to go through several new electronics to find one good one.

 

Make sure the PCM is grounded. Two tan wires that hook up to the back of the right head. The exact same thing happened to me just a week ago.

 

Yeah that sure was fun troubleshooting, Sam.

 

Excellent suggestion. I did double check it just now. With Key off, 11 and 12 showed no ground. With key on I got 12.50 volts. Tried it again and still no check engine light or spark.

This proves my point though. I have proven that power is getting to the PCM by checking the ASD and the pin that supply power. And also proving that the grounds are working correctly there should be no reason why the check engine light isnt coming on.

 

Honestly, if you've verified that the PCM is physically grounded, followed the power flow chart on the schematic and verified that everything is delivering the proper volts upstream of the PCM, and still don't have a check engine light or spark, I'd say your guess is right that you might have a bad PCM.

Summit should be pretty easy to work with.

Sorry to beat that dead horse, but where were you testing the ground for the PCM at? Sam and I actually held it against bare metal just to ensure it was getting a good ground-- and that's what it wound up being.

 

I put the positive lead on my volt meter on the battery then put the negative on pins 11 and 12 on the wiring harness to verify that it was getting ground when the key was on.

I then verified based on your recommendation that the ground on the passenger head was still intact and checked it also with the voltmeter.

 

One thing I dont see in here that you havent tried since you have a distributor is to check the ignition module that is seperate from the PCM.

 

What ignition module are you refering to?