grandpas_car
Member
Long time reader, first time posting. I am getting to the point where I am feeling clueless on my project and desperately need some ideas/advice.
The quick backstory:
I am working on a bone stock 1989 Chrysler Fifth Avenue with a 318 which back in March started suffering ignition problems. The spark was intermittently falling out and long story short I got pissed off when the first reman spark control module I bought was no good out of the box, and the second one actually made the car run even worse than the original SCM, so I decided to make the conversion to Mopar's electronic ignition. I didn't want to have issues with state inspections so my goal was to first try and convert the ignition system only, while leaving the SCM connected to handle controlling all the original emissions junk, and even the feedback carburetor. Since Mopar doesn't offer the electronic ignition kit anymore, I bought mine from Proform P/N 440-426. This kit included a new distributor, ignition control module, connector pigtail, and a ballast resistor. I have a true Chrysler 1989 service manual for reference, so looking into the wiring schematics made me realize it is actually quite simple on this car. All I did was snag my 12 volts for the ICM from the dark blue key on 12V source that is the primary feed for a bunch of other things on that car, I cut the black wire which originally went from the SCM to the negative side of the coil and connected it directly to the ICM, and then I cut the two pickup wires and spliced them into the ICM. This car never had a ballast resistor so this is all the wiring I had to do. I called Proform just to verify that I can run their ICM without the ballast resistor ands they quickly said yes no problem. I bolted the ICM to the firewall and a ground strap behind one of the bolts, fired the engine up and the car started right away. Did some adjusting on the timing and it wasn't long before the car was running great. The intermittent spark dropping out problem was now gone! On top of that, the SCM was still controlling everything it used to, even the feedback fuel metering in the carburetor. This was my main worry at the time with doing the conversion. Anyhow, fast forward 4.5 months...
The other day the key was left on and drained the battery. Keep in mind that the car has run great without a single hiccup up until this point. Well, after charging the battery, the car wont start! The engine was cranking over fine but wouldn't hit a lick. Put a spark tester inline and quickly realized I had no spark. I pulled out a test light and checked the coil for voltage. With the key on, the test light was lit on the positive side of the coil and the negative side, as usual, but the test light would not flash while on the negative terminal and cranking the engine. That told me the coil was not being triggered. I got a meter and tested the voltage on the coil. 11.75V key on, 10.5V cranking. I pulled the negative wire off the coil and disconnected the coil wire from the distibutor. With a test lead on the negative side of the coil and the coil wire held close to a ground, I smacked my test lead against a solid ground and this fired the coil with a nice blue spark and a big gap. Coil is good. I started thinking about the pickup even though they dont give much problems. Pickup measures 400 ohms, and generates 280-320 mV AC voltage while cranking. I tested this at the two pin connector at the distributor, and the 4 pin connector on the ICM. My measurements had the same values. I tested voltage to the ICM. 11.7V key on, 10.45 cranking. The ground strap connection for the ICM measures 0.0-0.1 ohms and 350mV drop under load while cranking. Okay, obviously the ICM had given up, right? So i go to the local parts house and buy a Standard branded 4 pin ICM to replace the orange one from Proform. The coil still wont produce any spark! Could the new ICM have an issue straight out of the box? Stranger things have happened. I swap it out at the local parts house and install a new one on the car and sure as the world, still no spark! At this point, I am puzzled, because this is a really simple and straight forward system. I find it hard to believe that all those modules are no good, so just for kicks I swap the coil for another known good one. No spark. I used a free distributor with a known good pickup, plugged it in and spun the shaft by hand. No spark. I swap the coil wire for a new one I had handy. No spark. I started to wonder if maybe there was an issue with the connection from the ICM to the coil negative, but it rings fine with a meter and read 0 ohms. At this point I have run out of ideas and figure I better retrace my footsteps, so I go back to square one and go through it all again and check everything. Every single bit checks out and the stage is set for the coil to fire but it just wont fire at all while cranking! I have tried everything normal, and everything abnormal that I can think of and I just cannot seem to figure out what is going on. I am at my wits end and really need some help and ideas. Has anyone encountered this before? Can anyone think of something I am missing or something else to check? I am absolutely clueless at this point. Any help will be appreciated!
The quick backstory:
I am working on a bone stock 1989 Chrysler Fifth Avenue with a 318 which back in March started suffering ignition problems. The spark was intermittently falling out and long story short I got pissed off when the first reman spark control module I bought was no good out of the box, and the second one actually made the car run even worse than the original SCM, so I decided to make the conversion to Mopar's electronic ignition. I didn't want to have issues with state inspections so my goal was to first try and convert the ignition system only, while leaving the SCM connected to handle controlling all the original emissions junk, and even the feedback carburetor. Since Mopar doesn't offer the electronic ignition kit anymore, I bought mine from Proform P/N 440-426. This kit included a new distributor, ignition control module, connector pigtail, and a ballast resistor. I have a true Chrysler 1989 service manual for reference, so looking into the wiring schematics made me realize it is actually quite simple on this car. All I did was snag my 12 volts for the ICM from the dark blue key on 12V source that is the primary feed for a bunch of other things on that car, I cut the black wire which originally went from the SCM to the negative side of the coil and connected it directly to the ICM, and then I cut the two pickup wires and spliced them into the ICM. This car never had a ballast resistor so this is all the wiring I had to do. I called Proform just to verify that I can run their ICM without the ballast resistor ands they quickly said yes no problem. I bolted the ICM to the firewall and a ground strap behind one of the bolts, fired the engine up and the car started right away. Did some adjusting on the timing and it wasn't long before the car was running great. The intermittent spark dropping out problem was now gone! On top of that, the SCM was still controlling everything it used to, even the feedback fuel metering in the carburetor. This was my main worry at the time with doing the conversion. Anyhow, fast forward 4.5 months...
The other day the key was left on and drained the battery. Keep in mind that the car has run great without a single hiccup up until this point. Well, after charging the battery, the car wont start! The engine was cranking over fine but wouldn't hit a lick. Put a spark tester inline and quickly realized I had no spark. I pulled out a test light and checked the coil for voltage. With the key on, the test light was lit on the positive side of the coil and the negative side, as usual, but the test light would not flash while on the negative terminal and cranking the engine. That told me the coil was not being triggered. I got a meter and tested the voltage on the coil. 11.75V key on, 10.5V cranking. I pulled the negative wire off the coil and disconnected the coil wire from the distibutor. With a test lead on the negative side of the coil and the coil wire held close to a ground, I smacked my test lead against a solid ground and this fired the coil with a nice blue spark and a big gap. Coil is good. I started thinking about the pickup even though they dont give much problems. Pickup measures 400 ohms, and generates 280-320 mV AC voltage while cranking. I tested this at the two pin connector at the distributor, and the 4 pin connector on the ICM. My measurements had the same values. I tested voltage to the ICM. 11.7V key on, 10.45 cranking. The ground strap connection for the ICM measures 0.0-0.1 ohms and 350mV drop under load while cranking. Okay, obviously the ICM had given up, right? So i go to the local parts house and buy a Standard branded 4 pin ICM to replace the orange one from Proform. The coil still wont produce any spark! Could the new ICM have an issue straight out of the box? Stranger things have happened. I swap it out at the local parts house and install a new one on the car and sure as the world, still no spark! At this point, I am puzzled, because this is a really simple and straight forward system. I find it hard to believe that all those modules are no good, so just for kicks I swap the coil for another known good one. No spark. I used a free distributor with a known good pickup, plugged it in and spun the shaft by hand. No spark. I swap the coil wire for a new one I had handy. No spark. I started to wonder if maybe there was an issue with the connection from the ICM to the coil negative, but it rings fine with a meter and read 0 ohms. At this point I have run out of ideas and figure I better retrace my footsteps, so I go back to square one and go through it all again and check everything. Every single bit checks out and the stage is set for the coil to fire but it just wont fire at all while cranking! I have tried everything normal, and everything abnormal that I can think of and I just cannot seem to figure out what is going on. I am at my wits end and really need some help and ideas. Has anyone encountered this before? Can anyone think of something I am missing or something else to check? I am absolutely clueless at this point. Any help will be appreciated!