No Spark Summary and Solution
Well it’s been a long thread to finally get to the heart of the issue. I can’t tell you how many hours I have spent reading post, checking components, running down wires and trying to decipher wiring schematics in order to resolve the No Spark issue on my ’94 VDP.
I would be completely remiss if I didn’t acknowledge all the support and suggestions received here on the JagLovers forum, what a great bunch of guys, really, thank you all. I also want to acknowledge a couple of forum guys who went above and beyond what would normally be expected to help resolve the issue. My heartfelt thanks to Grooveman and Mike Stone, and a special thanks to Mike’s brother Mark, who is not a forum member and doesn’t even own a Jag, but got involved at Mike’s request because of his expertise with wiring schematics. At my last post #184 I had really exhausted everything I could think of and was at a dead end, I really had no place else to look and I still had No Spark.
There are four major components that work together to produce spark, the CPS (Crankshaft Position Sensor, ECM (Engine Control Module), IA (Ignition Amplifier aka Ignition Module) and the IC (Ignition Coil). Although I had purchased a new coil and used but purported good replacements for the CPS, ECM & IA there was a lingering question as to the working condition of the used parts. In other words, were the used parts really in good working condition or was I just replacing one bad part with another bad part?
It was here that Grooveman sent me an email suggested that I might find someone local with a ’94 VDP that I could persuade to let me swap out each of my original components on their Jag to see which component was bad, if any. I replied to Grooveman that the thought had never crossed my mind, and while I thought it was a great idea, that was not something I would feel comfortable asking another Jag owner. You can imagine my surprise when I received an email from another forum member with a ’94 VDP offering to test my parts on his Jag if I would send them to him (he was out of state). Of course, I agreed and was extremely grateful for the offer (this had Grooveman’s fingerprints all over it). As it turns out testing each part individually and then in unison they all checked good.
After receiving my components back and installing them I still had no spark. This left me back at No Spark and out of ideas and places to look. It was then I got a call from Mike Stone and his brother Mark, they asked if I had a few minutes to run some test and of course I was delighted to hear from them and to run any test they wish. Mark had been studying the wire schematics and wanted me to pull the Ignition On relay and manually jump across 30/87 terminals in the base, in other words make the connection the relay would normally make. I did this and checked for spark at the HT tower of the coil, not only did I have spark, I had strong spark. I installed the HT lead back in the coil leaving the jumper wire in place at the relay base. Cranked the engine and SHAZAM it fired right up. BAD RELAY.
ISSUE RESOLVED: Long, long story short, it all boiled down to a BAD Ignition On RELAY. The problem was intermittent, early on I checked the relays and they checked good. As reported in this thread there was a couple of times the Jag started and ran fine for a couple of days, then just quit for no apparent reason.
Had I taken abercanadian’s (Larry) advice back at post #15 I would have saved myself and everyone else’s time. That said, I’m not a fan of replacing parts without knowing the part is bad. On the plus side I know more about my Jag and what makes it tick then ever before and made some really great friends in the process.
In closing, I can’t express my appreciation for this forum and its members enough, THANK YOU ALL.