TL;DR: If you’re having intermittent issues starting your Magna check out the details at this link: https://martybugs.net/articles/magna-stall.cgi
Just a quick-ish one today.
I’ve been bashing my head against an issue we’ve been having with our 2003 Mitsubishi Magna for several months, initally when you try to start it. It will fire up for about a second then the ECU kills the engine, sometimes after 4-5 attempts you can get it to start but sometimes it just outright refused.
We’ve had the RACV out a couple of times, each time they’ve diagnosed no spark and we’ve towed it back home. These engines are smoewhat notorious for eating ignition coils so that was my first thought, replaced the ignition coil (which is rather a pain in the arse since it’s inside the dizzy but shrug), no dice, took it to a mechanic at that point because I figured it was better to make it somebody else’s problem. Started flawlessly every time for them ;/ (at least it was due a service anyway) they suggested the issue might be the LPG ECU (or possibly just the suspicious fitment… the wiring is extremely shoddily done), or potentially the ignition module, but didn’t want to “throw parts at it”.
Issue cropped up again, and I did some research on the LPG ECU, turns out it was setup to start on petrol and then cut over to LPG 0.9 seconds later, which lined up suspiciously well with a “click” I was hearing from the general vicinity of the ECU when the engine cut, which lead me to believe the LPG ECU was inappropriately dropping out the fuel pump relay even when the system was switched to petrol. So after some research I found I could get a replacement (and a full wiring harness for when I get sufficiently bored to unfuck the wiring job the original installer did) for about $300, seemed like a worthwhile exercise (subsequently pulling the PCB out I found a bit of corrosion around the place so thought that was a good indication of trouble).
Replaced the LPG ECU, everything was fine… For about a week… Back to it’s old tricks again, I did notice though that the LPG ECU was indicating an O2 sensor fault, and when I measured it with a multimeter to confirm it was reading very wrong, didn’t get time to do anything further prior to heading off to Japan for a month though. When we got back it was behaving the same way it had been but at least our house sitter was able to collect us from the airport bus, next time we tried to start it though (and every time since) “she’s dead Jim”, no spark…
So this morning I put it up on stands to get a the O2 sensor to order a replacement (actually I was under the impression this engine had two O2 sensors, one for each bank and the first thing was to figure out which was connected to the LPG ECU, turns out I was wrong, there’s only one…) and disassembled enough of the interior to get to the trans tunnel bung the wiring runs through, while I was doing that I got to thinking, surely even with a screwed O2 sensor it should run, just not necessarily very well? And probably ought to throw a CEL (which it wasn’t doing consistently) to boot?
So I went back to the interwebtubes, and asked the googles (actualy DuckDuckGo) about “Magna ignition faults” (might have been some other keywords too) and started clicking through the forum links, it was there (on Whingepool of all places) that I discovered a link to this complete and utter gem https://martybugs.net/articles/magna-stall.cgi scanned through the article and thought shrug worth a try…
So I went out to the car, pulled off the lower section of the driver’s side dash, and there in all it’s glory was the connector that connects the antenna around the ignition barrel back to the BEM… Sitting, barely together, not making contact at all… “Surely not” I thought, plugged the connector in, lo and behold IT STARTED, and has started every time I’ve tried since…
In this particular case it was a bit of a team effort though, Mitsubishi had apparently decided that stringing wiring harnesses that control immobiliser functions TIGHT across gaps is a good idea, and then the cretin who installed the LPG conversion had (rather than running over the steering column like a sensible person) cable tied one of the LPG ECU harnesses to that part of the wiring loom putting it under even more stress rolleyes.
I’ve since re-routed the LPG harness and strapped the connector together with some cable ties so hopefully this is the end of this issue once and for all… (Only took about $1k in parts and mechanic bills, several busted knuckles, the odd laceration or two and a lot of facepalming to get there).
Finally THANK YOU Martin Pot for taking the time to document this exceedingly frustrating issue on your website, we were seriously considering replacing the car due to this but now we can put that off a while longer.