This is my first Jag and it was something of an impulse buy (this happens to me way too often). A v12 has always sounded really cool and so I was excited to pick the car up for a pretty decent price. I was told that it would run just great - it had "bad gas" from sitting for too long. Well, that was probably true (although I did burn all the gas I drained in my mower) but that wasn't the only issue it had.
I wound up putting in a new ECU along the way and was able to get it running but it wouldn't pass smog - I live in California and anything newer than 1975 has to pass emissions. Getting anyone to smog it is actually a bit of a trick - they like to look at it with a stupid expression and shrug. I had it at a place where they spent quite a bit of time on it and told me it had an intake leak. I hadn't thought it did, but ripped the top end apart and replaced a bunch of gaskets anyway.
After I got it back together, I couldn't get it to run worth a d*** and by this time I was sick of not knowing what the ECU thought was happening. Proper fueling was definitely the problem but I was going nuts trying to figure out why since I couldn't find anything else wrong. I'd looked at MS in the past (I also have a 1980 Porsche 928 which also uses a variety of the older Bosch fuel injection) and decided that I was going to take the plunge.
I'd done enough reading to know that it was NOT advised to install MS on an engine that wasn't running correctly but basically I was at the point that I didn't really care any more - I'd developed an almost maniacal hatred of the Lucas ECU by then. I built the kit (I'm a computer engineer by trade and know enough about electronics to be dangerous) and made sure it worked by using a preassembled stim unit before installing it. Got everything in and wired up the MS unit using the original ECU wiring, which is what another guy had done (macaddict). Went to fire it up and...
...it didn't work very well, but was better results than I'd had with the Lucas ECU. Next step was to wire straight up to the injectors and see what I got. Once I stopped using any of the stock wiring it worked beautifully. Had to do a bit of tweaking to the fuel settings to get it going but it is now running better than I've ever heard it.
I'm using PWM with the stock low impedance injectors, seems to work quite well. I'm still messing with my settings so I don't have an msq that I'm happy enough with to post but I will do so as soon as I think it is "good enough".
One of the awful components in the Jag engine is the idle air valve - it is a mechanically controlled thermostatic device that is truly awful. I've got two of them and they both fail in different ways so for now I'm acting as my own extra air valve (this means jamming a screwdriver in the hose to bypass the thing until the engine warms up). Just grabbed a Bosch valve off an older Volvo that looks like it will work, going to try that in the next couple of days.
I wound up cutting out several miles worth of wire that runs from the engine back to the original ECU location and have the MS unit mounted in the glove box area. The PO had destroyed the box by putting in a CD changer that didn't work so once I tore that out I had a bunch of unused space, plus the door makes a really nice access panel. I also removed a bunch of wiring under the hood when I took out the stock resistor pack - makes for a much cleaner install.
I've also got an Innovate wideband sensor installed on one bank and the engine is running really, really clean now. A bit rich at idle, rich at WOT and right around stoich everywhere else. Not that I spend a lot of time sniffing the exhaust but it "smells clean" - no longer that nasty smell of lots of unburned fuel. I just picked up a pass to take it and see if it passes smog - as long as I can get past the visual I'm confident I'll be OK. The sniffer test holds no worries.
There is absolutely no way that I could have done this without the various posts on the MS boards and a couple of the Jag boards. Those that have gone before did all the hard work and I would have to dig up a bunch of names to thank the people that deserve it. If you're one of them - thanks.
It's been a lot of fun and the great thing is that there's still more to do. I'll be updating my post with more information and an MSQ in the next few days.