1994 XJ12 24 hours of lemons racecar electrical help
 

I am part of a team called Fraidy Cat Racing and we compete in 24 hours of Lemons in California. We ran 1 race last august and have been repairing our '94 XJ12 for our next race at Infineon Raceway in Sonoma. Everything has been going smoothly, but as of yesterday, we tried to start the car and it won't start. Keeping in mind that we have removed every non-essential part of the interior to turn it into a racecar, but have kept the stock instrument cluster for diagnosing simplicity. The little readout on the cluster just reads a bunch of jumbled half-letters when we turn on the power. We think that somehow we messed with the power to the cluster when we removed the turn signal, but don't know how. Any suggestions would be helpful. Below are a few pictures so you know what we are working with.

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I bet that thing moves like a scalded... cat ;). What does it weigh in at now?

Sorry I can't help with your problem.

Does the car turn over or is it dead completely?
Scott

The car is quite quick and only weighs 3400lbs with the roll cage and everything ready to race.

The car doesn't even turn over. All that we get, is a jumbled mess of letters on the dash readout when the ignition is turned to on and nothing else.

Nice looking beastie.

With all the stripping out that you did I would imagine that it is going to be 'stab in the dark' suggestions as to why it won't go.

So here is my stab 'Inertia Switch' and or a squiffed connector to the brain.

Can't offer more than that, except good luck. And post up some video of you racing when you get it going.

Yes, the inertia switch was my first guess as well - assuming (which I obviously am) that the XJ12 has one. I'm afraid I just don't know much about this car, except to say that, like the six cylinder models, the electrics can be a mess. A real rat's nest.

I'd check to see whether the switch has been tripped for whatever reason. Perhaps the non-start and the garbled VCM are coincidental. I know that the XJ6's are also especially touchy to batteries that do not have a full charge. I would also confirm that you have full starting voltage.

Best of luck!
Scott

Thanks for the help guys. I will try to reset the inertia switch tomorrow morning. Can you tell me where it is located?

I don't have any videos on my hard drive of the last race, but here is the car running two weekends ago, before we had our mystery electrical problem.

http://www.youtube.com/watch?v=hoiw9...layer_embedded

Could be anywhere on your car by now. LOL But originally behind the trim panel down by your left ankle bone.

On a RHD car it is near the right ankle bone. ;)

Car sounds sweet at least we know that it should run.

maybe if you could define what you mean by the above, and list all electrical changes since the last time the car ran, then some new eyeballs might see something significant.

there are electrical diagrams around here somewhere.

The only change that we have made to the car since it last ran was removing the the turn signal assembly on the steering column. We removed it, then began fabricating our intakes and welding up the exhaust. When we tried to start the car at the end of the day, nothing. The first thing that I am going to do today when I head over to work on the car today is locate the inertia switch, unplug all of the connectors in the dash, plug them back in, and then rewire in the indicator switch. Hopefully something is just loose somewhere and this will fix it. If not, then I'll have a long day ahead of me. Thanks for all of the help.

ummm... did you weld with gas or arc?

So, we unplugged every electrical connector we could, bought an ignition from a picknpull and put it all back together. It started up with a jump this time and since then haven't had any problems starting. We think it was the ignition switch. Anyways, thank for all your guy's help. We didn't even think of the inertia switch, but as we were locating it, we triggered it. It's good to know that it may be the cause of a problem down the road. It seems to be running well as you can see in the videos shown below that were taken as we tried to wear in the brakes a little on our street. Our one little problem that we are finding now is that there seems to be a transmission fluid leak and we think it is coming from the top of the dipstick. Is it possible that if overfilled, the fluid would come out at the top of the dipstick? It sounds so much better in person, which is why I am inviting anyone who is in the area to come to the 24 Hours of Lemons at Infineon Raceway on March 26-27th if you want. You guys can hang out with us in the pits and check out all of the mayhem that is Lemons. Rumor has it, Pandejo Racing might be bringing their XJS as well. Once again, thanks to everyone's help; it is much appreciated.
http://www.youtube.com/watch?v=7loW4CjAsJY
http://www.youtube.com/watch?v=32WcsbAUNXg
http://www.youtube.com/watch?v=KXy0M-fbh-Y

What a great offer, I would take you up on it like a shot, but you are just a bit too far away. However, when you compete at Le Mans 24hr, if your offer still stands, sing out, I'll be in your pits faster than a rat up a drain pipe. LOL

Good that you have got it running again. If it were me I'd want to be looking at removing the Inertia Switch circuitry nothing worse than a slight nudge and the car shutting down when you are in the lead. (no idea how to remove it myself)

I suppose that you do have a dead man's cut out system?

Regards your transmission fluid leak I hope one of our tech guys can help, it shouldn't be pressurizing up through the dipstick.

In your vids, have you just power washed the engine by any chance?

We will be disabling the inertia switch in the coming week, in order to ensure that we don't accidentally trigger it as you suggested. We did just wash the engine bay in order to diagnose any leaks. The only one we have is the drip of transmission fluid (which we had before) but we were just hoping that we could locate the origin location. I guess we will just have to keep searching for it.

I sounds great. Are you using the original computer or aftermarket?

I drove an '88 5.3 last month that had been dyno tuned with a Wolf 3D and the improvement was significant.

Hi Fraidy, What happened ? The 26/27th came and went and nothing from you ! We're all wanting to know how you faired. Are you racing anywhere closer to LA this year, if so I for one would love to come and see you ?.......Roger.

Sorry for the late reply, but the race went extremely well. Surprisingly we didn't have any problems at all for the entire weekend. With our Nascar pads, we were even able to outbrake most of the BMW e30s and miatas. Our suspension modifications worked amazingly well and the car was a blast to drive for the entire weekend. We ate through what we had left of our Dunlop Star Spec's and will have to get new ones before the next race. We finished in the top half of the pack (~180 cars) and got a mention of surprise from the judges of the race at the awards ceremony for somehow keeping the Jag running all weekend long. I have attached a few pictures and a video of our dyno run before the race. We ended up with only 210HP at the wheels and 320 lb-ft of torque. I have 6 hours of in car footage as well that I am combing through and soon will post a video of the highlights.

YouTube - Jaguar V12 XJ12 Lemons Dyno Run
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As for engine management, we use the stock ecu and programming. We don't have the money for an aftermarket system, and the stock one is doing just fine. We are planning on racing at Infineon again October 22-23 and that's as far South as we go. Roger, you are more than welcome to come on up for that race if you would like, but I anticipate that it will be a little too much of a drive for you.

Love the pics, and that aero package will have Jean Todt and his boys drooling;)

Thanks for the pics, even in a dismantled stage this is an eye catching car

Are you sure it was only 210?

Sounded more like 1000.