Car Died Driving to Work
 

I've had my first frustrating issue with my '89 XJ6 VDP... I had a no start the other morning after it had been running great. It came down to being no spark. I followed a guide on another forum "Ten Tips for a Non-Starting Engine", and if that person is a member of this forum as well, I'd like to thank you for that awesome write-up. Anyway, I was at step two, measuring the voltage at the ignition amplifier plug. I got proper voltage but the plug was all gunked up with what i assume is old, dry, dielectric grease. I cleaned it up and sprayed it with this stuff I got from work (electrical spray cleaner/corrosion preventer/dielectric lube) and put it back together. It started right up! Only on my way to work this morning, right before I got on the freeway, it died. I squeezed that plug a little and tried it and it started up again. I drove back home and switched cars... Has anyone else had problems with this plug? Is my ignition amplifier on the way out or do they just stop working? I'd like to be able to drive it without worrying but considering its a Jag, that may never happen. Any help would be greatly appreciated.

Wash all the dielectric grease away from both male and female plugs with degreaser then clean up with contact cleaner not "dielectric lube". Make sure pins are clean and tighten up any jaws on female plugs too.

These cars depend on good connections as they are electrically controlled. Go through all sensor plugs and relays in the engine compartment and remove any dielectric grease you find ...chances are if the OP has put it in one connector, it's in them all.

If you think the amplifier is duff, not a big deal to replace it - used ones are pretty cheap.

Larry

Thanks for your response! I cleaned it out really well last night letting it sit for a bit and blasting every so often. I forgot I had a can of CRC QD Electric Cleaner, which worked pretty well. It looks nice and clean in there now. I got the amplifier best i could from the angle and it looked pretty good. I may pull it out just to make sure its nice and clean. I'll be going over the rest of the bits this weekend to make sure I don't have any other gunked up plugs as you mentioned I may. Hopefully I don't have any issues with that after this, but I guess I'll never know until I put some miles on it. I plan to drive it to work again on Friday (35 miles or so round trip) which will be a good test.

Thanks again!

Hi Civicalized,

Welcome to the XJ40 forum and congratulations on your latest Jag.

If the male pins in the ignition amplifier or harness connector are flat, rather than round, you may be able to improve the connection by using needle-nosed pliers to very carefully and very slightly twist each pin so it fits in the female socket more securely.

I don't think this is your problem, but just in case, there was a TSB about repositioning the ignition amplifier to correct certain malfunctions. On the later cars the amplifier was reoriented 90-degrees from the factory:

Intermittent Loss of Power - Reposition Ignition Amplifier

Cheers,

Don

Thanks for the TSB, I think I'll go ahead and do that this week, considering it's pretty simple and could only help. I have put probably 100 miles on it since it died and haven't had any real issues since. I had to swap out the brake master cylinder because i couldn't get the front port to do much and had really spongy brakes. I flushed the lines and it stops great now. I do have what sounds like some bushings up front that need replaced. I did the upper shock ones already, but still have some knocking, though not as bad as before. Any recommendations on bushing kits or is there much of a difference on these? For what it's worth, I'll probably replace shocks in the near future as well.

The most common causes of front end knocking are those shock absorber top bushings you've already replaced, but If you're sure you got the shock top nuts tightened all the way down until they stopped on the spacer tubes, then other suspects include the anti-roll bar bushings, the anti-roll bar links, the lower shock bushings (pressed into the control arm) and the control arm bushings. A very badly perished ball joint or outer tie rod end can also knock. Our forum sponsors like Coventry West, Welsh Enterprises, SNG Barratt and Jagbits can help you find the best quality bushings currently available - options may be limited. I would personally avoid hard polyurethane bushings since many owners who have tried them complain of a harsher ride and suspension squeaks.

Cheers,

Don

I'll look at mine again and make sure i got them tightened down all the way. It does sound like it's coming from lower on the car than when the uppers were knocking, but it is hard to tell when you're sitting inside.

On another note, what's a standard readout on these gauges? Mine's the early model cluster and while my voltage and temperature read where they should, my fuel constantly reads low (even with a full tank, sometimes it shows full, sometimes almost empty, but mostly about a third). My oil pressure is almost always at the full "8", which seems like it's high, but today I had it drop to zero a couple times for 3-4 seconds, and pick back up. Nothing changed with the motor when this happened, as far as engine idle, but that short amount of time might not make a difference. My oil and filter have about 200 miles on them, and the last oil didn't look terrible, with no shavings or sludge that I could notice. I read somewhere (I can't find it now) that these sending units are a common issue. Is the issue caused by the sending unit what i described, or do i possibly have something else going on? I'm running 10w40 in it and the temps were low 50s at the time (Boise is sort of a desert... Very cool mornings, possibility to get pretty warm when the sun comes up). I'll probably go a little thinner before winter because we have had some pretty cold winters recently, but still. Should i be worried? I still need to go through some connectors and clean the grease out of them, but my issue sounds similar to this https://www.jaguarforums.com/forum/x...ressure-52574/, So i think I'll swap out the sending unit regardless.

The fuel level sender is a very common failure point and it is relatively easy to replace if your fuel level is below about 1/4 tank. For access, remove the spare tire, jack & tools, along with any other fasteners or obstructions, and carefully pull out the carpeted trim panel at the front of the trunk/boot. The fuel level sender is about halfway up the rear face of the fuel tank, with a couple of wires connected to spade terminals. Disconnect the wires, then use a wooden dowel or brass punch and a hammer to tap the locking ring counter-clockwise until it will come free. Take care not to damage the gasket. Carefully fish the sender out of the tank - the rod is longer than you expect and there is a plastic float on the end that can get caught on baffles and such inside the tank. Reinstallation is the reverse.

The oil pressure sender is another very common failure point, and unfortunately access is difficult due to its location below the intake manifold. It is much easier to do while you have the intake manifold disconnected and pulled back from the engine, but it can be done blind with the manifold in place, using a crow's foot wrench and much patience. IIRC, the hex on the sender is SAE (inch fractional), not metric. Also, it is critical that you clean the threads in the port in the engine block thoroughly with a good solvent such as brake parts cleaner. The sender is a single-wire unit and its ground path is through the block and engine ground strap, so any oil on the threads of the sender or the port will add resistance that will cause incorrect gauge readings.

Cheers,

Don

I couldn't have asked for a more clear explanation! Thanks Don for all your help so far. It looks like I've got a nice weekend ahead of me getting some things fixed! I will keep you updated as I get these things worked out. I used to (a few years ago) not care for the XJ40 all that much but I am finding that it's a really enjoyable car.

I had a no-start situation this Saturday that left me a little annoyed. I didn't have time to mess with it then, but got to work on it yesterday. I noticed the whirr of the fuel pump was absent so I start checking relays and power to them and such, and there was no issue that I could find. I figured I'd work my way to the pump ('89 VDP, not terrible to get to the fuel pump) and test the power back there. With my wife running they key I got power once, and figured I wasn't making good contact with my multi-meter. I decided to take the pump out and bench test it, which tested good. The PO had replaced the pump six months ago so I had a feeling that would be the case, but who knows with the quality of some parts these days. I replaced the pump, mounted it back up and all, figured I'd see if there was any change. I turn the key, hear the whirr, and it started right up... I'm going to assume at this point it was a poor connection to the pump or something, but I can't be entirely sure. I'm going to spend some time driving it tomorrow and make sure the issue is resolved.

On a positive note, I found at least one of my knocks when I hit small bumps in the road. Whatever shop the previous owner took it to for the pump and filter neglected to replace the rubber piece that surrounds the filter and hold it tight. I cut a piece of rubber and put it in there which snugged it up nicely.