My 86 XJ6 won't restart after shutting down from a nice run. It will run great for hours but after shutting down, It won't start again. It will only crank. After 1 1/2 to 2 hour wait, it restarts beautifully. I replaced many items including the ignition amplifier module, BUT I DID NOT CHANGE THE CONDENSER. Is that important?

 

OOPS, its a 6 cylinder, MY BAD regarding the resistor pack, I need more coffee, thought I was in the XJS section.

NOPE.

I always remove and discard that thing whenever a new to me V12 darkens the garage door. They are/were a noise suppressor, and are OLD now and leak to earth, reeking all sorts of havoc.

Less weight, more speed, whoopee.

Hard to start HOT, check and clean 3 times, the EFI resistor pack multi pin connector, sorts 98% of this issue.

 

Thanks Grant. I really appreciate your response. Concerning the EFI resister pack being responsible for the hot start problem --- Help me to get my head around this - it seems like the there's a component within the ignition system that needs to cool down after a nice run. Does the resister pack multi pin connecter act up like this? Regards, Dave

 

David,

Not aware of a resistor pack on the 6cyl????, BUT, Doug is the guru, and when his coffee count is up a tad, he will slide by and answer that one.

Most common that I have dealt with are:

Module getting too hot and not dissipating its heat via the paste and base plate. Feel that amp, and judge if its too hot. It will get warm at idle quite quickly, so judgement is the key. HOT to the touch, not good.
Ign Coil is getting tired and old. Run the engine for a few minutes, feel the coil. If its about the same as the surroundings, OK, if its HOT, that is not good, and new coil is needed.

 

If you've confirmed (have you?) that the no-start situation is due to "no spark" then the injector ballast won't have any bearing on the problem....as it doesn't play any role in the ignition system.

Otherwise, yes, clean the connections at the ballast. Gotta cover all the bases. A problem with the ballast would cause issues with operation of the injectors.

My experience, which mirrors Grant's, is that the ignition coil and ignition module are by far the most common culprits in "only when hot" running or starting problems.

As for the condenser, remove it and see what happens. I run my V12 without one. Never tried doing the same on my 6-cylinder Series III

Over the years there have been a few reports of elderly fuel pumps overheating and refusing to pump. Plausible; it's an electric motor, after all.

Cheers
DD

 

Only one cup of coffee is my ration. But,. strong!!! Two spoons of Nestle's classic in a mug.

Learning. Heat and electronics do not get along. resistance means volts become heat,
On these as in others., a hot amp and/or coil usually mean lousy running or none at all.

The ballast and the condenser are "hold overs" from the days of points in the distributor. many just eliminate them. As Doug points out.

The condenser is a noise suppressor.. At times, static in the radio. No worse.

The heat paste is essential.

Carl.

 

Hi David,
Probably a combination of things.
If the engine runs fine for hours, then heat alone may not be the only cause.
Heat soak at rest is more of a flag as an overheated coil or ignition amplifier will shut the engine down during service.
There is an injector resistor pack in the 6 cylinder car. Front right hand inner wheel arch. The connectors point down, so moisture from above doesn't collect, however, road dirt and other splashes can rise up. A clean of this connection won't go astray as an intermittent connection is not much fun.





Also check the wiring harnesses at the rear right hand side of the engine. Older and brittle wiring can be in play here. I ended up fitting new wiring harnesses.




The starter relay may be suspect? On the firewall the squarish red block "Pektron" Again check and clean connection.


When were the injectors themselves last checked / cleaned. Leaking / clogged injectors dribble fuel into cylinders at rest. Half an hour later you go to start the engine but won't fire because one or more cylinders is over fueled via a cylinder slowly filling with petrol
Just a couple of things to add to your list.
Cheers,

Nigel

 

FTR, what others are calling a 'resistor pack' (as pictured above) is known as a "Power Resistor" by Jaguar and a "injector ballast" by me . We're all tolking about the same thing.

Cheers
DD

 

You say tomarto, i say tomaito??

 

SleekJag12,
thank you for the prompt explanation regarding emtpy relay shell, one less mystery to worry about.

I’m told the car was originally from the Chicago area which explains the corrosion issues. I have checked the engine block ground strap which is good.

I‘m not certain I’ve located two square connectors on the frame below the fake relay, a black one and white one,(PI1 and PI61) you describe and will check them this morning. I’ve undone and cleaned every body ground I can find, two beneath relays in the front, left and right. Two on firewall in the engine bay, left and right, and others under the rear seat and in the trunk. I’ve also removed both fuse boxe panels on the inner fenders to check for corrosion under the fuses and all looked good.

I’m not sure I know what the king relays are but based on your description, I think they are square tan colored 4 pin relays that are in the five locations you mention. I have already pulled them all and they all test good. Before I learned how to test relays I used the horn relay location to check them and they all worked the horn.