My jaguar xj6 has recently started dying again, i suspected the fuel filter/ pump/ or the rotor ca and wires. All checked out to be fine, with the exception of my filter, which is a custom before pump unit and will be changed out today. I have noticed that the emissions pump has begun to whine and creak rather noisily and im curious if this could cause any of them symptoms which i described in the title. if not here is a run down of the problem

runs fine at start, after running on the free way for roughly 20-30 minuets it begins to run rough at idle while at a stop light and finally dies when gas is applied or left to idle long enough.

Thank you again,

 

Each time this has happens, I would like to note, after letting cool it starts back up just fine. Perhaps... the ignition coil ? im quite puzzled

 

A common culprit in the dies hot, restarts when cool syndrome is the module inside the ignition amplifier, GM part number 10482820 or AC Delco D1906....about $50. This is a common item and available under many brand names/vendors....about $25 or so. Easy to replace but you need some tiny sockets to open up the amplifier case.

Ignition coils often follow the same pattern. I personally have had good luck with the Lucas DLB170 coil on the Ser III 4.2 but any 12v coil with about 1.0 ohm resistance should work. The ballast, if you have one, can be tossed away....or kept...at your discretion.

The air injection pump would not cause this.

Cheers
DD

 

Doug, turned out to be the Coil again. Have you had any problems or luck with the Accel "super street" coils? Ive run through about 4 of these thus far, no idea why they cook so bad...

Do you recommend the Lucas DLB170 over any other "performance" coil.

Module also was replace long ago, no problem with that thoe. And just so im sure, the emissions pump is basically useless in regards to engine performance ?

 

I've never tried the Accel coil. If I had gone thru 4 of them in anyhting less than 30-40 years, though, I'd be sorely tempted to try another type of coil. There's either a quality or compatability problem, I reckon.

The Lucas DLB170 worked well on my Ser III and a few others that I know of and is only about $45 so that's why I recommend it. An added bonus in a couple cases, at least, has been a slightly smoother idle..although I have no good explanation for that. The '170 is actually a V12 coil but that's neither here nor there.


Cheers
DD

 

As far as the air injection pump goes there would have to be some very, very odd failure to cause the problem you've described. And such a failure would have to be with the control circuit of the diverter valve and not the pump itself. Frankly, I'd have to let my imagination run a little wild to dream up a air injection failure scenario that would fit your symptoms :-)


Cheers
DD