85 XJ6 No start, coil problem. Please Help

[dvr]

I am getting current at both + and - terminals of the coil with ign. on. I have checked and put new terminals on the 3 wires to the neg post and 2 on + side. This is a new Bosch coil. Car cranks but will not fire. Car ran 2 wks. ago so it can't be too serious. Has me stumped.

Thanks for any help. I want this car running yesterday!

Dan

 

[Deleted member 8987]

Probably the amplifier module, but, as with all electronics, you will end up spending a whole lot of money and still not run if you just throw parts at it.
Here is a place you can download an 18MB .pdf that walks you through the ignition testing.
This is the main link (at the bottom of the descriptive paragraph, it has a link to download):
https://carwiringdiagrams.net/tag/87-jaguar-xj6-wiring-diagram/

Which takes you here:
https://www.mediafire.com/?fgwfm0zvgbc

 

[dvr]

Thanks. I appreciate the reply. I am also very hesitant to just replace parts willy nilly without definitive testing. I suspect the ignition amplifier also. Would like to test it. I will start with new cap, rotor, wires, plugs. Coil is new as stated previously. This car is a rehab project.

Thanks All

 

[dvr]

Just checked the price of the ignition amplifier, $450-$550. Are you kidding me? Must have gold or platinum inside. Ha Ha.

 

[Deleted member 8987]

Yeah, I knew that. Makes one want to think about points again.
Next most common failure (and there is some argument as to module or this being "first") is the crank position sensor.
If you read the writeup, early on, big warning, don't leave the ignition on for more than 10 seconds without engine running.
That will cost you $450-$550 initially.

 

[Deleted member 8987]

BTW, first test, always, pull the coil wire out of the cap, hold it about 3/8" from the head, have someone crank it. If you don't get a consistent series of healthy "zaps", no amount of cap, rotor, wires and/or sparking plugs will make any difference to the lack of spark from the source.

 

[DrEntropy]

err... I don't mean to be critical here, but:

Car ran 2 wks. ago so it can't be too serious.

That's not much more helpful than the response... "Put the car on the 'phone and we'll <span style="font-style: italic">ask</span> it what's wrong!"

A systematic diagnostic scheme will find the errant bit. Preferred first test is the spark one TOC outlines. Determine if the iggy is putting fire to the dizzy cap. If so, rotor, cap or wires. If not, that fancy "Sparkerator Box" or coil need to be checked next.



Use a process of elimination. Is there a smell of unburnt fuel (raw gas) at the tailpipe?

<span style="font-style: italic">
EDIT: And welcome aboard! Don't be put off by my comments... We really DO want you to find the answer. It's just that from a screen to the car we don't get much visceral feedback when attacking a problem. We need the "human element" at BOTH ends.</span> :wink:

 

[jessebogan]

I have good news and bad news on the ignition... From what I can find out, new pickups (in the distributor) are not currently available. However, if the amp tests bad, open it up. Inside you will find a GM HEI ignition module. Get the number off of that, and have a chat with your friendly local auto parts store (FLAPS). They should be able to match it up, for WAAAYYYYY less than the price of a new complete module. Get genuine GM if possible. evidently they have the best dwell performance.... Still, even a cheap one should make the car work.

If I remember correctly, you can take a test light and connect it to one or the other(both, but one at a time...) of the small coil terminals, and crank the car
The test light should pulse, indicating that the pick up module is switching the box and coil. Unplug the PU wires from the amp, and test the pick up w/ an ohm meter. Should be 2200 to about 4500 ohms.

 

[dvr]

Thanks Guys. I am getting spark from the coil. Will replace cap, rotor and wires and will report back.

 

[jessebogan]

Check and see if advanced distributors makes a rotor for your car. Lots of rotor issues these days.

 

[dvr]

Just an update: New dist. cap, NGK plugs, new wires.
She started right up. Thanks for all of your input. Very much appreciated. All I need now is to replace the brake master cylinder and she'll be on the road again!

Cheers!

 

[DrEntropy]

YAY!! :thumbsup:

...now we want pictures. :wink: