[Sean's Jaguar XJS Tech Pages]
Lucas Digital P (HEI-based) Ignition Diagnosis

Last modified 2005 APR 07 04:40:08 GMT

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These are reluctor pulses (the "star" wheel in the distributor, which triggers the HEI ignition module). Note that although the amplitude (voltage peaks) differ slightly, both the 1985 (top), and 1988 (bottom) show about the same pattern.

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This is a 10ms grid of the reluctor pulse on the 1988 XJSC.

The GM HEI circuit data used in the Lucas CEI ignition amplifier. Unfortunatley, the site where the docment is requires registration in order to access the documents there - right click this link and copy it to your clipboard, then follow the link, which will end up redirecting you to the login for the site, create your account ("register", which is free, though as with any website that mandates you provide an email address, you might want to use a freemail account of some nature for this - and it MUST be a valid account because they send your initial password there). Once you have an account, log in, then PASTE the URL from the clipboard into your browser location, and you should get the PDF. Yea, ugly, but the datasheet is there, and if you want it, you'll need to jump through some loops. You might ask, why not just republish it here on my site? It is copyrighted material, and I don't feel cool about doing that without permissions.

A simple generic photo diagram showing how the GM HEI unit is installed WRT the other ignition components (not Jaguar specific).

The GM HEI Module diagram. This isn't the same type of module used in the Jaguar (this one has additional connections), but certain things should prove similar.


Sean B. Straw
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Petaluma, CA 94975-1224 USA

EMail to: Sean.Straw+Jaguar@mail.professional.org

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