Quote:
Originally Posted by aardvarkash10
The ignition amp is vulnerable to heat because its an electronic device that generates heat in its normal operation. This heat has to be bled off somehow, and so it sits on an aluminium heatsink with a heat transfer cream in between the two. This cream dries, hardens and stops doing its job allowing the amp to get too hot. Eventually its internal components fail.
I don't like guessing as Dave will tell you.
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I've only ever seen a spot of heatsink compound at the most behind an original ignition amp Ash - on any car!
More often than not, there has been none at all, relying simply on the physical contact. Normally one of my first preventive maintenance tasks on any car is to remove the ignition amp and clean up the mating surfaces then apply a bit of heat transfer paste/heatsink compound/cream.
In some cases this has even cured/revived failing ignition amps when i've started getting an odd misfire soon after taking ownership and a long run.
Either way, the old compound needs cleaning off with something non-abrasive, degreasing and drying and new stuff applied.
Sometimes on remote diagnosis such as we perform on this (and other forums) a "best guess" is the only way, usually because the person who has the problem has no real prior knowledge of the intricacies of fault finding. Very often that person has little or no technical knowledge either so much of it has to be descriptive (eg the little black box on the inner wing behind the headlamp etc) which obviously doesn't make life easy.
Guessing tends to work out expensive at times though and as we both know, very often wrong.
However, given the other evidence so far, it is pointing at the ignition amp as the best guess. I'd still like to see all the earths removed, cleaned, checked and refitted, just to eliminate them as well.
