overheating Coilpacks

[Greg_D]

hello all,

i am having trouble with the coilpacks on my 2003 mx5 turbo overheating at the mo.

I have recently had my engine replaced and a few days afterwards my car came spluttering to a halt on the side of the road, the coilpack closest to the bumper was actually melting and smoking (bearing in mind that i had a new clutch fitted as part of the new engine so i haven't been over 3000rpm for the last few weeks, ie granny driving) once it cooled down it started working again. the car is running a begi turbo kit and an EMB, the jumper settings are correct on the EMB and the tune isn't what i would call wonderful but it is safe.

this started to become a regular occurance, ie after a bit of a drive it would splutter, i would pull over and let it recover and carry on my way (only while i was waiting for a replacement to arrive) I have subsequently replaced both coilpacks and the one in the same position got hot again after a couple of days (not melting hot but it was starting to splutter) The plugs are iridiums and so the gap was preset out of the box so should be alright.

Any suggestions as this could be a very expensive hobby if i need to keep replacing these all the while

could it have anything to do with the 320 injectors running constantly in the no boost zone making the engine run too rich and fouling the plugs, hence making the coilpack work harder??? possibly.

Greg

[stevieturbo]

If the coils are melting, it can only be from head radiated to them ( is the turbo/manifold mounted close by ?? ) or the coil drivers are charging the coils far far far too long, and frying them fron inside out.

If the latter, there is some serious ecu related problems.

If the former, heat shielding of some sort, or use different coils and mount them elsewhere, and use longish leads.

It will not be fuel related.

[Greg_D]

it is not a radiant heat issue! and there have been no changes to the ECU in ages. Puzzler

Any other opinions!

[GreenV8S]

Greg_D said:

it is not a radiant heat issue! and there have been no changes to the ECU in ages. Puzzler

Any other opinions!

Yes but things will inevitably fail from time to time, and when you're having work done on the engine there's every excuse to cause problems. For example if the coils are earthed via the ECU it may be that the loom has got pinched and it's earthing itself when the problem occurs, or maybe the ECU has developed a hardware fault.

[ridds]

I'd just replace them first.

Are they all doing it or just one? (Or is it one unit).

[Greg_D]

i have already replaced them both and the replacement front one (the same as the original faulty unit) has started to exhibit the same problem, so it is not the pack.

Greg

[ridds]

Hmmm, perhaps change the plugs back to originals for a while and continue driving with light load.

[Greg_D]

A quick update

I have fixed the problem, Woo hoo......... it was a loose earth strap that my local greasemonkey hadn't properly tightened when he installed my new engine it was the one that attaches to the throttle housing on the front left of the engine.

note to all, if you are getting any wierd electrical problems, check your earths first.

Greg

[ridds]

It's always the simple things isn't it.

All makes sense now yet never springs to mind when you're scratching you brains. Good find.