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Plugs/DI Posted by Ari [Email]  (#2847) [Profile/Gallery]
(more from Ari) on Wed, 2 Feb 2005 06:17:56
In Reply to: Ignition cutting out, Anthony, Tue, 1 Feb 2005 12:11:23 Members do not see ads below this line. - Help Keep This Site Online - Signup |
The driving conditions you describe are fairly high boost, low RPM - the hill part being the key.
When the cylinder pressure is high, like during high boost, it is much harder for a spark to jump. Sparks like low pressure, not high pressure. So the first thought that I have is that you're getting no spark.
The first place to look is the plugs. Too big a spark plug gap makes it harder for the spark to jump. Make sure the plugs are the exact right NGKs, gapped per the manual (usually just a hair under 1mm). If that's OK, I'd start to suspect the DI. Electricity always takes the easiest path, and sparks are no exception. If it's hard for the spark to jump in the cylinder, it may find an easier path internal to the DI. This especially true if the DI coils are leaking. And once a spark jumps internally, it creates a carbon path to make it easier the next time.
While you've got the DI off to inspect the plugs, look for burn marks on the top of the plugs, a sign that the little spring connecting the coil and plug isn't making contact. Look for oil on the TOP of the plug, where it might be leaking out of the DI.
IF the plugs look fine, and are gapped properly, flip the DI over. There is a plastic cover held on with about 8 small torx screws. Remove the screws, and pull the cover up and off. You'll see the circuit board and coils. Hold it up to a very bright light - you should be able to see the oil level inside - not easy, but it's possible. Each coil should be at least 90% full. Any coil leaking, and replace the DI. Depending on the year of DI, the circuit board may be visible, or it may be just a solid block of potted epoxy. Either way, look for burn marks.
A weak DI may pass the visual test just fine. Sometimes a bad one will be visible. It doesn't cost anything to try. When assembling it, make sure you get the little springs between the coil tops and spark plug boots in properly. But I'd be suspecting the DI.
posted by 192.249....
, Wed, 2 Feb 2005 06:17:56 <-- Viewing This Message, Wed, 2 Feb 2005 07:28:51
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