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Multi Discharge Ignition Systems

32godzilla

By 32godzilla,
in Engines & Forced Induction

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32godzilla Proficient

32godzilla

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Posted

I have the Ultra MDI fitted to my car (was on it when I purchased). From the very start I've had ignition problems, first with the standard coil packs (which were quickly replaced with Splitfires) as well as spark plugs.

In the 18 months I've had the car I've probably gone through over 10 sets of spark plugs and just recently a set of Iridium's only lasted 10 days! Most of the time I've been using BCPR6EY-11 gapped to 0.8mm. Everything's fine for a couple of weeks then the car starts misfiring / spluttering. I'm thinking the extra voltage / current from the MDI is killing my spark plugs but I'm not 100% sure. I got a 2nd hand coil pack wiring loom (in bad condition) to bypass the MDI but it makes the car even worse with brand new plugs. I've tried colder plugs, and gapped a couple of sets to 0.7mm but no joy. I'm thinking a new loom from Nissan might solve my issues but at $300ish it's a gamble.

The engine is stock running a Power FC, runs 1.1 bar of boost on standard R34 GTR turbos. Pic of MDI units below, any advice would be appreciated.

mdi.jpg

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R31Nismoid Grand Master

R31Nismoid

Posted
Posted

Coil pack looms are $150 from Nissan, not $300.

I purchased one when i was doing my motor install 18 months ago.

When did these MDI things go in exactly (in that 18month period).

And what was happening when the splitfires were in there? They should have been fine, so its sounding like something other than coilpacks to be honest... so going to the MDI would not have fixed it.

32godzilla Proficient

32godzilla

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Posted

Thanks for the responses guys - firstly it plays up all the time (once the spark plugs have given up) but only over about 5,000rpm and at full boost, light throttle is fine. I rang Nissan last week for a price on the coil pack loom and it was definately over $200, can't remember exactly. The MDI was in the car when I bought it - to be honest I can't see a need for it being there as the engine is only stock and not running huge numbers.

I think I might just take a chance and buy the wiring loom and take the MDI's out of the car. Maybe as Brad said the ignitor is stuffed as well??

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