
greglebon wrote:Hmm.

.thats not good to hear: I'm planning on using an LC-1, too.

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I dont think it actually causes any problems, it is just apparent.

I removed mine temporarily and it made no odds to the problems.


However, regarding the dizzy problem.

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.I think I can get round that quite easily.

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I have a dizzy from an earlier 4AGE: this has 24 tooth NE and a 4 tooth G signal wheel with one sensor.

If I cut an opposing pair off this, it will function as 12-1 with the one sensor


Yeah, thats what I

(and most) people did, and it doesnt work

- it makes the 5500rpm problem worse.

Its seems anything to do with the dizzy causes problem, not the number of teeth etc, although the 25style decoder doesnt like 12-1 for sure, thats a known fault.

Your milage may vary but I wouldnt waste my time next time round, I'm wholeheartedly running for the crank sensor as I have yet to hear of anyone having problems with it.


Not wishing to sound negative but my honest advice is not to bother, i fiddle with electronics some of the time in my day job

(im a roboticist

) and although im not claiming to be an electronics guru

(im primarily a mechanical man) I have plenty of kit and friends at hand to try to narrow the problem down, and so far I've spent about

£100 in fuel and wasted easily a week solid trying to sort it, getting nowhere.

The problem was i couldnt find the problem, if that makes sense

- everything seemed to function fine, i scoped the signal on the stock dizzy as it was misfiring and still couldnt see a problem/noise etc.


Another option I have is to simply replace the internals with an optical set-up.

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Any more info on the 5500 misfire cause.

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Other than the fact that I thought it was linked to the ignitor but it isnt, and the fact that it is pretty much a hard wall of crap you run into with nasty pre-ignition noises and a backfire the size of a cannon shot.

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Its no better or worse with load, its not affected by running fresh shielded cables from the dizzy.

I have the main sections of the megasquirt mainboard and each of the daughterboards grounded seperately with 5, count it 5 10A grounds.

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Ive tried adjusting the dizzy position sensors, i tried removing the G sensors totally with a hacksaw in case they were causing noise.

I've altered the PCB and tried two types of VR conditioning circuit

- no odds.

Hence my negativity im afraid.

It seems to be that the 5500 is linked purely to the 25 style decoder, but switching to the 24s9 decoder gives misfires throughout the range instead/as well.

I ended up removing the MS entirely and refitting the stock ecu as I ran out of funds and cash, hopefully I'll be back on track in a month.

Optical could be a good way and may reduce the noise prob, but really isnt it easier to weld on a 36-1 crank wheel? I'm looking at getting one machined up that will weld straight onto the pulley, but there are bolt-ons avaiable.
