E30 M44: fuel, spark, no start. Very odd symptoms

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mcspike
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Posts: 156
Joined: Thu Jan 02, 2014 11:00 pm
Location: Mid-Wales

Post Thu May 12, 2016 5:49 pm

This is my last gasp at getting the engine running before I break the car! It's a fucking nightmare! Let me explain..

This is the 2nd M44 i've had in the car in the last two months. Fuck knows what happened with the first but here is the current state of things.

Fuel pressure is fine (haven't had it pressure tested but the system ran the previous engine) plugs get wet on cranking

Has a very strong spark from a relatively new COP setup. (100% set up correctly and proven working)

Cylinders 1, 2 and 4 compression tested to about 170 PSI and cylinder 3 got up to about 200 after a short delay, possibly one revolution? (mechanic said this was very odd)

On cranking of the engine it will fire(sputter) on all cylinders for maybe one or two revolutions before dying(still cranking but wheezes and stops firing). More often than not after cranking there will be a release of pressure back into the intake and after enough cranking fuel will spray out of the MAF from the pressure release.


My local garage are quite clueless, as am I. I've done all the work on the car myself so can answer any questions about it.

Any thoughts? I'll be in the market for an E36 soon as this is supposed to be my daily. Please don't make me do it :D
Ryan
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Brianmoooore
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Joined: Mon Jan 10, 2005 11:00 pm

Post Thu May 12, 2016 7:28 pm

During the development of the 6 pot m5x series of engines, the crank pulley trigger wheel was changed, and using the wrong one throws the timing way out.
I'm not familiar enough with the M4x series of engines to know if a similar thing happened with their trigger wheels, but if it did, could yours have the wrong one?
If this was in my workshop, I'd rig up a simple propane spud pipe system, and see it it runs on that, which would tell you if the ignition system and basic engine 'pump' is OK.