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Bmw m42 can not start Link ecu

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Hello everyone ,

I have problem with a bmw m42 turbo engine. I can not start the engine. I have fuel and ignition. I have double check the series of the spark pin out and the Injector pin out. I have check the fire order table and the trigger calibration. The ecu read rpm when crank.but the engine did not listen to want to start or to have fire. I work a link storm ecu. Also We use vw r8 coil. The dwell is around to 3ms at 12 V and 4.5ms at 10V. I don't known what else to check. Any idea?

Can you attach a trigger scope, map and log of cranking and that may give us some clues. Is the engine a fresh build or has it run before?

The engine is a fresh build but it work first with stock ecu for 500km and after that I put the storm. I have attach a log file which you ask. I have fuel and ignition when I crank the engine. The spark plug was wet after some try to start the engine. So I though that the problem was the timing of ignition, but I used the same trigger offset with a same motor I have builded( M42B18 bmw) with a LINK monsoon.

Attached Files

Have you tried a trigger offset changed by 360 degrees? Depending on your cam sensor signaling (polarity), perhaps you have the cams out of phase (does the stock ECU) run sequential, or is it perhaps wasted spark (and thus cam phase doesn't matter).

The engine with stock ecu have sequential ignition and injector with couple (1-3, 2-4) So it is possible something like that. I have try from -114degree to put 246degree but I have no result. No I have do ignition and injection sequential

David you are write !!! I turn it 360 more and work perfect !! Thanks you very much !!!

OK, so now you have to understand the difference between the previous engine build/ECU and this one. Was the polarity of sensor wiring the same, or is something different in the Link Configuration?

This is a real learning opportunity...

This is true. So we have two same engine with same wiring trigger. Both of them have ignition sequential. But one have sequential injection and the other with couple. The first with couple of injector working with -114 calibration degree, But the full sequential with 246. I can't find a logical explanation about that.

I suspect the other engine would work at 246 degree calibration. I'll bet that when you couple the injection, the ignition is also coupled (i.e. running wasted spark), so it fires on the other phase allowing the engine to run.

No I try to work with 246 but the engine not start!!!it is the first think I though. How is there possibility to work with sequential ignition and all of them have a waste spark time?? What else?

Hi Peter, As I suggested to you on Link webchat the other day, there are really only 3 possible explanations:

1. Coil wiring is different.

2. Firing order in ECU set different.

3. Cam tooth is in different position.

Of those, #3 is the most likely and the reason I kept asking you to do the trigger scope...

Some BMW's for instance have the cam tooth occur almost at the same time as the crank "gap", so if in one engine the cam trigger occurred just before the "reference tooth" and in the other engine just after the reference tooth then there would be a 360° offset.

Hi Adam, thanks you for your replay. the #3 is more possible but it will be strange that both of two cars working fine with OEM ecu with different to cam tooth.

With missing tooth trigger wheels, Link (and most other aftermarket ecu's I'm familiar with) use the first tooth after the gap as the reference or index tooth (this is where your offset is measured from). The BMW OEM ecu will almost certainly use some different strategy (since start up speed etc is more important to a OEM).

OK! this is interesting. Thanks you for this info Adam. There is any article between different on the principle operation of stand alone and OEM ecu?

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