BMW 3-Series E46 (1998 - 2005) - 02 2.0 diesel - fuel timing question

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Wed 15 Apr 2009 21:07
02 2.0 diesel - fuel timing question - paulc924
I am repairing/rebuilding an engine for a friend which has ingested a metal swirl flap. I was about to check the piston/valve clearances on a dry build when something occurred to me. The crankshaft has a position sensor but I can't see one for the camshaft. How does the ecu know that it should be injecting at the end of a compression stroke TDC for a particular cylinder rather than the exhaust/inlet TDC? Sorry if this is a bit long winded but how do I know it will not be 1 crank turn out of sequence? Regards.

Edited by Pugugly on 15/04/2009 at 23:09

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Wed 15 Apr 2009 22:18
02 2000 Fuel Timing - Number_Cruncher
Is it a petrol engine?

If so, it doesn't really matter when the fuel is injected. Thinking back, there was Bosch K Jetronic which injected continuously, and carburetors, which of course, had no timing function at all.

There have been sequential petrol injection cars for a long time (late 80's or so), but particularly at higher engine speeds, it doesn't really make a lot of difference.

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Wed 15 Apr 2009 23:02
02 2000 Fuel Timing - paulc924
Sorry, diesel. This ingestion of a metal flap causing a lot of damage is a common problem which seems to be not acknowledged by BMW. Regards.
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Wed 15 Apr 2009 23:09
02 2000 Fuel Timing - Pugugly
Tweaked the subject line to reflect the above.
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Wed 15 Apr 2009 23:35
02 2000 Fuel Timing - Number_Cruncher
There are ways that the engine could run without a cam sensor, but it would be unusual.

What the ECU could do, during the starting cycle, is as 1 and 4 come up on compression is to fire no 1 injector. There's a 50 / 50 chance it's right, and if so, the crank will accelerate, and the ECU can detect that, firing no 3 next. If there's no crank acceleration, 180 degrees later, no.2 will be fired, and away the engine goes, with the ECU keeping count - the ECU knows the firing order, and knows where the crank is.

However, I would be much surprised if there is no cam sensor.
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