BMW M52 engine on S80, HELP!

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mefmotorsport
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BMW M52 engine on S80, HELP!

Post by mefmotorsport »

I have a customer who bought an S80 from elsewhere and I made him the loom for his turbocharged BMW 2.8 M52 engine. The engine is running fine in non sequential wasted spark mode but it wont run when sequential is selected.

The tuner doesn't seem to be too familiar with this engine (or DTA for that matter) but he suspects a cam sensor issue.

He might be right since when I was originally getting it up and running I noticed that the cam sensor (2 wire magentic) is only 12 ohms so I'm wondering if with such a low resistance the signal might be much too small for the S80 but I havn't actually had a chance to measure it with a scope.

The pink cam signal doesn't seem to appear on the oscilloscope test trace.

I notice that this engine is unusual in that it has a magnetic cam sensor but a hall effect crank sensor (usually its the other way round), and there seems to be variations on this depending on actual car and age of the M52

ie: http://www.ebay.co.uk/itm/Cam-Shaft-Sen ... OSw44BYGWB~

Maybe it would be best to fit a hall effect cam sensor?

Any comments?

Martin
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Re: BMW M52 engine on S80, HELP!

Post by Alex DTA »

Yes, the mix and match of sensors on the M52 and M54 has caught us out a couple of times.

Make sure nothing strange is ticked, like the reverse cam signal edge setting.

Then I'd throw a new VR sensor on there, it's already wired for that.
Hall Effect cam sensors do seem more reliable though.
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mefmotorsport
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Re: BMW M52 engine on S80, HELP!

Post by mefmotorsport »

Alex DTA wrote:Yes, the mix and match of sensors on the M52 and M54 has caught us out a couple of times.

Make sure nothing strange is ticked, like the reverse cam signal edge setting.

Then I'd throw a new VR sensor on there, it's already wired for that.
Hall Effect cam sensors do seem more reliable though.
Thanks, yes the VR sensor is actually new. maybe worth fitting the Hall effect version and altering the loom for him.
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Re: BMW M52 engine on S80, HELP!

Post by mefmotorsport »

they've now fitted a hall effect cam sensor and are getting a proper signal. It still wont run in sequential mode but they are trying to figure out how to set up flywheel mode 26 with the help from a data sheet supplied by Alex. It seems rather complicated and at present I dont have time to assist them!
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Re: BMW M52 engine on S80, HELP!

Post by Alex DTA »

Send them to me.
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Re: BMW M52 engine on S80, HELP!

Post by mefmotorsport »

Alex DTA wrote:Send them to me.
Ive not heard from them since I passed on the mode 26 document, if they get back on to me I'll pass them on to you Alex,

thanks,

martin
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Re: BMW M52 engine on S80, HELP!

Post by Jon K »

Martin - on these engines the only real way to do this right is use a proper hall cam sensor. The M52 generation had some weird times in the production run where they used a sensor that was more of a proximity sensor than a hall sensor.
1992 700RWHP Pump Gas BMW
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Re: BMW M52 engine on S80, HELP!

Post by mefmotorsport »

Jon K wrote:Martin - on these engines the only real way to do this right is use a proper hall cam sensor. The M52 generation had some weird times in the production run where they used a sensor that was more of a proximity sensor than a hall sensor.
Thanks Jon, I think they realised this and changed it for a hall effect one, the original cam sensor measured only 12 ohms and they were told it was called a "hybrid" sensor. I cant see a 12 ohm sensor producing a decent signal from a poxy steel blade on a camshaft !
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