Knock Sensors?

[jbuttenshaw]

i have the e36 m42 with knock sensors, when i run the e30 computer in it its fine but when i run the e36 computer it seems to lose power around 5500rpm and never really pulls again after.  I have a performance chip in it but it does the same even with the e30 chip in.  You reckon it could be knock sensors, we have fully cleaned and resoldered any possible dry joints in the computer, i figure if it runs the engine there is nothing wrong with the computer? thanks

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[bmwman91]

Which intake manifold are you using?  If you are using the E30 one on the E36 M42 then there's your problem.  The E36 ECU is tuned for the dual-stage manifold, and FWIW is more conservative up top (the E36 manifold does not flow as well up there, and the ECU is tuned for this).

I think it unlikely that it is knock sensors, unless you can hear some misfiring/knock.  I'd say that it is because the E30 ECU is tuned a little more agressively up top that you see such varied results, with either manifold.

[jbuttenshaw]

i am using the e36 manifold, thought of that but the e30 chip works better with the e36 manifold. i thought i did hear it ping a bit when i had it WOT up a hill.  I'm gonna try some high octane fuel and some octane boost to see if its the grade of fuel, if that fails i have no idea, i'm considering stand alone anyway.