Re: The S38 is a high revving engine (archive)

I switched from stock to a Jim C chip. I find that I have better than average torque at lower RPMs, and a much smoother torque curve. But I still keep it above 2000RPM if I want any real acceleration. I think the Jim C chip was well worth it. You have to use premium either way!

Check the coolant temp sensor on the aluminum pipe above the exhaust--blue plug. It's a common failure point and source of poor running on the E30 M3. The vacuum leaks described in the other messages are definitely a concern, too. Replace the fuel filter, and check the operation of the 2 fuel pumps. A bad transfer pump could cause poor idle, poor driveability, and low power. The Bentley describes flow rate and amp draw tests for the 535i, and the M5 uses the exact same pumps.

My M3's tach does the exact same thing, but only when very cold outside. I'm thinking the SI board batteries are getting weak. Bad batteries can cause a myriad of instrument problems!!

Good Luck!
James
james_535@yahoo.com
88 M5
88 M3

You won't have much torque at 1800 rpm. I try not to run my engine at that low rpm, I prefer to keep rpms at about 2500 or higher. Although the engine will pull from 1800, it probably doesn't really like it.

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