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Low power, strange idle

Posted: Sat Nov 25, 2023 11:12 pm
by Flaffy1991
Hello guys.

I recently picked up an ‘86 M325i, lovey thing. Needs a bit of body work and a general tidy up but all round good car.

The car runs a bit strange though, unsure if it’s just me but it doesn’t seem like a nice smooth running engine like I’d expect.
On idle it has a weird sort of chop to it as if it’s cammed, you can hear it the best when I’m at the side of the car on the attached video, but the revs seem stable if that makes any sense, and at low revs (under around 2500-3000) it doesn’t feel like it pulls much. After that it wakes up and pulls really strong.

It’s a bit tappy but has apparently had a top end rebuild fairly recently. Could this be down to bad valve clearance or is this likely another issue.

Had a Quick Look at the cap and rotor today, they look newish and giving them a quick clean made no difference.
Also I checked the vacuum system using brake cleaner (not scientific I know but didn’t show any leaks)

Any info or advice?
Thanks.


Video of said idle:
https://youtube.com/shorts/T7rDfV_o2b4? ... QU-O7HRQ_S

Re: Low power, strange idle

Posted: Fri Jan 19, 2024 10:03 pm
by twright
Yes, the valves need adjustment. If you're lucky, that will fix your idle.

Is the exhaust smoky? I couldn't tell from the video if it was just water vapor or something more of a problem.