1985 325e M20B27 with the i head swapped on it, 5spd manual
This is my friends car that was running horribly and he wanted me to fix it before he sells it as I have an oscilloscope and a knack for finding these hard problems. So after two days scoping and verifying sensors, pathways and logic I fixed the rough running problem. THe next day I went to drive it to verify everything was good, I started it up which took 2-3 tries once it finally started I rev'd it to clear it out to about 4k, it returned to idle just fine nice and smooth, I let it sit for another minute or so then started backing out of the garage.
Once on the street I gave it a good rev (5.5k) to see if it felt fine, clutch was in and I had the gearshift in 1st. As the rev's peaked I heard a pop and the car lurched forward but didn't stall the engine. That's when the vibration started, I drove it in a short loop around my neighborhood to see what just happened and these are the symptoms. 1) RPM dependant vibration in any gear and neutral clutch in or out doesn't change anything, 2) rowing gears is much stiffer now and it doesn't like going into 3rd (grinds) unless I double clutch it, the engine seems to be running just fine and is as strong as it was before this happened.
So I returned it to my garage and called up my friend feeling sick to my stomach that I just hurt his baby. My first thought is clutch. But the vibration in neutral with or without clutch in has me scratching my head. Has anyone seen this before? Trying to make it right for him.
Last edited by Sledgehammer1; 05-09-2022 at 02:12 PM.
Look under it. Maybe just a mount or something easy
The fact that you had the clutch in but the car lurched forwards is a bit weird. I've replaced the transmission rubber mounts, guibo, and driveshaft at different times all because of vibration issues, but none of that correlates to it vibrating in neutral. Flywheel issues? 5500 is a lot of revs for engines as old as these things are getting. RPM dependent vibration in neutral sure sounds like some part of the rotating assembly is not happy.
1989 BMW 325i Coupe
1989 Suburban 4x4
2014 Ram 1500 4x4
1945 Willys MB Jeep
1959 Triumph TR3A
So I had too many projects occupying my garage to want to deal with this so I had my buddy who I bought it from do it at his shop. Here's the list:
Screenshot 2022-08-15 084706.jpg
This is my best friend from highschool who I do a lot of work on his cars on the side so I just agreed to do some springs and struts on his truck for this. Which was super nice.
Annnd then I reupholstered the seats.
IMG_8134.jpgIMG_8159.jpg
Your friend obviously knows what he is doing. Fixes the engine, front and back - quite impressive!
. You are lucky to have a friend that knows cars and can fix them and gives you a good deal.
Thanks I would've done it if I didn't have a land cruiser engine torn down for rebuild in my garage haha
For the sake of closure I figured I should drop this link since it closes the chapter on this fun little nugget. It will be missed.
https://www.bimmerforums.com/forum/s...0i-Touring-S52
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