Occasional Jerking

[scin]

I am experiencing a sudden and violent jerk of the engine/car sometimes when I accelerate very hard on my E30 (motronic). The revs drop suddenly by a few hundred RPM and the car jerks violently, usually at about 4500-6000 RPM during hard revs.Most things like AFM,ICV, throttle body, etc etc have been checked.Doesn't happen all the time though...Anyone got any ideas???

 

[tchdaniel]

Check ur intake rubber boot for tear.Hope that helps

 

[scin]

er, sorry ah.. what is an intake rubber boot???????

 

[chriseunos]

im having this problem as well, motronic. My mechanic say the fuel pump not working at its best. Well, i just let it be

 

[nevets]

hmmm m hvg similar problem...could it be the fuel filter as well or worst a combi of both

 

[scin]

Both my fuel pump and filters have been changed not too long ago....

 

[python_dev]

Turbo lag?

But seriously...
I had the exact same thing when I first got my car with the M40 engine...
the problem was eventually resolved from info on this forum...
M40 bad habitS.

AFM failure.
Cam wear

In my case was cam wear, didn't look like much but as soon as you got to 4500 it started jerking like it was short on fuel, no power. changed cam and tappets and it's been fine ever since.

 

[teejay]

scin,
coud be a possible injector leak or jammed, try and check the injector o-rings

as it only happens occasionally, there is a variable item - cracked intake boot may allow unmetered air to enter combustion

last but not least, the ignition cables at the ends could be loose, so a thorough check with a voltmeter should be done

good luck

 

[scin]

thanks,teejay/python...
will chek on those items

 

[drag86]

:burnout: My E28 have the same problem. After changing the fuel pump rectified the problem,make sure you replace the fuel filter too.