Lumpy idle and more

Need technical Q/A then you're in the right place

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Smellit
E30 Zone Regular
E30 Zone Regular
Posts: 280
Joined: Sat Jun 02, 2012 11:00 pm
Location: Daaarset (Poole Dorset)

Post Sat Jun 16, 2012 11:20 am

Ive been away from the E30 zone a long time but have got fed up with newer cars so convinced the wife and bought a 320i 1987 more door (have child now so made sense).

Its done 116000 miles and has full bmw service history.

A few questions i could do with some enlightenment on.

1)its lumpy, almost misfiring on idle and has a hesitation when you stab the throttle down, got a coolant temp sensor, sparkplugs and throotle position sensor on the way so hope its one of these. I have check for a vaccume leak and found nothing.

2) it knocks over bumps at the front but these is no play in anything but will be changing the anti-rollbar bushes as a little split, previous owner said its the top mounts? could this be?

3) gearstick is floppy but goes in all gears fine, is this just a matter of changing all the linkage?

4) sometimes when at low revs on light throttle the car starts to shake violently forward and back and was thinking the doughnut on the prop but also think it might be to do with the rough idle, maybe a missfire?

5) the brake pedal is long, have adjusted shoes at the back which has helped alot but still halfway down the pedal?

I know im asking alot but to be honest it drives lovely compaird to new fluffy cars :)
Andyboy
Alpina Colada
Posts: 12577
Joined: Mon Sep 11, 2006 11:00 pm
Location: Notts

Post Sat Jun 16, 2012 12:46 pm

Idle; you need to look at everything. Check the plugs and leads for KV's, the state of the cap and rotor arm, mixture, valve clearances, TPS etc etc.

Knock; could be shagged top mounts although they last a long time.

Gearshift; you need to replace the linkage joints, a real fun job. You'll need to unbolt the crossmember and lower the back of the box down to make it easier. The minimum is the front knuckle joint but to do it all, this joint, the rubber bush at the front of the alloy gearlever mount where it pivots on the back of the gearbox, the white plastic cup where the gearlever fits in and a new selector shaft oil seal.

No.4, who knows? Almost certainly related to the idle issue.

Long brake pedal. Remove the under dash tray under the column, and disconnect the glovebox straps so the glovebox drops right down. Slacken the 17mm locknuts on the brake linkage cross bar, and turn the bar so the brake pedal starts to raise up. Do it 20mm (at the pedal) at a time. Lock the locknuts and try it. It works every time and cures a long pedal.
Smellit
E30 Zone Regular
E30 Zone Regular
Posts: 280
Joined: Sat Jun 02, 2012 11:00 pm
Location: Daaarset (Poole Dorset)

Post Mon Jun 18, 2012 9:14 pm

nice one, have sorted the brake pedal now. Have changed the blue sensor, the tps, plugs, leads and dizzy but still lumpy. Will be getting it on the gas analyser this week but could the valve clearences cause this much of a lumpy idle? Knocking at the front is still baffling me as change a few things there but to no avail? May just change the lot.