throttle issue

[sadham]

when applying the throttle I either get no response or fully opened response.

For example I pull on the cable a small amount, the revs will be around 500rpm, pull on the cable a little bit more and it revs to red line. There's no in-between.

I am thinking the TPS but would anything else be a likely culprit?

[arrisbmw]

take the rubber boot off that leads to the throttle body, get someone else to push the pedal and watch the butterfly inside, open / close in the T/B. IT should open smoothly and progressively as the pedal is depressed.

it could be caused by jammed up or ceased accelerator cable, return spring in throttle body , or at the pedal.
it does not sound like the tps sensor more likely a mechanical issue.

[sadham]

Wouldn't of thought it would be something at the pedal end as I was pulling on the wire from where it attaches to the throttle body. Not even pulled it much at all just slightly. Even slightest movement was making the car rev all the way. Intermittent though, either no throttle and car was bogging down and dying or full throttle.

The butterfly inside is opening and closing smoothly.

[arrisbmw]

check out the idle control valve , rubber pipe to it and where it fits on the underside of the inlet manifold
for air leaks.
the idle should be 850 rpm with the butterfly closed in the T/B this is controlled by the ICV. AT idle
might need a clean.

[sadham]

Would that still be the case if the timing is off?
I was going to try and do the timing by keeping rpm at 2200 while i turn the distributor but the issue explained above just wasn't allowing it to go to 2200rpm.

[arrisbmw]

timing , what year and engine have you got. is it carb or fuel injection. ?
pre-face lift ? model

[sadham]

318i pre-facelift fuel injection m10 engine.

[pianist]

Check for air leaks around intake mani behind the TB