E30 Zone

I have a manual 1990 325i which has poor throttle response when cold. It takes about 10 minutes to warm up to perform properly. To get off the mark you have to get the revs quite high otherwise it will almost stall. It can be quite frustrating on the road when going through things like busy T intersections.

Can anyone give any suggestions on why this might be happening?

Thanks [/b]

Welcome to the Zone! Could be inlet manifold gasket leaks (try spraying WD40 or similar around it with the engine idling; if it briefly raises the idle speed, then you have a leak), or split hoses around the throttle body. Also check the blue temperature sensor.

Thanks for the help, but no luck

If it takes ten minutes to warm up, the water thermostat should be replaced. After that, remove the throttle body, check that the stop for the butterfly doesn't show signs of being adjusted, check the electrical operation of the throttle position switch and its adjustment, and the condition of a rubber bung blanking off a small nipple almost touching the TPS.
Remove the injectors and invest £66 having them properly reconditioned. (See our traders' section.) This investment will quickly be repaid in terms of MPG and BHP.
Check all rubber hoses associated with the inlet side of the engine for cracks and splits, and renew as necessary.
Report back when all the above is done, and if there is still a problem, we can start looking for a real fault, as opposed to the normal maintenance/servicing stuff above.