318i M40, doesn't like throttle on a cold start

[jimbom30cab]

1989 318i M40.

It snaps into life as soon as i turn the key on a cold start but then for a few minutes if i use the throttle it almost stalls and then immediately picks up. When warm it drives and idles perfect.

I've just had the engine out for a full service but it did the same before then.

Stuff i've done

Cam belt
New plugs
Vac pipes all checked good
New voltage regulator
Changed AFM for a known good one
Cleaned out ICV
TPS clicks as soon as the throttle opens
Dizzy cap, rotor arm and CPS all cleaned up and in perfect cond.
Timing checked spot on when we did the belt

When it's warmed up it drives perfect.

I am getting the injectors cleaned next

Any ideas most appreciated.

I'm thinking maybe the TPS is dirty inside and although I can hear it click it may not actually be making/breaking contact. The combo of the ICV still energised and the TB open maybe take the mixture out of spec and stop combustion.

Thanks

[Yeti]

whats your fuel pressure like as cold it demands more ?

[jimbom30cab]

Not sure but have a spare FPR, might swap it and see

Thanks

[broadie]

I'd check the coolant temperature sensor resistance at the ECU plug.

[jimbom30cab]

Thanks, i must do that, the sensor looks new so just assumed it would be ok. You're right though, I should check it.

[Brianmoooore]

Get the injectors rebuilt ASAP, and check the TPS more thoroughly. Check it that it is short circuit with a meter with the throttle closed, and check its adjustment. It must switch to open circuit as soon as the throttle moves off of its stop. Any appreciable throttle angle before it does will result in a flat spot.

[jimbom30cab]

Thanks guys will do all that today.

I have a spare set of injectors ready to post off to injector tune also

Thanks