1988 325i Touring runs mega rich - why??

[Andyboy]

Replaced the air flow meter and the coolant temp sensor yet it still runs absolutely stinking rich - it is literally chucking petrol out the back and it runs like a camel. Throttle position switch is set okay and 'clicks' and substituting a 320i ECU made no difference. The wiring plug under the inlet manifold is odd - rather than the traditional screw twist plug it has two snap together plugs which I think is an aftermarket job. But all the wires match up and there doesn't appear to be any corrosion. The air flow meter mixture screw is wound right out and it still must be doing well over 10% C.O.
It does have the BMW dealer mod with the in line resistor to the coolant temp switch plug which was a bodge up to cure poor cold starting on some early plakky bumper E30's and E34's with the M20.

Any ideas gents?

[Andy335Touring]

Duff fuel regulator/vacuum leak ?

Has the P/O fitted the wrong injectors or may be theres an injector thats sticking open ?

Have you tried running it with out the resistor ?

[E30Mark]

Is it just running rich on idle, or at higher speeds?

Have you checked the plug gaps....

[Andyboy]

Stinking rich everywhere. Yep, taken resistor out. I reckon the way around it is to do a complete inlet manifold/injector and loom swap. Replace the whole sodding thing in one hit. It'd be quicker than pissing about for hours with a scope measuring things.

[toughguych]

Mine runs stinking rich too.
Did a cam job and changed water temp sensor and loads of other bits but it still soaks up petrol like a v12 on acid!
Any closer to figuring it out Andyboy??

[Ant]

if its stinking rich at idle, and no faults can be found, ajust the throttle stop screw a tiny bit( with car on emits tester and fully warmed up) to get the mix and HC readings within spec again

in short, the stop on the TB wears and the airflow is reduced as a result, the ICV can compensate up to a point but then the HC's creep up, idle quality suffers and juice consumption goes up.

you must alter the TPS too. ensure you get a click just as the throttle is opened.

Done correctly the end result should be a car with good CO HC and 02 readings, and rock steady 680-700 rpm idle