Hi there,

I had a problem with my mileage. It was low (13mpg) and I had black smoke at the exhaust, very rich mixture. My car is a 242 TURBO. I checked the whole elctrical system for Constant Idle Speed and for the fuel injection, I checked the fuel pressure and the oxygene sensor system. Everything works fine. It turns out, that the mixture was adjusted too rich by the former owner to get an idle. With leaner mixture the car won't idle anymore. I adjusted the air flow sensor plate and so I now have a poor idle with leaner mixture. The idle is poor, because the CIS can't produce a constant idle. There are always overshoots. The movement of the sensorplate is ok. No resistance and a free fall back with one or two bounces. I removed one fuel injector and jumped the fuel pump. The spray pattern of this guy could be a little bit better, but it should be ok. By lifting the air flow sensor plate, I believe, the fuel injector opens a little late. The behavior of the engine is the following. When I lift the accelerator pedal (CIS active) the rpm come down and drop at 1500 rpm immediately below 1000rpm. The CIS then work against and so it produces a big overshoot. This procedure happens again and again. Sometimes the CIS can get 900rpm.

Is it now possible, that the filters in the fuel injectors are somehow clogged, so that the injector will be closed too early? Are there any other effects possible? I must decide, whether to change the injectors or not.

Thanks guys for your help!

Olaf.

242 Turbo, 1984, 221kmiles