dzaprev

Hey guys , I have a 1979 928 Euro CSI , was running O.K. but not perfect . So I fixed several Vacuum leaks and went to adjust the Fuel/Air Mixture screws. The Mixture screw didn't seem to change anything before the I fixed vacuum leaks .Then I fixed them and I gave it a like 6 turns and now it won't start . So I do not see tach bouncing ? But I do have spark and compression (checked timing belt and it's OK) I want to start at a base setting that should get it to run and then I can work from there . Is there a spec to start out on Idle and fuel/Air screws? This is my first CSI

jpitman2

If you are talking of the 3mm allen screw just in front of the airplate housing, its a VERY sensitive adjustment! From my reading here, to get it running, turn the screw IN (clockwise) with the pump running (not cranking) until you just hear the injectors start to open, then back until they just stop. It should start then, so you have something to adjust. Take it in VERY small steps, and you have to press the key to engage the adjuster, and release pressure to get a true mixture. You should also get a set of gauges so you know the pressures are in range - Roger carries them.
jp 83 Euro S AT 57k CIS

The Forgotten On

First thing you should do is procure yourself a set of gauges and set the pressures according to the WSM.

Doing the adjustments without the gauges is a guessing game at best and an engine replacement at worst from washing the oil off of the cylinder walls and diluting the oil with gasoline.

karl ruiter

Actually, this specific adjustment does not need the pressure gauges, because he is talking about adjusting the idle mixture screw, not the CPR. What this screw controls is how far closed the air metering plate can go. What I do is back out the adjustment, and then tighten it until I see the air metering plate just start to crack open. That should get you to the point that it will start. Getting a good idle from there can be tricky without 1) making sure you control pressures are correct (like TFO suggests above), and 2) an exhaust analyzer. But assuming you are OK on 1) is is possible to do 2) by ear and seat of pants.

dzaprev

I got it ! Set the fuel mixture screw way lean and turned it a 1/4 turn at time till it idled. Then warmed it up and fine tuned it . The tach doesn't bounce are anything untill you get it to close to the running range which confused me . Running like a champ now . Thanks Karl