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BoiseShark BoiseShark is offline
1979 5sp 928 project
 
Join Date: Apr 2012
Location: Boise Idaho
Posts: 199
Garage
need help with CIS

Ok, so I can get my 928 to idle durring warm-up and once the idle speed drops down after about 5 minutes or so, the thing starts to run rough until it eventually dies.

I cannot give it gas at all or it makes it worse. I apply slight pressure to the gas pedal and the thing spits and coughs and will die if I don't let off the pedal. (it's actually little backfires I think)

I put a pressure tester on the system and found the pressure to be around 80 psi and the control pressure without vacuum to be about 4.5 bar. (which is a little high..should be around 3.8....once again...i think)

One funny thing i noticed by pulling an injector to watch spray is that when I first start to push down on the plunger (I hope you know what that is...i don't know the correct term for it. The metal sensor plate under the air cleaner) i get gas through the injector but the farther i press the plunger down...the thinner the gas gets until it eventually shuts off completely. I don't think this is normal and would explain maybe why i push the gas pedal down and it dies...it might actually be shutting off the flow of gas.

I need help with this if anyone has any adeas.
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1979 928 5sp project
1984 928S 5sp black on black
Old 04-21-2012, 03:02 PM
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