![]() |
|
|
|
|
![]() |
|
LinkBack | Thread Tools | Rate Thread |
1979 5sp 928 project
|
Question on initial settings for a/f and idle...Does anyone have any tips '79 CIS
I have my car running now, but I can't seem to get it right and unfortunately i'm on a budget. I'd love just to take this down to a Porsche mechanic and say "here you go", but I don't have the money.
I know where the initial position for the the a/f mixture should be with the fuel pump jumpered I should just start to hear it whistle and then back it off until it quiets down. How many turnes should the idle mixture screw be turned out initially? I have heard two, but just wanting to make sure. The two adjustments seem to have an effect on each other and I need to know roughly where they should both start out at. Thanks for your help
__________________
1979 928 5sp project 1984 928S 5sp black on black |
||
![]() |
|
Moderator
|
The only way to really get it right is to have a wideband O2 sensor or some other way to get the A/F before the Cat.. CIS run a little rich on idle but you need to get as close to 14.7 A/F mixture at around 3K RPMs. I made the mistake at running my idle at 14.7 when it was leaning out at higher rpms. This destroyed my cat as well as my tailpipe tip.
__________________
1981 Porsche 928 "Euro" Auto Gunsmoke Metallic Flat - Black Interior 1983 Porsche 928S "US" Auto Light Bronze (Copper) Metallic - Brown Interior **SOLD** ![]() |
||
![]() |
|
Registered
|
The number of turns will vary. Just make sure it is turned to lean then turn to rich (CW) until you hear fuel going through the injectors. This method works on a nonrunning engine. There is another setting technique for a running engine.
The reason the total turns will vary is due to the allowable variation in the control pressure. Dennis
__________________
Dennis |
||
![]() |
|