924Board.org

[DouglasM]

So I went through everything to discover why my UK spec '80 931 was dying after about 20 seconds of running, actually didn't change anything but it miraculously started running pretty well and stayed running long enough to get to operating temperature and for me to set the ign. timing. All well, then I was able to check vacuum, very good, no leaks, then set idle around 900 was idling a bit lumpy. I started playing with the mixture only to discover the front hose had come off of my Co anylizer, I don't use it too often... Anyway, when I tried to restart, I developed a warm start problem and started playing with the mixture on the fuel dizzy and have now completely lost track of where the adjustment was before I started playing with it. so now I'm sure I'm miles out and I am still having the warm start issue, hopefully it will restart once it is cool. My question is, Is there a starting point for the mixture setting? so many turns from open to closed etc? I've counted 35 turns from open to closed.

Any help appreciated...

- D

[Paul]

From a search of Smoothie's old posts:

Miker wrote:
The adjust screw in the air meter was removed and I have replaced it (not sure if it should be tight or where it should be) and the throttle body idle screw has been played with. But the point is, is I cannot even get the car to start or idle??????

Do the initial mix screw setting... Jumper the fuel pump relay to activate the fuel pumps. Turn the mixture screw in slowly and without downward pressure that would move the air metering plate. Stop right at the point where you start to hear fuel running through the fuel distributor to the injectors. Turn the screw back out 1/2 turn - this should shut off the fuel pumps and leave you with a good initial setting that allows you to start the engine (assuming nothing else is wrong).
Finish up the procedure quickly once you hear the fuel running through to the injectors, so you don't spray too much raw fuel into the cylinders.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

[DouglasM]

You're an ace. I'll try this tomorrow...

- D

[DouglasM]

that worked a treat, just a half turn or so rich as it turned out. Now I need to solve my warm start problem... Thanks again.

[Paul]

A fix that works every time is to install a switch to run the fuel pump since the hot start problem is caused by vaporized fuel in the system.

Install a toggle switch, hook one end to circuit 30 on the back of the fuse box and the other end to the supply side of the 16 amp fuse in position 2 in the smaller fuse box. (fuel pump fuse).

Before trying to start the car when hot, flip the switch and let it run for about 15 seconds to flush the system with cold fuel. Turn off the switch and start the car. Repeat if necessary.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

[ideola]

Before you go to the trouble of doing the "hot start fix", make sure you are following the owner's manual instructions for hot starts. When the engine is hot, you must depress and hold the accelerator and THEN start cranking. Almost without fail, the car will start within 2-to-4 revolutions. I believe there have been many mis-diagnosed hot start problems because people were unaware of these instructions right in the owners manual. I didn't know it myself until 4 years after owning a 924, even though my first one came with an owner's manual. As always, RTFM!!!
_________________
erstwhile owner of just about every 924 variant ever made

[DouglasM]

Great tip Ideola, that did the trick. My 944 floods when I try to start it warm with throttle so I shyed away from attempting that. Thanks again.

- D