Harder to get to redline

[jrwilson]

Originally Posted by boyt911sc

So when did the mechanic work on your car? Before or after Carlisle Swap Meet? BTW, whatever happened to the WUR I shipped to you?

It was before. The allen key has been sitting in there for quite awhile. I guess something made it move and jam in the hole.

I got the WUR and installed it, and it's working great. Thanks again! I'm still dealing with the harder cold start but it's not the end of the world.

[Schulisco]

Originally Posted by jrwilson

It was before. The allen key has been sitting in there for quite awhile. I guess something made it move and jam in the hole.

I got the WUR and installed it, and it's working great. Thanks again! I'm still dealing with the harder cold start but it's not the end of the world.

Bosch&Porsche recommend in the CIS workshop manual on adjusting the CIS / CO only putting the allen key in for adjustment and directly removing it again because it's weight heavily affects the mixture! See the instructions from the CIS manual:



Concerning the harder cold start - if the WUR is in spec and fits correctly to the car (check part no.!) I would check first and foremost for vacuum leaks with a smoke generator! If leaks have found and tightened check the sensor plate height as Porsche specified, in this relation also check mixture and idle afterwards.
If everything is tight and correct I would continue with checks of cold start valve & thermo time switch (don't know how early CIS car are equipped in that way) and fuel accumulator (it needs to be tight at the overflow and the diaphragm needs to move freely) and the check valve at the fuel pump. If car sits and both FA & check valve are not tight any more, the fuel pump needs much more time to (re-)pressurize the system on cold start.

Thomas

[jrwilson]

Originally Posted by Schulisco

Bosch&Porsche recommend in the CIS workshop manual on adjusting the CIS / CO only putting the allen key in for adjustment and directly removing it again because it's weight heavily affects the mixture!

Well, yes? The mechanic was sloppy.

Originally Posted by Schulisco

Concerning the harder cold start - if the WUR is in spec and fits correctly to the car (check part no.!) I would check first and foremost for vacuum leaks with a smoke generator!

Smoke tested, no leaks.

Originally Posted by Schulisco

If leaks have found and tightened check the sensor plate height as Porsche specified, in this relation also check mixture and idle afterwards.

All good.

Originally Posted by Schulisco

If everything is tight and correct I would continue with checks of cold start valve & thermo time switch

Both checked and working as expected.

Originally Posted by Schulisco

If car sits and both FA & check valve are not tight any more, the fuel pump needs much more time to (re-)pressurize the system on cold start.

Brand new fuel pump with check valve, brand new FA.

Next step is putting that helper spring in the fuel head.

[boyt911sc]

Jeremy,

I had no luck buying 4 pieces of helper springs. I bought 4 pcs. on July 5 and was scheduled for July 14 delivery. They never showed up and got refunded yesterday (July 25). My ‘78 SC started after the 4th week. And some people might need this piston helper to correct their cold start problem.

Tony

[jrwilson]

Mine arrived a couple of weeks ago, haven't had time to investigate. Cheap thing to test that for sure won't hurt either way!