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To finalise this thread: i changed the oil, the plugs and with the help of a co meter i got it tuned correctly, starts warm and cold, no more black smoke, and runs good!
To finalise this thread: i changed the oil, the plugs and with the help of a co meter i got it tuned correctly, starts warm and cold, no more black smoke, and runs good! https://www.youtube.com/watch?v=fwK9t9GdDTQ
And now the winter starts, not the best season for driving But very happy that i was able to get the Christmas tree today! Cheers everybody!
that is cool - you don’t see a 928 carrying a Christmas tree everyday!!
To finalise this thread: i changed the oil, the plugs and with the help of a co meter i got it tuned correctly, starts warm and cold, no more black smoke, and runs good! https://www.youtube.com/watch?v=fwK9t9GdDTQ
And now the winter starts, not the best season for driving But very happy that i was able to get the Christmas tree today! Cheers everybody!
Hello Arie. Well done. I used the same CO device to tune my 928. So I can see that you have set it to 1.9 which is indeed good. Specs are between 1.5 and 2.5 .
Nice pic with the Xmas tree :-)
Happy Xmas already and hope to hear from you more !
I will post some more pictures and data from my 928S because I did not manage to have my engine properly runnning...still some hesitation during acceleration...I just need to figure out how I can correctly check my vacuum
Thanks Gerrit, i whish you also a Happy Xmas I will keep an eye on your posts, might have said this before but for me the trick to check vacuum was to take of the airfilter housing take a pretty though peace of plastic (a zipbag) and put on a huge hose clamp (bought for the occasion) around the air intake:
And then put a rubber hose and blew as hard as i could into the intake manifold:
I found 2 areas that where leaking air righ away! Also the connection between the plastic and the the rubber into the manifold was leaking...Might do the trick for you?
In the workshop , they are a port to control vacuum , near break booster , it's a rubber cross with a plug in one port .
Value 450 to 530 mbar .
Hi Allan, nice to hear from you again :-)
The setup @ my brake booster is a bit different. I am missing the 2nd little blue check valve. What's the purpose of this little blue check valve ?
Please note that I do not have cruise control which requires an extra port.
Here is my current setup : Large check valve on my brakebooster T-piece with one end going to the HVAC, a 2nd one going to the Brakebooster and a 3rd one to the vacuum reservoir.
Thanks Gerrit, i whish you also a Happy Xmas I will keep an eye on your posts, might have said this before but for me the trick to check vacuum was to take of the airfilter housing take a pretty though peace of plastic (a zipbag) and put on a huge hose clamp (bought for the occasion) around the air intake:
And then put a rubber hose and blew as hard as i could into the intake manifold:
I found 2 areas that where leaking air righ away! Also the connection between the plastic and the the rubber into the manifold was leaking...Might do the trick for you?
Check the deceleration valve for the bad idle ...
It must close ( the 2 big ports ) until 630 mbar vacuum .
Clean inside with break cleaner bomb .
Allan,
If both ports remain open all the time, what would be the effect ?
I currently blocked off the vacuum hose on the decelaration valve because my idle remained too high after revving.
This is now solved, but should I perhaps block the 2 ports also when my deceleration valve is not working ? Thus actually remove the valve and put 2 caps on the ports ?
Yes Gerrit .
To test , you can put 2 plugs on ports .
At normal vacuum ( idle near to 480 to 550 mbar ) , the decel valve must not be open .
If it's open , this like a leak and it's difficult or impossible to have a good idle ( too high ) with the screw !
The engin vacuum is to low at idle with this open ...
The decel valve must be open only before 630mbar of vacuum .
To adjust the decel valve , try the procedure .
The 2nd little blue check valve is a one way vacuum .
It's important for the vacuum tank to keep the vacuum .
Yes Gerrit .
To test , you can put 2 plugs on ports .
At normal vacuum ( idle near to 480 to 550 mbar ) , the decel valve must not be open .
If it's open , this like a leak and it's difficult or impossible to have a good idle ( too high ) with the screw !
The engin vacuum is to low at idle with this open ...
The decel valve must be open only before 630mbar of vacuum .
To adjust the decel valve , try the procedure .
I have a permanent vacuum gauge at the WUR inlet.
This is measuring 500mbar at idle when engine is cold...and after warming up it is about 550mbar.
When manually pulling the throttle cable till about 3000 rpm, the vacuum decreases to 200mbar . Is this normal?
Strangely enough, my idle is steady @ 800rpm when I block the vacuum port on the décélération valve.
Also, when I tested the vacuum port on my décélération valve with a vacuum hand pump , it held vacuum till 700mbar.
So this means that vacuum side of valve is Ok. But does not necessary mean that the 2 ports are free.
11-23-2020, 03:27 PM
But very happy that i was able to get the Christmas tree today! Cheers everybody! 
