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On the home straight now, goodwork! Not sure about the cold setting, but mine was severely down on power at 60 psi hot. And dont rely on stationary running temp being truly hot - drive it at least around the block to make sure its hot right through, then check pressure. Mine is great at 75 system, 45 hot control, gets 11l/100km on a cruise. If it starts cold, and really hot power is OK, pressures should be OK. Then fine tune with a wide band O2 sensor stuffed up the exhaust and a meter - Innovate, or a good garage. https://www.innovatemotorsports.com/.../mtxl_plus.php
jp 83 Euro S AT 57k
So could it be that since my hot control pressure is about 4,1 bar , it will decrease the performance of my 928?
When trying to accelerate, it poorly accelerates, even my kickdown is not working properly.
I also noticed that acceleration is better when engine is cold..
When my hot control was 60psi(4.1B) I could npot get much over 30kph - hot control that high makes it run VERY lean, so no power. Read the CIS manual - high control pressure stops the fuel delivery piston in the centre of the distributor from rising and exposing paths to the injectors to allow more fuel. Have you checked WUR for blocked - inlet screen first, then outlet hole?
jp 83 Euro S AT 57k
When my hot control was 60psi(4.1B) I could npot get much over 30kph - hot control that high makes it run VERY lean, so no power. Read the CIS manual - high control pressure stops the fuel delivery piston in the centre of the distributor from rising and exposing paths to the injectors to allow more fuel. Have you checked WUR for blocked - inlet screen first, then outlet hole?
jp 83 Euro S AT 57k
Makes sense what you are telling. But I could reach 100kph with 4.1bar, it is just that acceleration is slow. I just have troubles to reach the correct
mixture.
Turning the CO screw 1/4 turn CCW(more lean) until my CO is about 2,5% will stall the engine and prevent it from starting cold.
Turning the CO screw 1/4 turn CW (more rich) will make engine smoother run, but then my CO is way too high : about 12%
Inlet screen of WUR has been cleaned since this was my coldstart issue from the beginning.
Now it will start, but hot run is not good : as if I lack power
So perhaps I first must see how I can lower hot control pressure ? I can tamper my WUR again by driving pen further in to lower pressure...
What would you advise me to do?
From my reading the Mixture adjustment is MUCH more sensitive than moving 1/4 turn !!!! Try going CCW from high CO in 1/16 of a turn at a time. Insert the allen key in the adjuster head, make a mark on something aligned with the handle so you can judge how far you move it. If you mark where handle points at 12% CO, and 2.5%CO, then move to halfway between, check CO. If still high, move CCW halfway to to 2.5%; if too low, move halfway CW back towards high, check CO. This is a binary search, homing in on what you want. When CO looks good test drive it. Hot control is too high - have you moved the pin in the WUR? If you can get hot control down near 3B you will need to readjust here.
jp 83 Euro S AT 57k
From my reading the Mixture adjustment is MUCH more sensitive than moving 1/4 turn !!!! Try going CCW from high CO in 1/16 of a turn at a time. Insert the allen key in the adjuster head, make a mark on something aligned with the handle so you can judge how far you move it. If you mark where handle points at 12% CO, and 2.5%CO, then move to halfway between, check CO. If still high, move CCW halfway to to 2.5%; if too low, move halfway CW back towards high, check CO. This is a binary search, homing in on what you want. When CO looks good test drive it. Hot control is too high - have you moved the pin in the WUR? If you can get hot control down near 3B you will need to readjust here.
jp 83 Euro S AT 57k
I believe I indeed need to move the pin further in the WUR.
But I already moved it in when cold start to adjust my cold control pressure from 3 till 1,1 bar
Next I lowered the warm control pressure but apparently engine was not warm enough since driving the car , it is still too high
I will do as you instruct and lower it to 3,1 bar
The problem is that when lowering the warm control pressure by mechanically driving the pin in the WUR, it will also lower my cold control pressure, not?
So I hope I still have enough pressure to cold start the engine
Then I will readjust my CO, it is indeed very sensitive so I will use smaller turns on the CO screw
If you already have cold control down under 1Bar I dont think you need to lower that. If you crack open outlet from WUR when hot, does pressure drop?
jp
If you already have cold control down under 1Bar I dont think you need to lower that. If you crack open outlet from WUR when hot, does pressure drop?
jp
I already cleaned out the WUR.
yes pressure drops when opening outlet.
Could it be that the Bi-metal plate is not working properly : I mean that it bends too much and thus creating a warm control pressure that is too high.
Perhaps I need to slightly bend the bi-metal (before it bends itself by heating the coil around it) so that when cold it has another bend-angle and thus the
end bend status is less than before....
If you already have cold control down under 1Bar I dont think you need to lower that. If you crack open outlet from WUR when hot, does pressure drop?
jp
I found the way to adjust my Warm control pressure : drive out the pressed cilinder (about 0.4inch ) : this will undo some pressure from the bimetal to the spring and thus lowering control pressure :
If anything, tap the cast iron body in the top part outwards, which will reduce pressure. Moving either the cast iron body or the small post (with bi-metallic on it) will change pressures - driving the small pin IN will bring cold control down, moving the cast iron body will move both hot and cold control.
jp 83 Euro S AT 57k
In your WUR , 036 , the middle part , have 2 soft membrane in it and one in metal on top part .
The 2 soft membrane are for the vacuum rich .
See the pictures .
This WUR is for a Porsche 965 Turbo
Here , for 911 SC .
This one is a 086 , Porsche 928 ROW , before I rebuilt it .
12-21-2018, 09:47 PM
