My 928 82 CIS Tour de France marathon
08-03-2011, 08:26 AM
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My 928 82 CIS Tour de France marathon
OK.
I have replaced the fuel filter.
I have replaced the plugs & wires.
I dissasembled and cleaned the WUR, and "Upknocked" the front pin in preparation for setting the Cld Control Pressure.
I have replaced some fuel lines with dash3 A-N braided lines, and have installed a full time fuel pressure gauge just before the WUR.
I got the car to run between 1000-2500 RPM, but not idle.
Cold Control Pressure was around 4.5 bar.
Pin tapping only brought it down to ~3.8 bar.
after a few minutes, Warm Control Pressure settled at 3.2 bar.
System held control pressure at 3.2-3.5 bar for at least a few minutes after turning off..
In Summary,
Warm Control seems OK, but Cold Control is high.
So what is this telling me, oh benevolant CIS-Whisperers ?????
I have replaced the fuel filter.
I have replaced the plugs & wires.
I dissasembled and cleaned the WUR, and "Upknocked" the front pin in preparation for setting the Cld Control Pressure.
I have replaced some fuel lines with dash3 A-N braided lines, and have installed a full time fuel pressure gauge just before the WUR.
I got the car to run between 1000-2500 RPM, but not idle.
Cold Control Pressure was around 4.5 bar.
Pin tapping only brought it down to ~3.8 bar.
after a few minutes, Warm Control Pressure settled at 3.2 bar.
System held control pressure at 3.2-3.5 bar for at least a few minutes after turning off..
In Summary,
Warm Control seems OK, but Cold Control is high.
So what is this telling me, oh benevolant CIS-Whisperers ?????
08-03-2011, 12:36 PM
#2
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Do you have a full set of CIS test gauges?
If so, there is a complete step-by-step tutorial that will walk you through the troubleshootiong and repair process.
Can someone help with the link?
If so, there is a complete step-by-step tutorial that will walk you through the troubleshootiong and repair process.
Can someone help with the link?
08-03-2011, 07:47 PM
#3
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Warm control sounds good - mine runs close to that. Did you have to use throttle to hold 1000rpm, and it died if you let it off? If so, unscrew the front idle screw (large dia slotted head) until you get some control over idle. If there are still problems, check for air leaks - CIS HATES air leaks! to lower cold control, you need to tap the pin in some more, but go slowly, as if you go too far you will also lower hot control, and she will go rich.
jp 83 Euro S AT 53k
jp 83 Euro S AT 53k
08-03-2011, 11:05 PM
#4
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If cold control is high, it probably means the screen in the WUR is partly blocked. You have adjusted your warm control pressure so that is comes out ok. adjusting the cold is trickier. Here are the things that effect the cold pressure:
1) The system pressure
2) The hole in the FD gasket
3) The screen in the WUR
So, you have three options to try to bring your cold pressure into spec.
1) Build some sort of inline Jet to add further restriction to the fuel coming from the FD to the WUR.
2) Replace the screen in your WUR with something hand fabbed out of raw screen from McMaster.com
3) Have your WUR rebuilt (they should be able to do the above)
4) Replace your WUR
It sounds, though, like the car does not idele when warm and it sounds like your warm pressure is good. I think you have some other issue. My guesses (in no particular order)
1) air leak
2) timing
3) idle mixture adjustment
4) idle speed adjustment
I have found the idle behavior to be very sensitive to 3 and 4
1) The system pressure
2) The hole in the FD gasket
3) The screen in the WUR
So, you have three options to try to bring your cold pressure into spec.
1) Build some sort of inline Jet to add further restriction to the fuel coming from the FD to the WUR.
2) Replace the screen in your WUR with something hand fabbed out of raw screen from McMaster.com
3) Have your WUR rebuilt (they should be able to do the above)
4) Replace your WUR
It sounds, though, like the car does not idele when warm and it sounds like your warm pressure is good. I think you have some other issue. My guesses (in no particular order)
1) air leak
2) timing
3) idle mixture adjustment
4) idle speed adjustment
I have found the idle behavior to be very sensitive to 3 and 4
08-04-2011, 02:58 AM
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Warm control sounds good - mine runs close to that. Did you have to use throttle to hold 1000rpm, and it died if you let it off? If so, unscrew the front idle screw (large dia slotted head) until you get some control over idle. If there are still problems, check for air leaks - CIS HATES air leaks!
Yep.....only with throttle.
to lower cold control, you need to tap the pin in some more, but go slowly, as if you go too far you will also lower hot control, and she will go rich.
jp 83 Euro S AT 53k
Yep.....only with throttle.
to lower cold control, you need to tap the pin in some more, but go slowly, as if you go too far you will also lower hot control, and she will go rich.
jp 83 Euro S AT 53k
Hot Control didn't change.
08-04-2011, 03:08 AM
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If cold control is high, it probably means the screen in the WUR is partly blocked. You have adjusted your warm control pressure so that is comes out ok. adjusting the cold is trickier. Here are the things that effect the cold pressure:
1) The system pressure
2) The hole in the FD gasket
3) The screen in the WUR
But wouldn't ALL of these also boost Hot pressure???
I took WUR apart, and sprayed screen (which looked spotless anyway) mercilessly with carb cleaner.
So, you have three options to try to bring your cold pressure into spec.
1) Build some sort of inline Jet to add further restriction to the fuel coming from the FD to the WUR.
2) Replace the screen in your WUR with something hand fabbed out of raw screen from McMaster.com
3) Have your WUR rebuilt (they should be able to do the above)
4) Replace your WUR
It sounds, though, like the car does not idele when warm and it sounds like your warm pressure is good. I think you have some other issue. My guesses (in no particular order)
1) air leak
2) timing
3) idle mixture adjustment
4) idle speed adjustment
I have found the idle behavior to be very sensitive to 3 and 4
1) The system pressure
2) The hole in the FD gasket
3) The screen in the WUR
But wouldn't ALL of these also boost Hot pressure???
I took WUR apart, and sprayed screen (which looked spotless anyway) mercilessly with carb cleaner.
So, you have three options to try to bring your cold pressure into spec.
1) Build some sort of inline Jet to add further restriction to the fuel coming from the FD to the WUR.
2) Replace the screen in your WUR with something hand fabbed out of raw screen from McMaster.com
3) Have your WUR rebuilt (they should be able to do the above)
4) Replace your WUR
It sounds, though, like the car does not idele when warm and it sounds like your warm pressure is good. I think you have some other issue. My guesses (in no particular order)
1) air leak
2) timing
3) idle mixture adjustment
4) idle speed adjustment
I have found the idle behavior to be very sensitive to 3 and 4
A) Fuel Mixture (via Injector in a jar)
B) Idle Speed adjustment.
C) Check timing
08-04-2011, 03:19 AM
#7
Rennlist Member
If the blockage in the WUR is only sufficient to produce a back pressure of x, with minimal pressure from the internal spring on the regulator diaphragm, then x will be your cold control. If x is higher than it should be cold, then thats what you are seeing. If you have a source of compressed air (not too high - 75psi-ish), try blowing it in through the WUR OUTLET, with some solvent (carb cleaner), until you get something out the inlet port. If you cant get anything through, you might have to open the WUR up, dismantle the regulator part, and blow through the inlet and outlet holes from inside - watch for debris, or the gauze filter, being blown out. If this lowers the cold control too far, or makes hot control too low, you may need to adjust the pin setting to get back to the right values.
To check for air leaking into system, with engine running, spray something slightly flammable around all joints and hoses in the inlet system, and watch/listen for a change in rpm or note. Rotten, cracked rubber parts are most likely sources.
jp 83 Euro S AT 53k.
To check for air leaking into system, with engine running, spray something slightly flammable around all joints and hoses in the inlet system, and watch/listen for a change in rpm or note. Rotten, cracked rubber parts are most likely sources.
jp 83 Euro S AT 53k.
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08-04-2011, 12:29 PM
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seems rather odd that the control pressure would drop as the engine warms up. The internal mechanism on the WUR should do exactly the opposite. Could the bimetallic strip be in upside down?
08-04-2011, 07:34 PM
#9
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I guess it could be upside down...time to remove and open again?
Diagrams can be found in my old document here....
http://www.landsharkoz.com/images/pdf/wurfix.pdf
jp 83 Euro S AT 53k
Diagrams can be found in my old document here....
http://www.landsharkoz.com/images/pdf/wurfix.pdf
jp 83 Euro S AT 53k
08-06-2011, 04:41 AM
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Today's Progress (?)
Set Up Jumper with remote switch on 15 foot lead
Pulled out #1 Injector, placed in test jar.
Ran Fuel Pump......a lot of the right sounds......3.2-3.4 Bar Control pressure....
Injector # 1........struggling to blow mist.
Reinstalled #1 injector,
Removed Injector #5, placed in test jar.
Spray pattern not bad, but INTERMITTENT?????
BUT .....control pressure doesn't budge.
Immediate thoughts > Dirty Injectors.
After coming inside, realized that I can run the Injection line without an injector, straight into the test jar, to see if supply is smooth or intermittent.
If it is intermittent, I need to check Fuel Pump delivery (volume & Pressure).
If that's not it....I guess I'm up for the FD rebuild
Porsche enjoyment...
Set Up Jumper with remote switch on 15 foot lead
Pulled out #1 Injector, placed in test jar.
Ran Fuel Pump......a lot of the right sounds......3.2-3.4 Bar Control pressure....
Injector # 1........struggling to blow mist.
Reinstalled #1 injector,
Removed Injector #5, placed in test jar.
Spray pattern not bad, but INTERMITTENT?????
BUT .....control pressure doesn't budge.
Immediate thoughts > Dirty Injectors.
After coming inside, realized that I can run the Injection line without an injector, straight into the test jar, to see if supply is smooth or intermittent.
If it is intermittent, I need to check Fuel Pump delivery (volume & Pressure).
If that's not it....I guess I'm up for the FD rebuild
Porsche enjoyment...
08-06-2011, 04:52 AM
#11
Rennlist Member
You can still load the tank with a couple of bottles of Techron, and run the pump for an hour or so - as long as you are there with it to catch any mishaps! I wouldnt expect control to budge, maybe system would fluctuate a bit, but if delivery rate is in spec (1350ml/30 secs), it shouldnt move much. Without a stop **** in your pressure gauge set up, you cant measure system pressure, unless you can find a way to safely block the WUR outlet - ball bearing under the pipe end?
jp 83 Euro S AT 53k
jp 83 Euro S AT 53k
08-06-2011, 10:08 AM
#12
Race Car
I wish I'd caught that idea of just running the system in a loop without firing the engine when I was locked in battle with it years ago. I was essentially doing that when running these same tests, but never throught to (or remembered, at least) to put some cleaner in there and just circulate. Seems like a good precaution after seasonal storage once a system is squared away. Still a double-edged sword though.
Wonder if this car has the hot start valve, and that could be malfunctioning somehow.
Total WAG and not a problem that I've read before...
Keep at it- many told me that once the system is good to go, its a matter of turning the key each spring. So far that has held true for me for several years of very limited/occasional use.
Wonder if this car has the hot start valve, and that could be malfunctioning somehow.
Total WAG and not a problem that I've read before...
Keep at it- many told me that once the system is good to go, its a matter of turning the key each spring. So far that has held true for me for several years of very limited/occasional use.
