quick CIS/WUR adjusting question

[lagoon]

I have read in previous posts that the cold and warm control pressures are different with the engine off and fuel pump on AND engine running. My question is: which way is the most accurate way to check/adjust the WUR settings? 81'SC

[wckrause]

If your car is US version with O2 sensor, then I don't think it makes a difference.

If you do it with the engine OFF, then you can take your time and not have to worry about your WUR warming up because of rising engine temps. Disconnect the power connection to the WUR for checking cold control pressure. There are graphs in the Bentley manual that shows proper range of pressure vs. ambient temps.

The ROW cars and earlier US versions had a slightly different WUR that had a feature to further reduce control pressure that would only operate with the engine running. You would get two different readings with the engine on and off.



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Bill Krause
'79 911SC Euro
MY PELICAN GALLERY

[lagoon]

thanks alot Bill, that tells me what I need to know!

Originally posted by wckrause:
If your car is US version with O2 sensor, then I don't think it makes a difference.

If you do it with the engine OFF, then you can take your time and not have to worry about your WUR warming up because of rising engine temps. Disconnect the power connection to the WUR for checking cold control pressure. There are graphs in the Bentley manual that shows proper range of pressure vs. ambient temps.

The ROW cars and earlier US versions had a slightly different WUR that had a feature to further reduce control pressure that would only operate with the engine running. You would get two different readings with the engine on and off.