Speaking of WUR
07-18-2007, 02:13 PM
#1
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Speaking of WUR
I have a vacuum operated WUR on my 82 Euro SC. Doesn't seem to be working at all.
Symptoms are bouncing idle at startup for about 30 seconds then stabilizes to a low idle until up to operating temp the idle is at 950.
If I lean out the mix to get rid of the bounce, she is really lean (white plugs and mssing at low RPM).
I've removed the vacuum line from the WUR while cold and the symptoms are the same, so I am assuming the WUR is not doing anything.
Can the vacuum operated WUR's be rebuilt or am I just SOL and need to drop coin on a new one?
thanks.
Symptoms are bouncing idle at startup for about 30 seconds then stabilizes to a low idle until up to operating temp the idle is at 950.
If I lean out the mix to get rid of the bounce, she is really lean (white plugs and mssing at low RPM).
I've removed the vacuum line from the WUR while cold and the symptoms are the same, so I am assuming the WUR is not doing anything.
Can the vacuum operated WUR's be rebuilt or am I just SOL and need to drop coin on a new one?
thanks.
07-18-2007, 02:34 PM
#2
Rennlist Member
1. Never attempt to change/set fuel mixture unless the car is at hot idle, hooked to a CO machine, and tested pre-cat.
2. Changing CO does nothing to help the engine, but can open new cans of worms elsewhere.
3. Actually, it sounds like your WUR is working fine, and that the cold control pressure is possibly set on the rich side of the acceptable range.
If the cold control pressure is set rich the car will have a gentle cold start surge that can last from between a few seconds all the way up to a minute, depending on ambient temp. A rich cold control pressure setting will also offer some protection to your airbox. For what it's worth, I've tested correctly functioning WURs, with and without the vacuum hooked up, almost no noticeable change in result. The only way that you can know if your WUR is working, or what its pressure setting is, is to hang a Bosch control pressure gauge on the engine and measure it. Reset your mixture per factory instructions and enjoy your car.
2. Changing CO does nothing to help the engine, but can open new cans of worms elsewhere.
3. Actually, it sounds like your WUR is working fine, and that the cold control pressure is possibly set on the rich side of the acceptable range.
If the cold control pressure is set rich the car will have a gentle cold start surge that can last from between a few seconds all the way up to a minute, depending on ambient temp. A rich cold control pressure setting will also offer some protection to your airbox. For what it's worth, I've tested correctly functioning WURs, with and without the vacuum hooked up, almost no noticeable change in result. The only way that you can know if your WUR is working, or what its pressure setting is, is to hang a Bosch control pressure gauge on the engine and measure it. Reset your mixture per factory instructions and enjoy your car.