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pilcodraw
Join Date: Sep 2007
Location: Pittsburgh Area
Posts: 30
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wur question
Can anyone tell me if the connection to the wur should have 12 volts to it when the ignition is turned on? Or, does the engine have to be running for there to be 12 volts? I am having a cold start problem. The engine starts but runs poorly until it warms up. Then it runs fine. When the engine is off and the ignition is turned on, there is no voltage to my wur..
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11-20-2009, 03:28 PM
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Registered
Join Date: Oct 2005
Location: Capistrano Beach, Ca.
Posts: 7,235
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Typically, the WUR will not have current when it is warm. You did not post the year of your car, but CIS cars after 75 have a thermo time switch which interrupts current to the WUR when the engine is warm or the ignition has been on for a while. If the engine is cold, there should be current to the WUR.
Your cold start issue is likely from an out of spec cold controlled pressure from the WUR, which would not be caused by lack of current to the heating element. You should begin by using fuel pressure gauges to measure your cold controlled fuel pressure, it's probably too high and causing a lean condition. As the engine warms and the WUR warms, the pressure should rise to lean out the fuel mixture and that is apparently what is happening. Do a search for "WUR pressure test" on this forum and you will find lots of threads explaining the procedure for testing. If you don't have a set of fuel gauges, invest in them now--well worth the money and absolutely necessary to trouble-shoot the CIS system. Let us know what you find, and post your car year and model in your signature or screen name ID so all will know how to best respond you your questions.
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L.J. Recovering Porsche-holic Gave up trying to stay clean Stabilized on a Pelican I.V. drip Last edited by ossiblue; 11-20-2009 at 05:12 PM.. |
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11-20-2009, 05:04 PM
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Registered
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Cis wur........
Quote:
The CIS WUR in 911 cars ('76-'83) will only get power when the FP is energized. Since you did not mention the year and model of your car, I would venture to describe the wiring set-up for '76-'83 CIS. At the FP relay socket terminal #30, the following are connected: FP and in pararell arrangement are WUR, AAR, thermo valve (available in '77 onwards). For '75, it has a different wiring set-up. The WUR has a relay of its own and will get energized when the alternator starts to run (engine running). The FP has no relay and starts to run when you turn the ignition switch to RUN position. The TTS (thermotime switch) has no relation to WUR's performance. It is located in a totally separate circuit. What TTS does is provide ground contact to complete the circuit for CSV to function when engine is cold. When engine is warm, the TTS opens up and loses ground contact thus the CSV does not get energized during start. What year is your car? Tony Last edited by boyt911sc; 11-20-2009 at 06:41 PM.. |
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11-20-2009, 05:50 PM
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Registered
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CIS troubleshooting with pressure gauge........
Clippy,
Get hold of a fuel injection fuel pressure gauge and check your fuel pressures. The cold control and system pressures will tell you a lot about your WUR . At this point, I am assuming that your ignition and timing are set correctly. If you don't have one, I suggest that you get one for $60 from a well known supplier (???). This is probably the best $$$ I spent for my CIS DIY work. Keep us posted. Tony Last edited by boyt911sc; 11-21-2009 at 06:10 PM.. |
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11-21-2009, 06:01 PM
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Somewhere in the Midwest
Join Date: Oct 2001
Location: In the barn!
Posts: 12,499
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Could just be an ambient temperature thing. iPhone view doesn't allow me to see your info so I don't know where you are, but if your car was fine when it was warmer outside and now it's having rough cold stars it could just need a mixture adjustment to cope with the cooler temps.
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11-21-2009, 08:17 PM
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