NO Power to my WUR??

[keithbkeller]

Ok Guys, I took my multi-tester and disconnected the electrical plug from the WUR and hooked up my tester to the plug, then turned on the ignition and am getting no measurable electricity power to the WUR? Can someone help me understand why this could be? Thanks!

[rsscotty]

Try testing it with the engine running.

[spuggy]

Originally Posted by rsscotty

Try testing it with the engine running.

What he said. Or temporarily disconnect the air flow sensor lead on a later (post 74, 75? - I know my '77 has it) CIS motor, the one intended to stop the fuel pumps running if the motor is stopped (so it doesn't spray fuel into the wreck if you're upside down).

The WUR is on the same circuit, IIRC. You could also deflect the air flow sensor plate - but this will start the pumps AND squirt fuel through the injectors - valid for some reasons, but probably not what you want to do here.

The cold start valve and the air flow sensor plug are very close and have very similar connectors; different colors is all.

[boyt911sc]

For '76-'83 CIS engines, the WUR electrical plug could be tested for power by:
1). Concecting terminals #87a and #30 (FP relay socket) with a suitable jumper preferably with in-line fuse. Fuel relay has to be removed.
2). Turn ignition switch to ON position (not start).

In summary, follow the typical FP test procedure. The WUR's for these cars ('76-'83) get power from terminal #30. Keep us posted.

Tony

[RarlyL8]

Your WUR is getting power, I guarantee it. If not your car would flood out as the engine warms.

Learning about CIS operation is a good thing however your issue is isolated to cold start so that is where the concentration should be. Once you get your gage set we will walk you through the testing and cold pressure adjustment.

[keithbkeller]

Ok Guys, I have now disconnected the WUR and not only does the car start but it is the same with or without the WUR connected with the electrical plug. So can someone tell me where the fuse or relay is for the WUR? I need to hook figure out how to get power back to the WUR? Thanks, Keith

[timmy2]

It will start disconnected as it only uses the power when running to heat the bimetallic strip and lean out your mixture.
Tony told you how to check it, jumper your red fuel pump relay socket and turn the ignition to run.
Then check the voltage at the wur connector wires.
Or, start the car and with it running check with it disconnected like you have it now

[john walker's workshop]

just start the engine and check it at idle. should have 12V and ground. the red w/white trace wire which goes through the 14 pin connector on the left rear panel. maybe a crusty connection there. comes from the fuel pump relay up front.

[boyt911sc]

Originally Posted by john walker's workshop

just start the engine and check it at idle. should have 12V and ground. the red w/white trace wire which goes through the 14 pin connector on the left rear panel. maybe a crusty connection there. comes from the fuel pump relay up front.

Keith,

If you don't get power @ WUR's plug while the engine is running, the problem could be @ terminal #10 (14-pin connector) red/white wire or the brown wire has no ground contact. Power @ red/white wire and ground contact for the brown wire in order for the WUR to get energized. Keep us posted.

Tony

[j911brick]

Also test the AAR for power since its on the same circuit as the WUR.

[keithbkeller]

Hi Guys, Here are the readings I needed to provide; (1981 911 SC)
Outside temperature is 75 F
Valve closed pump running pressure is; 3-BAR
Valvue open pump pressure 2.1- BAR
Valve open pump running WUR plugged in pressure (warm) control pressure 2.9-BAR
Valve open after warm pressure; Residual pressure Immeadiately after turning car off; 2.9, after 30 seconds 2.7, after 60 seconds 2.6, after 120 seconds 2.3
after 15 minutes 1.7, after 30 minutes 1.7
Note; I inadvertently drove this car around yesterday with the WUR electrical connection unplugged with no adverse effects. Its like the fuel is just pumping through the WUR with it having no effect on anything cold or hot.
However it was around 75 degrees yesterday during my drive.
Please give me your input. Thanks! Keith

[RarlyL8]

You drove it around with the WUR unplugged and it ran perfect as before?
What are the AFRs?
The only way that is possible is if the CIS has been adjusted to compensate for a non-functioning bimetallic strip. If that is the case the engine would have a difficult time starting as the system is now static instead of dynamic.
Something very goofy going on here ...

[keithbkeller]

What is a AFR? The car starts right up and sputters to life and then runs strong. The Voltage test in the electrical connector of the WUR just keeps climbing when set to "DC-V" I can't get a consistant reading.

[keithbkeller]

Ok so is a rebuilt WUR goina cure my problem?

[boyt911sc]

Originally Posted by keithbkeller

Ok so is a rebuilt WUR goina cure my problem?

Keith,

What made you think you need a new WUR? Have you tested it? Nobody could stop you from buying a replacement WUR and try swapping parts until you fix the problem. That's an expensive way to do troubleshooting unless you don't mind the unnecessary expenses. But before you do that, would it be more prudent to test the WUR and find out if it good or bad? Check the control fuel pressures at different time. Example: after start, 30, 60, 90, 120 sec........up to 4 or 5 mins.

Use a test light (12-volts) and check the plug (WUR) when the FP is running. Then do the suggested test above (control pressures versus time).



It is more rewarding helping other people diagnose their CIS problem/s than selling them parts they really don't need (??). Keep us posted.

Tony