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911st 911st is offline
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Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
Originally Posted by 9dreizig View Post
No mods, it's the same with the stock WUR and the digital one,.. runs rich all the time as well as NO boost. Main issue was when blipped the fuel pressure wouldn't drop no boost just idle to say 3000 rpm. The collective mind trust here said it's pointing towards the fuel head.
I think I'll get it rebuilt just to be on the safe side, it is 34 years old!!
Todd this is a little hard for me to understand what you are trying to say.

I think you are saying:

Stock and D-WUR (new out of the box) both show the same rich condition at all points pre-boost and 'on'-boost.

Control Pressure (not fuel pressure) dose not drop with throttle blipping off idle.

Control Pressure dose drop after 3000rpm.

If this is true, it sounds like both the stock WUR and D-WUR have been tried. Both are probably set to operate as stock. Both show the same rich setting. Thus, it may not be the WUR as both are showing the same response.

The stock 930 WUR dose not lower CP when the throttle is biped. It only dose so when about 5psi of boost is reached. I am not sure how the D-WUR is programed in this regard but I suspect that out of the box it is set to work as the stock WUR. If your CP dose drop at 3000rpm that is consistent with normal boost enrichment which is typically trigered at about 5 psi of boost. Thus, all sounds ok in that regard.

If the stock and D-WUR have the same response it dose not sound like a WUR issue.

If system pressure (fuel pressure?) checks out I would not suspect the FD per say.

If your hot control pressure checks out I would not suspect the WUR per say.

At almost sounds like you could just reset the idle CO to spec and everything should fall back into place.

Intake air temperature changes can effect CO. If your CO was set on a very cold day, CO will be rich on a very warm day. If CO was set to adjust around another issue like an intake leak, restrictive fuel filter, and or dirty FD and this is later corrected. The CO might change.

I would try adjusting the CO (idle air fuel ratio) using the factory adjustment at the metering arm and see if this puts you back where things belong.
Old 03-26-2010, 09:44 AM
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