Trying to adjust Fuel Mixture on 930 for elevation

[jwakil]

I've moved my 930 from Texas to Colorado and sense it is running a little rich, so was trying to lean it just a hair. What puzzles me is that my adjustment mechanism seems a little different than all the pictures and videos I've seen. I was expecting to have a hole between my fuel distributor and throttle body where you stick the 3mm allen key into. Instead, I have a tube that sticks out as shown in the picture. When I put my allen key in there, I can feel a spring I can push down on, which goes quite a way down. I was also expecting that when I turn the key, it should have distinct clicks. However, when I turn the key I can feel slight resistance but there are no clicks. So I'm not sure if the key is not engaging or I need to push down on the spring. I don't want to turn too much and mess up the mixture totally. Should I be pushing down on the spring, and should I be feeling clicks or not. Why do I have this tube sticking out unlike others?

[908/930]

I think the tube is normal. It's been a while, push against spring should feel key engage, no click when turning. Only requires small turn to adjust.

[mark houghton]

As already described. Spring loaded adjustment post. Just keep pushing down gently until you feel resistance, at which point when you turn your allen wrench you will feel it engage. If you continue pushing down you'll end up deflecting the metering arm and you'll see the rpms drop due to overly rich condition. Very small turns, just a degree or so at a time

[dos531]

Sounds like its working as its supposed to, but that mainly changes the mixture at idle.

[jwakil]

Originally Posted by dos531

Sounds like its working as its supposed to, but that mainly changes the mixture at idle.

yes after further research it seems if I want to adjust mixture at non-idle I need to adjust the WUR. At this point it doesn't run too bad, just feel slightly sluggish and less power (probably because of the thinner air) so reducing fuel wouldn't increase power. So I will leave as is for now. In the summer time when the air becomes even less dense is when I might need to do something.

[jwakil]

My warm up regulator is as shown, which I believe the previous owner made adjustable. I know the screw marked A is for the cold fuel pressure adjustment. I would raise up the screw to lean and go down to richen. How do I adjust the hot fuel pressure? Is that the blue screw mechanism marked B?

[Bucketlist]

If you have the BL Adjustable Wur it will look like this on the bottom and you can carefully snake a 4mm allen wrench under the wur into the hole and adjust. I adjust mine when the car is warm, engine not running and fuel pumps running with battery charger attached while watching fuel control pressure on a gauge. Warm pressure about 3.65 bar or 53 psi warm.

[dos531]

I have the pdf manual for the adjustable wur if you need it. PM me your email and ill send it to you.

[Alan L]

You should not be fiddling with 'A' unless your WUR is out of whack - ie needs some remedial work.
The mixture adjustment you seek is as shown by Buckelist.
But without proper AFR numbers your are shooting in the dark, going by feel.
Mine does go rich at 3000 ft ASL - it makes a difference.
Alan

[flightlead404]

I'm not sure why you would ever need to adjust it for altitude.

The device is a mass flow meter, not a volume meter.

[Alan L]

Hmm, that makes sense. You wouldn't expect it to be so non- compensating. But my AFrs are richer at 3000 ft. I do tweek the WUR. Have a higher pressure setting. But for normal use it probablyu wouldn't matter. But I am trying to get the last bit out of it.
Alan

[Alan L]

That would suggest the airplate does not fully open at altitude at WOT?
Alan

[dos531]

In theory the afm should compensate for altitude somewhat, but in my experience it does a very poor job. Yet another reason the CIS belongs in the garbage.

[66cal912]

You should hit up Jacob, he's in Colorado too, and running his car in all the high altitude mountains. He has a build thread on here: https://forums.pelicanparts.com/911-930-turbo-super-charging-forum/853761-its-about-time-finally-have-79-930-a.html

or you can DM him on Instagram, https://www.instagram.com/jacob.schramm/.

He's running a later 964 turbo WUR part number: 0438140160 that is able to compensate for altitude better some how, which the original 930 wur struggled with at altitude. I picked one up on Ebay a couple years back but have yet to have it overhauled for my 930. He said it was a huge improvement for the altitude variation he was getting from his original WUR. Its possible he has more details in his detailed car thread.

The base of it is much thicker so it has something else going on inside compared to a normal WUR. there is one here, which you can see has a much larger lower section but the price on this one is a bit nuts..

https://www.fuelinjectionproducts.com/products/porsche-911-reman-warm-up-regulator-bosch-0438140160?srsltid=AfmBOoqxxlHhXzh7TgASQ01dgcj8MWn o8B2iutBJ3l_Eha6f-suESUOL

[gorskined]

Originally Posted by jwakil

My warm up regulator is as shown, which I believe the previous owner made adjustable. I know the screw marked A is for the cold fuel pressure adjustment. I would raise up the screw to lean and go down to richen. How do I adjust the hot fuel pressure? Is that the blue screw mechanism marked B?

im curious what is screw B? im guessing a blocked off port that was installed to monitor real time control pressure while the engine is running?

[Bucketlist]

"What is that the blue screw mechanism marked B?"

Maybe it used to look something like this.....

[RarlyL8]

The plug marked "B" in your picture on past #6 does look like an a gauge fitting. It should be removed and the proper fitting put back.
The adjustment customization labeled "A" in your picture is for cold pressure only and is typically an indicator that the WUR is failing. There is no need to change CCP specs on a properly functioning WUR.
930 CIS does not compensate for altitude, that is done using the idle adjustment screw. If your altitude changes significantly, which is not a normal thing, you may need to give it a tweak same as you would for a carburetor.
964Turbo CIS does compensate for altitude. The -160 and -164 WURs have an extra diaphragm that sees atmosphere and deflects accordingly. Using one of these will solve the problem if you live in the mountains and frequently change elevations. The CCP and WCP should be close enough for a plug and play if using a -145 fuel distributor. A tweak of specs would be beneficial if using a -037 or -016 fuel distributor.

[Mr. Merk]

Originally Posted by 66cal912

You should hit up Jacob, he's in Colorado too, and running his car in all the high altitude mountains.

I second this. He and the rest of the Colorado Turbros have wideband AFR gauges in their cars and have this down to a science.

[jwakil]

Originally Posted by RarlyL8

The plug marked "B" in your picture on past #6 does look like an a gauge fitting. It should be removed and the proper fitting put back.
The adjustment customization labeled "A" in your picture is for cold pressure only and is typically an indicator that the WUR is failing. There is no need to change CCP specs on a properly functioning WUR.
930 CIS does not compensate for altitude, that is done using the idle adjustment screw. If your altitude changes significantly, which is not a normal thing, you may need to give it a tweak same as you would for a carburetor.
964Turbo CIS does compensate for altitude. The -160 and -164 WURs have an extra diaphragm that sees atmosphere and deflects accordingly. Using one of these will solve the problem if you live in the mountains and frequently change elevations. The CCP and WCP should be close enough for a plug and play if using a -145 fuel distributor. A tweak of specs would be beneficial if using a -037 or -016 fuel distributor.

Yes, I think screw B was for a gauge. I'll hit up Jacob. I think the car is fine at 5k feet, but some of the mountains here go up to 10k+, and I had a hard time starting the car when I got up there. I'm thinking the idle mixture might be all that I need to adjust but that is counter to several other postings I've read. Another thing I'm thinking of is going with a Zork tube, which I've been thinking of and which would make it run a little leaner by default.

[jkkarrow]

Looks good