Digital WUR

[laughingman868]

Has anyone tried the parts klassik digital WUR? I just spent a semi large chunk of time reading through this long thread about the unwired version. Can anyone speak to the quality of the parts klassik version?

We recently moved from CA to CO and my car isn't running very well, which is how I stumbled across the discussion about the unwired digital WUR. I will likely create another thread for WUR/mixture and altitude questions. Thanks in advance for any information.

https://forums.pelicanparts.com/911-930-turbo-super-charging-forum/379783-digital-wur.html

https://www.************.com/p-1337-cis-warm-up-regulator-digital.aspx

[PeteKz]

What year car and engine? What is the part number on your WUR? Was the car running perfectly before the move to CO, or was it running marginally at sea level before you moved?

[laughingman868]

Hey Pete, the vehicle is a 77 S, but it has an 82SC engine in it. It had a rebuild by TRE in the last few years and was running great before the move. Cold starts were a little rough, but it ran very well once warm.

The WUR number ends in 009, and this car did not have the ECU moved over during previous ownership when the engine was swapped.

I have an LM-2 in it and it was reading 12.2 at idle and had a surge, so I leaned it out slightly. Now it’s at about 13.5 cruising and into the 12’s getting on it. However, when I lift off the gas entirely it leans way out and reaches 17-18, which scared me. I never really noticed it doing that at sea level, but I wasn’t really paying attention.

[laughingman868]

Here is an image of the WUR

[pmax]

Originally Posted by laughingman868

Hey Pete, the vehicle is a 77 S, but it has an 82SC engine in it. It had a rebuild by TRE in the last few years and was running great before the move. Cold starts were a little rough, but it ran very well once warm.

The WUR number ends in 009, and this car did not have the ECU moved over during previous ownership when the engine was swapped.

I have an LM-2 in it and it was reading 12.2 at idle and had a surge, so I leaned it out slightly. Now it’s at about 13.5 cruising and into the 12’s getting on it. However, when I lift off the gas entirely it leans way out and reaches 17-18, which scared me. I never really noticed it doing that at sea level, but I wasn’t really paying attention.

Without the lambda box, you have a frankenCIS system with a mish-mash of components.

The 82SC OEM setup uses the 090 WUR. Are you sure it's a 009 not 0090 ?

Lots of good info here, thread title notwithstanding https://forums.pelicanparts.com/porsche-911-technical-forum/758788-cis-troubleshooting-dummies-7.html#post12209997

[PeteKz]

009 would be from an early car. Not sure offhand which year, but before the SC's. I can't be sure from the picture--does it have a vacuum connection (not a breather connection)? The WURs in the 1980-83 SC's did not have vacuum connections because the OXS system provided mixture control and enrichment through a frequency valve (FV).

The AFR should be around 14:1 at idle, and dropping to the range of 12.5:1 at full throttle is normal. 17+ also is normal on extended deceleration.

With the mixed CIS components you have, I would set the AFR close to 14:1 at idle, and make sure it dips into the 12's at full throttle. Don't worry about what happens on deceleration.

What is the part number on your fuel distributor?

[laughingman868]

Pmax, thanks for sending that link, I will give that a read through shortly. I just double checked the WUR and it appears to be a 009.

Pete, I included an image of the WUR with numbers, and one of the fuel distributor.

1) goes to an unknown location on the back of the engine, it connects to a solid line.
2) turns into a solid fuel line and goes to the fuel distributor.
3) goes to the upper fitting on the throttle body

The distributor part number looks like 347916 341.

With my pretty limited understanding of the CIS system, I wasn’t sure if 17-19AFR on deceleration is ok. I have to be sure because I can’t afford another rebuild!!

[boyt911sc]

Laughingman,

Could you post a picture of the throttle body? If your WUR is indeed a -009, don’t expect your ‘82SC motor to run well. Using the wrong WUR plus no ECU is a sure way to make your experience with CIS a bad one. Fuel distributor FD-077 needs an ECU, OXS, and a non-vacuum WUR to control the enrichment process.

Tony

[laughingman868]

Hey Tony, can you tell which TB it is from these images? I have read that mixing CIS parts of different years can lead to problems. I’m hoping that since this car ran well before the move, it’s just the mixture that needs adjusted.

[PeteKz]

From the pictures, it looks to me like the "vacuum" hose from the top of the WUR goes to the breather port on the back (back of the car) of the throttle body. Thus it does not perform vacuum mixture control. Are you sure the last digits stamped on the WUR are 009? If so, then that should go to a vacuum port. Please post a picture of the part number on the WUR.

It's also missing the deceleration valve. That's not necessarily a problem, as I took the decel valve off my car too. Without it, the engine drops RPM faster when you take your foot off the gas, such as when upshifting, so you have to be quicker on your shifts to match RPM and avoid the reengagement jerk.

I agree with Tony that you probably will need to find the OXS system, including Frequency Valve, to add back to your CIS. The FD you have is for the OXS system and is internally different than the earlier FD's because it was designed to work with the OXS. Alternately, you need the non-OXS FD to make it run right, which also requires the lines to the injectors, because the connections on the top of the FD with the OXS are different from the FD without it.

I don't have experience with the digital WUR, but I suspect that you will need the non-OXS system to work with it.

[boyt911sc]

Originally Posted by laughingman868

Hey Tony, can you tell which TB it is from these images? I have read that mixing CIS parts of different years can lead to problems. I’m hoping that since this car ran well before the move, it’s just the mixture that needs adjusted.[LIST]

Correct. So why are you mis-matching the CIS components particularly the WUR? Double check the WUR. You need the following for your FD-077 (shown in the picture):

• WUR-072/-090.
• ECU
• OXS
• Check that the FV is operational.
• Connect the different vacuum hoses correctly.

Then your ‘82 SC CIS will run well.

Tony

[laughingman868]

Good morning, and thanks for helping me look into this over the Holiday weekend!

The WUR part number is 0438 140 009, and the hose that I removed to expose the part number connects to the upper part of the TB, and it was quite loose on the WUR end.

I used my fingers to trace the hard line behind the engine and it goes to the back of the fuel distributor.

The WUR connections are shown again in the images. This is not my TB shown, but one I found online just to illustrate where the vacuum line goes.

I will look for CIS diagrams online for the 77 vehicles and SC to see exactly what I have here, and what needs to be changed. However, if the 17+ AFR on decel isn't an issue, and its in the range you listed for cruising and WOT, I'd prefer not to mess with anything.

[laughingman868]

[laughingman868]

Tony, everything shown was on the car when I purchased it, and I cannot say why the swap wasnt done properly. During the rebuild, I recall the folks at TRE saying that I can have it run well when warm, or when cold, but not both. Maybe this is because of the mismatching parts. Somehow they got it running really well at sea level.

I will spend some time looking up how the OXS and ECU is connected on the later years as I'm not sure if I can just buy these parts and pop them on. I have no idea what wiring was swapped over from the 77 engine, or if this is all from an SC.

Could the OXS and ECU be omitted if I got the digital WUR? I read some not so stellar reviews of the unwiredtools WUR, and I'm not sure of the parts klassik version is any better.

[pmax]

Originally Posted by laughingman868

...
I will look for CIS diagrams online for the 77 vehicles and SC to see exactly what I have here, and what needs to be changed. However, if the 17+ AFR on decel isn't an issue, and its in the range you listed for cruising and WOT, I'd prefer not to mess with anything.

It appears the vacuum enrichment is functioning correctly on accel and adding the OXS/lambda back isn't a trivial task with the additional wiring required so if the only heartburn is the 17+ AFR on decel, I agree with not messing with it and spending the extra $$$$ for the retrofit.

Originally Posted by laughingman868

During the rebuild, I recall the folks at TRE saying that I can have it run well when warm, or when cold, but not both. Maybe this is because of the mismatching parts. Somehow they got it running really well at sea level.

Since this was installed by the TRE pros, perhaps they can offer a suggestion ?

[laughingman868]

pmax, I'd like to see the decel AFR on a properly functioning vehicle to really feel better haha.

I plan to reach out to them this week, but I feel bad spamming them with questions now that we are in CO and will no longer be taking the car there.

I also plan to call parts klassik and ask about their digital WUR.

[pmax]

Can't help you with the decel AFR until I install the sensor unit sitting on the shelf for far too long

Besides that, similar to PeteKz's setup, I run with the decel valve "delete", nipple plugged, on my 80SC, haven't missed it. The decel valve on the 82 is the flying saucer looking doodad with the nipple on the passenger side.

[laughingman868]

Pmax, no problem, maybe someone else can provide some data taken from their vehicle!

I’m gonna see how the car drives and go from there. I can deal with rough cold starts as I never drive it when it’s real cold out.

If I can get the parts to backdate the CIS for a decent price, maybe I’ll go that route. It appears that I’ll need the FD, WUR and different fuel lines.

[boyt911sc]

Originally Posted by laughingman868

Laughingman,

#1 @ WUR is the return line that goes to the backside of the FD (CORRECT).

#2 @ WUR is the control pressure input line from the center of the FD (CORRECT).

#3 @ WUR is the vacuum port for WUR-009 but you have it connected to the WRONG port. #3 @ throttle body is a VENT port NOT a VACUUM port. If you have the CORRECT WUR (-072/-090), it will use port #3. WUR-009 is now connected to a VENT port instead of a VACUUM port. It needs a vacuum port at the back side of the TB.

Where are the 2 hoses (red & blue) of your ignition distributor connected?

Tony

[laughingman868]

Tony, since this is the incorrect WUR, what would happen if I move that vacuum line on the WUR from the vent on the throttle body, to a vacuum port on the rear of the throttle body?


My ignition distributor looks like it’s lacking any blue or red hoses, I believe I may be looking
In the wrong area.

I also just did some reading on the FrankenCIS, that may be an option I explore.

-Brenon