WUR....what does it really do?

[MD540iT]

Well at this stage in my Fuel issue saga....im starting to wonder what the point of the WUR is??

So I attmpeted to drive the car again, and all seems ok at first (running with the O2 disconected) its "driveable" but last time, I went to a friends house, and car was parked for a couple hours, came back and car barely starts and is barely idling, the A/F is 19-20+, Im thinking the WUR has heat soaked, so I enriched the mixture and drove home.

about an hour or 2 later I said, lets see what happens, So I try and move the pin(richen) the WUR... but it doesnt get any better. Then I swap WUR, with a "cold" one and see, sure enough it runs in the "normal" AF. Ok great....Next day I think its fixed and I can go for a drive up to the mtns. I drive and seems ok, I park for aboout 30 min, come back.....and guess what? A/F is way lean again!!!!

W T F!!!!!


So what if I take the "warm up" part out? I should be able to start it, and then set it. with out the WUR changing things. as it heats up.

[GaryR]

WUR, huh, yeah
What is it good for?
Absolutely nothing, uhh
War, huh, yeah
What is it good for?
Absolutely nothing
Say it again, y'all
War, huh (good God)
What is it good for?
Absolutely nothing, listen to me, oh

Sorry, had to.

[Schulisco]

Originally Posted by MD540iT

So what if I take the "warm up" part out? I should be able to start it, and then set it. with out the WUR changing things. as it heats up.

I guess a cold start will be impossible under several ambient temperatures and conditions.

The Warm Up Regulator manages the control pressure of the fuel distributor. FD is required to have a proper managed cp on all driving conditions. It depends on your car which WUR version is installed. Some have a vacuum connection to manage driving on higher altitudes to lean the mixture, some have an additional vacuum connection to manage load on the engine while accelerating to enrichen the mixture. They differ in the control pressure curves depending on the engine. Guess it's a lambda controlled SC? Which model year, which engine code?
When you disconnect O2 the ECU goes into the "limb home mode" with a fixed duty cycle of 50% for the pulse valve on cruise and idle. You'll loose power and buy addtional fuel consumption.
Check the WUR if you got the correct version for your car, let it overhaul and get happy with a nice startiing engine and a fuel efficient and performing car under any conditions.

Thomas

[MD540iT]

Originally Posted by Schulisco

I guess a cold start will be impossible under several ambient temperatures and conditions.

The Warum Up Regulator manages the control pressure of the fuel distributor. FD is required to have a proper managed cp on all driving conditions. It depends on your car which WUR version is installed. Some have a vacuum connection to manage driving on higher altitudes to lean the mixture, some have an additional vacuum connection to manage load on the engine while accelerating to enrichen the mixture. They differ in the control pressure curves depending on the engine. Guess it's a lambda controlled SC? Which model year, which engine code?
When you disconnect O2 the ECU goes into the "limb home mode" with a fixed duty cycle of 50% for the pulse valve on cruise and idle. You'll loose power and buy addtional fuel consumption.
Check the WUR if you got the correct version for your car, let it overhaul and get happy with a nice startiing engine and a fuel efficient and performing car under any conditions.

Thomas

this is a turbo, I have disconnected the vac/boost port. (because it goes to rich)

I have 3 WUR's if 2 of them both go rich after heat soak, despite being adjustbale.....
I just pulled the Bi-metallic strip out of the 3rd one and will try that

[MD540iT]

Ok I just went and installed the WUR with out the "warm up" parts. initial pressure was 45. started normally. I tried to drop the pressure with the allen but it didnt drop any more. (I was able to raise it however)
SO next I took the bottom half of the WUR off so there was no spring/pin, just what ever it naturally would be at and that was 42 psi. didn't drive it or let it get hot, but might try that next.

[Schulisco]

Which model year and engine code?

[T77911S]

Originally Posted by MD540iT

Ok I just went and installed the WUR with out the "warm up" parts. initial pressure was 45. started normally. I tried to drop the pressure with the allen but it didnt drop any more. (I was able to raise it however)
SO next I took the bottom half of the WUR off so there was no spring/pin, just what ever it naturally would be at and that was 42 psi. didn't drive it or let it get hot, but might try that next.

thats the WRONG thing to do.

when you have a problem dont go modifying things from how it was designed.
you want everything to spec.

the WUR does not really "regulate" as its name implies. it just changes the mixture, by changing control pressure, for cold starts and hot running and with the turbo making it richer under boost.

if you go too rich under boost it could something as simple as an air leak on the pressure side. or if you vent your BOV to atmosphere it could be opening when it shouldnt.

you HAVE to have gauges.
you need to know the cold pressure, hot pressure and pressure under boost.
you can buy a hand vac that will also pressurize the WUR to check control pressure under boost.

with all you have done to your WUR i would send it off and have it modified and set to spec.

you need to provide more info about your car

[T77911S]

i thought your problem sounded familiar from the 930 side.
good luck

[AlKidd]

You really didnt have to. Now its stuck in my head.

Originally Posted by GaryR

WUR, huh, yeah
What is it good for?
Absolutely nothing, uhh
War, huh, yeah
What is it good for?
Absolutely nothing
Say it again, y'all
War, huh (good God)
What is it good for?
Absolutely nothing, listen to me, oh

Sorry, had to.

[boyt911sc]

MD,

What is the Bosch ID # (0-438-140-XYZ) on your WUR? You need to test and verify the settings of your WUR using a pressure gauge if they are still in specification. If they are out of spec, you need to recalibrate the settings in order for the WUR to work correctly. Keep us posted.

Tony

[MD540iT]

Well, FWIW, it seems to run better with the "open" WUR and not being effected by heat soak.

[RDM]

Why have you decided the WUR is the problem in the first place?

I presume the allen screw you are adjusting is the one on the fuel distributor. If this is so, I think you need to take about three steps back, learn a lot more about how the system is supposed to work, then humbly start over under the guidance of the shop manuals, someone like Tony, or the CIS for dummies thread.

Willy-nilly adjustment and parts swapping is unlikely to lead to an optimal outcome.

[boyt911sc]

Originally Posted by boyt911sc

MD,

What is the Bosch ID # (0-438-140-XYZ) on your WUR? You need to test and verify the settings of your WUR using a pressure gauge if they are still in specification. If they are out of spec, you need to recalibrate the settings in order for the WUR to work correctly. Keep us posted.

Tony

MD,

You are not doing the right way to troubleshoot your CIS problem/s. So far, all your WUR’s exhibit out of spec for control fuel pressures because you made the wrong adjustment procedures. If you would share with us the Bosch ID #’s of these WUR’s, people with experience could give you a meaningful advise. So far, you have been unresponsive to this request. Good luck.

Tony

[1979-930]

No fuel pressure gauge and No AFR gauge.
I hope for you’re sake it’s too rich. Otherwise POP goes the engine.


Sent from my iPhone using Tapatalk

[T77911S]

Originally Posted by MD540iT

Well, FWIW, it seems to run better with the "open" WUR and not being effected by heat soak.

there is very little heat on the top of the 930 engine.

set the WUR to spec and find the REAL problem.

i spent probably 2 yrs, maybe more (off and on) trying to fix a very lean cruise condition.
i did a LOT of experimenting and testing with fuel pressure AND control pressure.
in the end i had a bad FD (cast iron) even after being rebuilt twice.

set it back to spec
make sure all the CP are correct. even under boost.
buy a hand vac that can also pressurize and check the WUR CP for boost.
make sure NO air leaks on the pressure side.
for me, even venting my BOV to atmosphere had an effect on AFR.
make sure system pressures are steady and good.
check fuel flow per spec to WUR and out of FD.

[MD540iT]

Originally Posted by boyt911sc

MD,

You are not doing the right way to troubleshoot your CIS problem/s. So far, all your WUR’s exhibit out of spec for control fuel pressures because you made the wrong adjustment procedures. If you would share with us the Bosch ID #’s of these WUR’s, people with experience could give you a meaningful advise. So far, you have been unresponsive to this request. Good luck.

Tony

one of the WURs # is 0458140 (916)

[MD540iT]

Originally Posted by T77911S

there is very little heat on the top of the 930 engine.

set the WUR to spec and find the REAL problem.

i spent probably 2 yrs, maybe more (off and on) trying to fix a very lean cruise condition.
i did a LOT of experimenting and testing with fuel pressure AND control pressure.
in the end i had a bad FD (cast iron) even after being rebuilt twice.

set it back to spec
make sure all the CP are correct. even under boost.
buy a hand vac that can also pressurize and check the WUR CP for boost.
make sure NO air leaks on the pressure side.
for me, even venting my BOV to atmosphere had an effect on AFR.
make sure system pressures are steady and good.
check fuel flow per spec to WUR and out of FD.

Yes, you might be right. I really want to go EFI, just want it to run decent until I do.

But I am now having a similar problem, where it is running lean while cruising down the hwy, no matter where I set the idle AFR.

What are the possibilities it could be a stuck/leaking Recirc/BOV?? I was thinking it might be bleeding pressure back up into the fuel meter.

[boyt911sc]

Originally Posted by MD540iT

one of the WURs # is 0458140 (916)

MD,

Go back and review the numbers on your WUR. Clean and read the numbers again. It should be 0-438-140-xyz. The last 3 digits identify what particular WUR you have. 916 is the casting number, ignore this one. What we need are the last 3 digits (hand stamped) on the WUR.

The pictures below are examples:





Tony

[MD540iT]

one of the 3 i have ends in 091

[boyt911sc]

Originally Posted by MD540iT

one of the 3 i have ends in 091

What are numbers for the other 2 WUR’s you were playing around? Why are you too secretive about sharing these information? How do you expect people to help you if you are withholding critical information? We don’t even know the year and model of the engine. Are you working on a 924?

Tony