Problem warm-up regulator

[NWEXCOP]

Anyone have an answer to a problem with a warm up regulator on a 75 Carrera?
Car is new to me, starts and dies until warmed up and after that runs great.
I had my mechanic make a check and the warm up regulator seems to be the problem
and they are not or seldom available,
What is the answer?
Thanks, John

[RarlyL8]

Likely needs a rebuild. What is the Bosch part number (0.438.140.xxx) stamped on the top? -033? I probably have one in stock.

[john walker's workshop]

The WUR is the last thing you adjust after timing, mixture, fuel pressure checks and other base adjustments. It gets blamed for a lot of stuff that originates elsewhere. Is the auxilliary air regulator working or does the car have a hand throttle? What is the CO setting now, hot at 1000 rpm idle?

[Paulporsche]

While John Walker is correct, the WUR is a common failure for these cars. But so are many other items, as he mentions.

There are a lot of threads on the subject of poor starting and running. You should use the search function and see how others (including myself) have solved their run problems with the help of people here.

In the meantime some things for you or your mechanic to do (Short version):

1 Make sure all ignition components are functioning correctly
2 Make sure you have no vacuum leaks in the system
3 Make sure other components and settings are correct as John mentions
4 Get a CIS compatible fuel gauge and post your fuel and control pressures at stated temperatures and tell us the number of your WUR. We can then compare your findings with the specs. Let us know if you or he have done these things.

It may turn out, in fact, that it is your WUR. If so, there are ways to adjust and/or repair it, but you should rule out the other components and items first.

Depending on what is wrong, you can get rebuilt ones, you can do some mods yourself, or you can send these things to places that do WUR repair. Rarly may have one, as he said, and Tony (boyt911sc) probably has some available for testing or for sale.

BTW in my case I had what I called an emerging vacuum leak. A small hole was almost opening up in a metal breather pipe that runs next to the oil cooler. There was just a thin, foil like amount of material there, about to open up completely.

I also had a failed bimetal strip in the WUR, which is very common. I had it replaced. Then I reset the control pressures by adjusting the circular metal plug in the top of the WUR. This gave me the correct control pressures for starting with a richer mix, and running at with a leaner one. You need the fuel gauge to check this.

[boyt911sc]

Originally Posted by NWEXCOP

Anyone have an answer to a problem with a warm up regulator on a 75 Carrera?
Car is new to me, starts and dies until warmed up and after that runs great.
I had my mechanic make a check and the warm up regulator seems to be the problem
and they are not or seldom available,
What is the answer?
Thanks, John

John,

Do you know the Bosch ID number of the WUR you have now in the car? Make sure you have the correct one. I will be more than happy to lend you a rebuilt, tested, and calibrated WUR that you could test in your car. No obligation to purchase. It is a loaner. Send it back to me when you are done.

After you installed the loaner WUR from me and the problem is still there, do not blame the WUR. Your problem is caused by something else. Or send your WUR for free testing and evaluation. Just take care of the shipping cost back to you. PM me if you are interested.

Tony

[JSV798]

As John Walker suggests, I would check the AAR first. It should be open when cold; yours sounds like it might be shut. You need to remove it and check. From memory you'll need a 6mm allen key to get at the bolts. Here's a photo of what one should look like when cold.

[Flojo]

Do a classic Kjet-check according to list/spec first, before throwing parts at your car.

regarding the AAR, every year before season starts, I rinse it in brake cleaner and do a fridge-test. it should be wide open after some time and closing when warming up.

[T77911S]

ask your mech if he checked the cold and warm pressures of the WUR.
then post them

other wise take tony up on his offer and let him check it.

[RarlyL8]

I had my mechanic make a check and the warm up regulator seems to be the problem

Everyone assuming the mechanic doesn't know what he's doing? If so just get a list of what he checked and the readings (such as fuel pressures) that he made.

[boyt911sc]

Originally Posted by T77911S

ask your mech if he checked the cold and warm pressures of the WUR.
then post them

other wise take tony up on his offer and let him check it.

Ty,

I got a call from the OP late last night and informed me that the mechanic did check the CCP and WCP. The mechanic knows CIS and his diagnosis pointed to an out of spec WUR.

I am interested to know if they have the correct WUR and waiting for that information. Stay tuned.

Tony

[NWEXCOP]

Sorry for the delay, I was blocked out of the Forum for unknown reasons.
The numbers on my WUR are 0-438-140-148. My mechanic in testing tells me the reading went direct to 40PSI when the car is attempting to start.
I appreciate all of the information received. My car is a 1975 Carrera vin 9115400019, from the Factory July 74.
I am also looking for anyone that has an early Carrera, since mine has some features that are
somewhat different than my old 75. Like an RS spoiler.

[boyt911sc]

Originally Posted by NWEXCOP

Sorry for the delay, I was blocked out of the Forum for unknown reasons.
The numbers on my WUR are 0-438-140-148. My mechanic in testing tells me the reading went direct to 40PSI when the car is attempting to start.
I appreciate all of the information received. My car is a 1975 Carrera vin 9115400019, from the Factory July 74.
I am also looking for anyone that has an early Carrera, since mine has some features that are
somewhat different than my old 75. Like an RS spoiler.

John,

You have the wrong WUR for your engine. WUR-148 is a Mercedes Benz warm up regulator. You could make this work if your mechanic could calibrate -148 to work as WUR-017 or WUR-033. Your mechanic is not even aware that you got the wrong WUR.

Like I said before, not all good and honest mechanics are familiar with CIS troubleshooting. The WUR-148 does not even look like the WUR’s used in 911 engines. PM me if you are still interested in my WUR loaners. I have a collection of 911 WUR’s including 930’s that Pelicanparts members could avail. No obligation to purchase. Send it back to me after the test unless you want to keep it.

Tony

[pmax]

Originally Posted by NWEXCOP

Sorry for the delay, I was blocked out of the Forum for unknown reasons.
The numbers on my WUR are 0-438-140-148. My mechanic in testing tells me the reading went direct to 40PSI when the car is attempting to start.
I appreciate all of the information received. My car is a 1975 Carrera vin 9115400019, from the Factory July 74.

You can measure the FP yourself with a Bosch K-Jetronic Fuel Pressure Tester



The WUR as the name indicates has a warm up phase where the control pressure changes from cold (enrichment) to warm via a heated bimetallic strip mechanism. The mechanic seems to be saying there was no warmup. Same FI system is in many European makes of that era. All Warmup Regulators | SpecialTauto.com

[47silver]

See Jim Williams web site.
911 CIS Primer - Components

I had a cold start intermittently. The problem was the black points wire had been brushing against the distributor and when cold would short out. When I replaced the points with pertronix and found this problem.
in your case the car operates fine when warm. to me that means that the diaphram, filter and bi-metal element in the WUR are ok because as Jim describes in his CIS primer the conduction from the engine heat affects the Wur and lets the control pressure to increase. This tells me that the WUR that for the most part the wur is ok.

So that leaves the heater. The heater could be faulty but that can be checked with an ohmeter,, i think it should be 30 ohms. ill check mine tomorrow. However even a faulty heater lets the car operate.

[T77911S]

Originally Posted by boyt911sc

Ty,

I got a call from the OP late last night and informed me that the mechanic did check the CCP and WCP. The mechanic knows CIS and his diagnosis pointed to an out of spec WUR.

I am interested to know if they have the correct WUR and waiting for that information. Stay tuned.

Tony

i figured you had it under control and had already been through all that and that everyone would just repeat what you have already done.
just found it a bit odd he still posted the problem with working with you off line,.

[boyt911sc]

Originally Posted by T77911S

i figured you had it under control and had already been through all that and that everyone would just repeat what you have already done.
just found it a bit odd he still posted the problem with working with you off line,.

Ty,

I was not sure the OP had the correct WUR and requested him to inspect the WUR ID number and post the information. Sharing this valuable information will help people to diagnose the problem better. You will notice that people have different ways and perceptions to solve this particular problem and it is not bad because people could learn from each other. Sharing the knowledge is priceless.

The main problem is that the CCP is the same as the WCP as what the mechanic discovered. The mechanic diagnosed a faulty WUR and I completely agree with his finding. After installing a CIS pressure gauge kit, it would take less than a minute to locate the culprit.

Tony