WUR return line

[pmax]

On a side note, the 072 WUR is for an 80.

Was it replaced at some point for your 83 ? What does the Lambda control unit look like, under the seat ?

[BoxsterGT]

Gary-

I could not find a solid one piece steel line, but the earlier CIS models all use Polyamide tube and I make these up all the time.......





I am happy to help, but it's best if we converse directly by email.

len.cummings @ verizon.net but without the spaces.

Len

[boomvang1]

Pmax, it is for sure an 072, I was surprised as well. I will take a look under the seat, what should the unit look like.

Gary

[boomvang1]

Pmax, it is for sure an 072, I was surprised as well. I will take a look under the seat, what should the unit look like.

Gary

[pmax]

To be clear, the 072 should work as well but it's good to establish the baseline, so to speak.

What happened to the return line ?
Where is the leak ? The metal portion is often subject to abuse ... the one in Len's post is above is typical after years of handling ... but seems to hold up.

[boomvang1]

Mine line looks great, problem is I have been chasing a cold start issue ever since I got the car 5 years ago. I did all the checks, vacuum leaks, fuel pressures and electrical connectors. Took it to a highly respected shop and they replaced the cold start valve. The car ran worse than before. I should have sent it back, buy I am a stubborn old man and wanted to prove something or other. Anyway, I have been getting a cold control pressure of almost 5 bar, which seems to point to a blocked return line. So. I tried to blow through it first by lung and them with bike pump. Line would not allow air to enter. I then attempted to remove the line at the fuel distributor end, only got it to turn ¼ turn before encountering stopping, as I was not getting any easier to turn. Most likely the line has fused to the nut and as a result was damaged and is now leaking.

[boyt911sc]

Originally Posted by boomvang1

Mine line looks great, problem is I have been chasing a cold start issue ever since I got the car 5 years ago. I did all the checks, vacuum leaks, fuel pressures and electrical connectors. Took it to a highly respected shop and they replaced the cold start valve. The car ran worse than before. I should have sent it back, buy I am a stubborn old man and wanted to prove something or other. Anyway, I have been getting a cold control pressure of almost 5 bar, which seems to point to a blocked return line. So. I tried to blow through it first by lung and them with bike pump. Line would not allow air to enter. I then attempted to remove the line at the fuel distributor end, only got it to turn ¼ turn before encountering stopping, as I was not getting any easier to turn. Most likely the line has fused to the nut and as a result was damaged and is now leaking.

Boom,

Talking about old and grumpy men, you are not going to fix this CIS problem unless you listen to people with experience. We are talking a couple of minutes test to identify and locate the culprit and you failed to do it. Or refused to accept the suggestions. And this problem is not going away. Good luck.

Tony

[boomvang1]

@boy911sc, not really sure what you mean. I conducted the tests to determine the issue, as described, what else do you suggest I do? I have a cold control pressure of 5 bar, what else can cause that? I really appreciate all the great advice.

[pmax]

Originally Posted by boomvang1

Mine line looks great, problem is I have been chasing a cold start issue ever since I got the car 5 years ago. I did all the checks, vacuum leaks, fuel pressures and electrical connectors. Took it to a highly respected shop and they replaced the cold start valve. The car ran worse than before. I should have sent it back, buy I am a stubborn old man and wanted to prove something or other. Anyway, I have been getting a cold control pressure of almost 5 bar, which seems to point to a blocked return line. So. I tried to blow through it first by lung and them with bike pump. Line would not allow air to enter. I then attempted to remove the line at the fuel distributor end, only got it to turn ¼ turn before encountering stopping, as I was not getting any easier to turn. Most likely the line has fused to the nut and as a result was damaged and is now leaking.

Take your time, don't need to force anything, you're only 2 pages in Replace that busted line with Len's or post a WTB. I'm impressed you could get at the fittings in front of the FD given the limited room there.

The fuel return from your WUR goes thru the fuel distributor as detailed in this post below given it's a later CIS.
https://forums.pelicanparts.com/porsche-911-technical-forum/1159640-fuel-pressure-testing-system-pressure-cold-control-pressure-residual-press-0-a-10.html#post12271194

[boyt911sc]

Originally Posted by boomvang1

Pmax, it is for sure an 072, I was surprised as well. I will take a look under the seat, what should the unit look like.

Gary

Gary,

Very few people know this secret. WUR-072 = WUR-090. They are the same and identical except for the stamped # on them. If you don’t believe me, investigate and inspect every single component and compare. I don’t want to take this secret to the grave.

Tony

[boomvang1]

Great to know, Tony. Would you take a look at my wur, please.

[boyt911sc]

Originally Posted by boomvang1

Great to know, Tony. Would you take a look at my wur, please.

Gary,

Yes. Send your WUR to me less fuel line fittings and include a RSL (return shipping label) preferably a UPS. Schedule it to arrive after my Engine Rebuilding Workshop. I have suspended my CIS activities during the WORKSHOP. Will PM you the address.

Tony

[pmax]

072 and 090 charts are here.

https://forums.pelicanparts.com/porsche-911-technical-forum/758788-cis-troubleshooting-dummies-4.html#post9671930

Squinting a bit, they do look the samel.

[boyt911sc]

Originally Posted by pmax

072 and 090 charts are here.

https://forums.pelicanparts.com/porsche-911-technical-forum/758788-cis-troubleshooting-dummies-4.html#post9671930

Squinting a bit, they do look the samel.

There is a negligible difference between the two (2) charts by 0.05 bar (0.73 psi.). If you plot every data point points for -072 and -090 control pressure charts on the same chart, the difference is negligible. The pressure gauge tools we use is not capable of detecting the pressure difference unless you have precision laboratory equipment to use.

Tony

[boyt911sc]

Originally Posted by boomvang1

@boy911sc, not really sure what you mean. I conducted the tests to determine the issue, as described, what else do you suggest I do? I have a cold control pressure of 5 bar, what else can cause that? I really appreciate all the great advice.

Gary,

Do you have a HF pressure gauge kit tester? I hope not. Keep us posted. Thanks.

Tony

[boyt911sc]

Originally Posted by boomvang1

Great to know, Tony. Would you take a look at my wur, please.

Gary,

Before you send your WUR, could you post a close-up shot of the WUR? I am interested to see the top particularly the area where the plug is located. Thanks.

Tony