I dont have access to an AFR, but I will attempt to stop by some garages and see if I can get it tested. I did suspect it to be running rich but didnt want to mess with the air/fuel screw prior to checking the fuel pressures. How do I go about testing the WUR pressure with vacuum applied? Would it be lines connected with engine running? Thanks for the help. Hopefully this will get figured out.

Lou

Just use something like this to apply to the WUR.

https://www.sciencecompany.com/Asset...nc6678n-lg.jpg

You can use the minivac Pmax shows or start the engine with the pressure gauge installed and all hoses connected letting engine provide vacuum. Advantage of starting the engine: it allows you to watch both that the ttv is working and the vacuum function of the wur. Minor Disadvantage is need to start the engine. Since your engine runs, not a big issue.

WUR-045 tests......
 

Lou,

This how you test and calibrate your control fuel pressures: Test run the FP by bridging terminals #87a & #30 ignition switch @ ON (not start). Measure the following:

a). CCP with and without vacuum, electrical plug disconnected.
b). WCP with and without vacuum, electrical plug connected (4~5 mins. max).

A 30 sec. intervals reading will give you a better understanding how the cold control fuel pressures go from CCP to WCP over a period of time. Use a hand held Mity Vac and pressure gauge for the test and record these values. Compare your data to the Control Pressure Chart (-045).

A closer look at the picture of the WUR shows the “plug” is already way too low. And a good indication that the WUR was experiencing out of spec cold control fuel pressure. And had been adjusted or re-calibrated. Normally the plug is about 1-mm recessed. Keep us posted.

Tony

Here are the Control Fuel Pressures with 16 HG of vacuum:

1. Cold Control Fuel Pressure with Vacuum (Electrical WUR Plug Disconnected): 2.0 Bar

2. Warm Control Fuel Pressure with Vacuum (Electrical WUR Plug Connected):

30 seconds: 2.3 Bar
1:00 minute: 2.7 Bar
(1:30) 3.0 Bar
(2:00) 3.2 Bar
(2:30) 3.2 Bar
(3:00) 3.2 Bar
(3:30) 3.2 Bar
(4:00) 3.2 Bar

The Warm Control Fuel Pressure settings were also confirmed with the engine running vacuum line reconnected.

I was at 2.8 Bar with Vacuum line removed, Electrical WUR Plug Connected, car cold.

Here are the control fuel pressures without vacuum:

System Fuel Pressure (Valve Closed on tester) (car cold) (WUR electrical connector disconnected): 4.9 bar

Cold Control Fuel Pressure (no vacuum) (car cold) (WUR electrical connector Disconnected): 1.7 bar

Warm Control Fuel Pressure (no vacuum) (WUR Electrical Connector Connected) 4 minute test with fuel pump running:

Initial: 1.7 Bar
2 minutes: 1.7 bar
2:30 (2.1 bar)
3 minutes: (2.4 bar)
3:30 (2.65 bar)
4 minutes (2.75 bar)


Thoughts??

Thanks

One other thing: with the fuel pressure gauge in place I started the car up in order to confirm the previous numbers that I got with the vacuum gauge. The odd thing was the car started up just fine with no drop in rpms. It started at 1700rpms and evenutally tapered off to 950rpms. I wonder if it was just coincidence or something else with the gauge in place.

Repeat the test........
 

Lou,

Repeat the above tests monitoring @ 30 sec. intervals the control fuel pressures and engine RPM. Connect the WUR electrical plug and read as quickly as possible the pressure gauge and tachometer for 0 sec. (initial) data. The first point is not critical. Just continue to monitor the pressure gauge and tachometer from start to 4 mins. at 30 sec. intervals. We are interested to see the trend so approximate readings should be sufficient. It would be helpful to have a second person watching the tachometer and the other watching the pressure gauge. Thanks.

Tony

Tony,

I am assuming you want that done when the engine is cold?

Thanks

Cold start........
 

Lou,

Yes. You were having a cold start problem based from your posts. So this test must be done with a cold engine. And tomorrow would be a good day to do the test. The colder the ambient temperature the better. I like to find what out is causing the RPM to go up and down.

Since you are local, PM me your address and I will ship a WUR-045 for you to test. And compare the engine behavior with the replacement WUR. I would like to eliminate the WUR as the culprit. Thanks.

Tony

OK. Thanks Tony. Ill email it to you.

Tony here it is: Cold Start (Bar and RPMS every thirty seconds)

Initial: 1.7 Bar (1800rpms) Fuel Pressure remained the same while RPMS dipped from the 1800 initial to 1000rpms then back up to 1800rpms. All within approximately 10 seconds.

30 seconds: 2.4 Bar (1800rpms)
1:00 (3.0 Bar, 1800 rpms)
1:30 (3.2 Bar, 1200 rpms)
2:00 (3.2 Bar, 1000 rpms)
2:30 (3.2 Bar, 1000 rpms)
3:00 (3.2 Bar, 950 rpms)
3:30 (3.2 Bar, 950 rpms)
4:00 (3.2 Bar, 950 rpms)


Question: Yesterday when I bypassed the fuel pump relay to check warm control pressures the electrical connector was connected heating the element up inside the WUR for approximately 4 minutes. Once I recorded the pressures I plugged the fuel pump relay back in the fuse location and started the car, there was no initial rpm drop which I thought was weird. My question is could there be something with the heating element inside the WUR already being heated that helped it start not causing the initial rpm drop?

Thanks

Test results............
 

Lou,

Please update this thread with your test results after using a replacement WUR-045. Thanks.

Tony

Update: Tony (Boyt911sc) was nice enough to mail me out a matching warm up regulator to test to see if mine was the issue. Sadly, it did not work. The car with Tony's WUR still had the same cold start ( firing right up with a 1800rpm idle then quickly droping to 600rpm for a few seconds then climbing back up to 1800 eventually settling down to 950rpm). Since I tested the AAR a year ago I decided to pull it to confirm its ohms (17.5) and function and everything tested fine. The thermo time switch and cold start valve were tested and both seem good. Whats your guys thoughts on the AAV (gold saucer back right side of engine)? Could that cause the cold start drop in rpms?

Thanks,

Lou

That confirms what SkiVT already told you that your WUR is not materially out of spec.

Fuel mixture readings.........
 

Lou,

Double check that your engine does not have significant vacuum leak. Perform a smoke test. Then find a shop with a gas analyzer and have your exhaust measured with a totally warmed engine. I suspect you have a rather RICH setting. But we don’t know that as a fact. So have it tested. And keep us posted.

Tony

Lou

The other thing that impacts the first 30 seconds is the TTV. The vacuum line from the wur to TTV has to connect on the TTV on the outer male connector (see diagram posted earlier), not the middle male connector. Also, the TTV has to be in working order. When all that is true, the TTV holds off vacuum for 30 seconds or so at cold start. This keeps the WUR at the lower w/o vacuum pressure, then lets it jump at around 30 seconds, the the w/vacuum values. In other words, it keeps it richer for that time period which would be opposite of Tony’s suspicion. You can watch this happen on the pressure gauge from cold start if you actually start the engine with the guage connected. I bring this up only because of my personal experience with my vacuum lines connected to the TTV backwards and having a similar rpm drop symptom 2 years ago.

There are not a lot of other things that are time dependent in the first 30 seconds, that you haven't already confirmed, other than the TTV. If this also checks out, the possible vacuum leaks and mixture values Tony is pointing to are the likely culprits. I am not as familiar with the AAV function but have read it's very stout and only functions at start, like the timing of the CSV.

I pulled the TTV to test and here is what I got using a vacuum gauge:

Room (garage) temperature: center connector on Thermo valve holds vacuum/outer connector does not. Also cant blow through it. Indicating it is closed.

Heated up in oven to 100 degrees: neither the center connector on thermo valve or outer connector hold vacuum. I can blow through it. Indicating valve is open.

Next test is to ensure I'm getting 12v from wires to Thermo valve and to test thermo valve with 12v applied.

SkiVt: So far when doing my pressure testing I never saw that rise like in your video.

http://forums.pelicanparts.com/uploa...1570975654.jpg

http://forums.pelicanparts.com/uploa...1570975654.jpg

Lines seem to be routed correctly. Thoughts?

Thanks again

TTV test results.........
 

Take a look:

http://forums.pelicanparts.com/porsche-911-technical-forum/775313-ttv-test-results.html

Tony

Tony,

Got it. Ive been following that post for these test. Thanks for doing those test. Your post have helped me a lot. I will be testing with 12v later today.

Lou

The vacuum line to the TTV looks correct. Assuming the line from the TTV ends up in the correct spot on the throttle area you should have vacuum.

Your pressure testing without starting the engine would not jump like the video with vacuum applied directly to the wur, if that is what you are asking/thinking. The video was with gauges connected and engine started. When the engine starts and the TTV is working correctly, your CCP should be the value you have recorded with no vacuum applied. If the TTV is not working, you will have immediate vacuum so your CCP should be the amt you recorded when vacuum was added with the mini-vac. The pressure will then rise from either of those start points as the WUR warms. If you are getting power to the TTV and it tests fine with the vacuum, then when you start the engine with the gauges attached you should see that lower no-vacuum CCP and then a bit of a jump when the TTV opens 10-30 seconds later as vacuum increases the pressure. If you see a CCP that matches your w/vacuum recording, you have a problem.