Cis pressure test results

[Wew]

Hi all,

My journey is documented on this forum, althought not as organized as others I plan on putting everything together. But first things first. Before reveling in the glory I like to grind and learn . So hear I am took the big plung and did the cis pressure test. Not bad for all of you out there looking for other things to do.
All prep was done including car sitting over night. Hot day outside up onto the 90's.

System pressure: 4.7 bars or 68 psi

Cold control pressure: .8 bar.

Warm control pressure: .8 bar 14 seconds.

Residual pressure: 30 psi 4 minutes
20 psi 8 minutes
No change after another 10 minutes


What's next?

[Wew]

1978 911 sc Cali targa

[tirwin]

Wew,

Your warm control pressure doesn't look right. Are you sure it is .8 bar? It should be more like 3.8. And 14s is too fast. It should take much longer than that. Report back. If that really is correct then your warm control pressure is far too low.

The next thing you should do is hook up a multimeter and take a resistance reading of the terminals on the WUR.

On a '78 WUR your model number should end in 045 and it should be on the top. Can you verify this is the correct number?

[tirwin]

Can you describe your symptoms? Or provide a link to your other posts on your problem?

[ossiblue]

Originally Posted by Wew

Hi all,

My journey is documented on this forum, althought not as organized as others I plan on putting everything together. But first things first. Before reveling in the glory I like to grind and learn . So hear I am took the big plung and did the cis pressure test. Not bad for all of you out there looking for other things to do.
All prep was done including car sitting over night. Hot day outside up onto the 90's.

System pressure: 4.7 bars or 68 psi

Cold control pressure: .8 bar.

Warm control pressure: .8 bar 14 seconds.

Residual pressure: 30 psi 4 minutes
20 psi 8 minutes
No change after another 10 minutes


What's next?

I don't think your reading for warm control is accurate as, already posted by tirwin, it is too low and the time allowed is too short. Warm control should be ~3.5 bars. If you only checked warm control by applying current to the wur, it's possible the element is bad.

Are you sure current was going to the wur prior to the warm control test? Tell us how you conducted the warm control test. Do a test for power to the wur and report back. If you have power, let the wur warm for a longer period, test the warm pressure, and report back.

It would also be nice to know what symptoms you are troubleshooting as well.

[Wew]

I will check power to wur when I get home from the salt mine. Wur plug itself tested 30 ohms.
The wur that is on it is incorrect. 089. Should be 045. In the process of resolving.
Breakthrough
Thanks for all the help and input.
Does anyone know where the other end of the wur electric plug is supped to go or be. Maybe something is loose.

[Wew]

P.s. I wii retest warm control pressure this evening as well and report back.
Thanks again.

[timmy2]

There should be constant power on the wire supplying the WUR when the key is in the run position. So, when you are testing the pressures, just leave the pump running in bypass with the ignition on ( jumpered pump relay) for 5 or more minutes with the WUR plugged in. The pressure should climb to around 3.5 bar.

[tirwin]

If you do the test again and you don't see the warm control pressure increase, that would be suspect. If I remember right, I believe the WUR, the thermo-time switch and the AAR are energized on the same circuit so another thing to check for is to make sure all 3 are getting power. But before you do that, make sure you did the warm control pressure test right.

[Wew]

Did warm control pressure test as described. I literally got almost 0. Just a scoatch above. 5 minutes later same result. Wur has 30 ohms. Electric housing to wur tested and reads 14 volts although the sleeve around near the plug housing is torn open exposing the inner insulated wire. I do have to twist it around to get it to snap into the wur so can't confirm if it is shorting at some point when I go to click it in.
Once I turned off key pressure jumped write up to 2 bars...
What gives?
I must be doing something wrong right?
Please advise.
Thanks

Gary

[timmy2]

So you no longer get a cold control pressure of 0.8 bar?
All you are doing is checking the cold control pressure with the WUR plugged in. It should rise over time. Maybe you put your WUR together wrong?

[Wew]

First image of fuel pressure took all of 30 seconds to get there and then didn't budge.

Left on for almost 6 minutes.

Next photo is of pressure gauge after on turn off key.

[timmy2]

Looks like the WUR is just staying in cold start mode and not adjusting at all. Then when you turn it off you have residual pressure. Swap it out with the right one for your car that is working. 045 model.

[Wew]

Retested.
System pressure is 68 or 4.7 bars
Cold control is barely above the first mark on the pressure gauge. Maybe even slightly lower than the photo above. 2 psi maybe.

Basically no change.

Wur was assembled incorrectly I put it Bach with springs on sombrero rather than over the nut.
My breakthrough thread has images as well.

Thanks for the help,

Gary

[Wew]

Yep. Thanks. That's the plan I am sending it off on monday

[Wew]

Black one connected to wur. White one has been laying in compartment unattached since purchased. Don't know if this adds to the puzzle or just more confusion. I think the white one may have plugged into distributor via green plug that is not present.
Two wires coming directly off and heading right to ignition system.

[timmy2]

Normally it is the grey/white one supplying the WUR, does it have 12 volts with ignition on?
If the black one was for the ignition it may not have any current/ampere capability to supply the WUR.
Try again with the white connector if it has switched power.

[tirwin]

Normally it is the grey/white one supplying the WUR, does it have 12 volts with ignition on?

If the black one was for the ignition it may not have any current/ampere capability to supply the WUR.

Try again with the white connector if it has switched power.

+1

The whiteish grey one is what normally connects to the WUR.

The spring normally sits in the sombrero.

I think you're going to have to get the correct WUR for your car before you can go much further. This one is clearly not increasing the fuel pressure correctly. I would go ahead and check the TTV for the cold start valve (injector) and the AAR to make sure they are getting power too. If they are not then something in your wiring harness is suspect.

[Wew]

Dennis,
You are the man. I have a porsche man crush on you.

Unbelievable. Switched the wires and bingo warm control pressure starts to climb.

Warm control pressure

2.5. Bars. 1.5 mins.
3.0. Bars. 2 mins
3.2 Bars. 3 mins
3.5. Bars. 4. Mins
3.65. Bars. 5 mins

What does this all mean.

Thank for what's next or do I drive it now?

P.s. Dennis you helped me with my msd wiring last year and you called that one right too.

Thank

[Wew]

And you too tony.
Now I try to turn it overand it seems to be vapor locked. Another thing to look into.... I will pm you Monday