CIS fuel pressure test

[hellblau82]

So I got my hands on a CIS pressure tester today.
I ran a few tests my first test running the fuel pump with the gauge attached and the WUR not connected showed 2.5-3 bars...when connecting WUR it had no response no increase in pressure as most guides recommend.

I noticed I had a small leak at the fuel pump which I fixed..and retested...and then I got up to 5 bars with the WUR disconnected ..when connecting again no increase..

Does this mean I have a faulty WUR..it was making some squeezing noises I'm leaning towards this being damaged

[boyt911sc]

Originally Posted by hellblau82

So I got my hands on a CIS pressure tester today.
I ran a few tests my first test running the fuel pump with the gauge attached and the WUR not connected showed 2.5-3 bars...when connecting WUR it had no response no increase in pressure as most guides recommend.

I noticed I had a small leak at the fuel pump which I fixed..and retested...and then I got up to 5 bars with the WUR disconnected ..when connecting again no increase..

Does this mean I have a faulty WUR..it was making some squeezing noises I'm leaning towards this being damaged

Good to hear that you have the pressure gauge available now. It is about time to learn and interpret the pressure readings. Take a picture of the pressure gauge kit installed between the FD and WUR. The shut-off valve should be towards or nearer to the WUR not to the FD.

This is the basic test for system, control, and residual fuel pressures:
1). Install the pressure gauge kit between WUR and FD.
2). Run the FP using the FP relay socket terminals #87A & #30. Avoid using the AFS switch as much as possible.
3). Turn the ignition switch @ ON and start the FP.
4). With the valve completely open, you get the control fuel pressure (cold or warm).
With the valve closed (FP running) you get the system fuel pressure.
5). To evaluate the control fuel pressure, plug the electrical connector to the WUR and run the FP for 4 mins. The very instant the FP ran, that's your cold fuel pressure. Closely observe the control pressure build up after 1 min., 2 min., etc. no more than 4 mins. and record these pressure readings at different intervals.
6). Turn off the FP. The pressure gauge reading @ X psi. (Bar) would go up slightly when after you switched off the FP. If you don't experience this pressure change after the switch off, your fuel accumulator is suspect (?).
7). Lastly, record the pressure drop or change (delta) after shutting down the FP @ zero, 10 min., 20 min., 30 min., etc. This would be your residual fuel pressure.

With the help of this pressure gauge, you could test and evaluate your FP, WUR, and FD effectively and avoid the guess-work which you have been doing the past several months. Keep us posted.

Tony

[hellblau82]

Cheers Tony

I'll go through all this tomorrow! And. Get back to you with the results .

[hellblau82]

Still getting 5.5 bar with valve open and closed

[boyt911sc]

Originally Posted by hellblau82

Cheers Tony

I'll go through all this tomorrow! And. Get back to you with the results .

Take your time. Do not rush doing it. What is important is doing it right the first time.

BTW, I will be in Melbourne this spring (March 2016) rather fall Aussie season. I am not taking my golf bag and I could bring some small parts if you would need any. Make a wish list and I will mail them to you at Melbourne.

Australian summer is coming very soon. Let's get this thing running ASAP.

Tony

[ossiblue]

Good that you have Tony on board with this--he knows his stuff through lots of hands-on experience.

From you initial results, no change in system and cold control pressure, the problem is looking to be a blockage in the return path to the tank. This could be a fault with the WUR or a blockage in the return line. The most likely problem is with the WUR as your system pressure is within spec and if the there was no fuel at all returning to the tank, the pressure would likely be closer to 6 bars if you have a stock pump (which I know you don't.)

Regardless of what your initial results appear to be, perform all of the tests Tony has listed and post the results. If your fuel tests confirm the pressure never change from the high value of system pressure, you can begin work in locating the area of obstruction.

[boyt911sc]

Originally Posted by hellblau82

Still getting 5.5 bar with valve open and closed

Kristian,

The picture shows that the shut-off valve is in the closed postion. This setting is used for checking the system fuel pressure. Open position is for control fuel pressure check. Just to make sure we are on the same page, please confirm. I have a mini special test for you to follow.

Tony

[hellblau82]

Originally Posted by ossiblue

Good that you have Tony on board with this--he knows his stuff through lots of hands-on experience.

From you initial results, no change in system and cold control pressure, the problem is looking to be a blockage in the return path to the tank. This could be a fault with the WUR or a blockage in the return line. The most likely problem is with the WUR as your system pressure is within spec and if the there was no fuel at all returning to the tank, the pressure would likely be closer to 6 bars if you have a stock pump (which I know you don't.)

Regardless of what your initial results appear to be, perform all of the tests Tony has listed and post the results. If your fuel tests confirm the pressure never change from the high value of system pressure, you can begin work in locating the area of obstruction.

Ok I'm having a bit of a thought...the return fuel line..when I first received the car was damaged at the fuel pump end.
I had made an attempt to repair it which I don't think is a very good solution.
I have used hose clamps to join it where it was severed so I believe that maybe this could be causing a pressure/fuel starvation issue I thought I could of gotten away with it but it doesn't look like I will.
I will purchase a new return line now and replace it.

[ossiblue]

Originally Posted by hellblau82

Ok I'm having a bit of a thought...the return fuel line..when I first received the car was damaged at the fuel pump end.
I had made an attempt to repair it which I don't think is a very good solution.
I have used hose clamps to join it where it was severed so I believe that maybe this could be causing a pressure/fuel starvation issue I thought I could of gotten away with it but it doesn't look like I will.
I will purchase a new return line now and replace it.

maybe it's an illusion, but the metal part of that line, just before the nut, looks to be flattened and nearly closed off.

[hellblau82]

Yes your right..it has a bit of a fold in it..I assumed that's how the connector was or how it comes ...is this not normal?

[ossiblue]

Originally Posted by hellblau82

Yes your right..it has a bit of a fold in it..I assumed that's how the connector was or how it comes ...is this not normal?

Not normal.

This could be the solution to your entire problem.

[hellblau82]

Could be...I'm doubtful though seeing it ran wel the first few times I turned it over..I'll have a at with it

[ossiblue]

Originally Posted by hellblau82

Could be...I'm doubtful though seeing it ran wel the first few times I turned it over..I'll have a at with it

Think positively!

At least you have a visible flaw that can be addressed and is consistent with your constant system pressure readings. Yes, it ran well for a while and you may have other issues as well, but that connection definitely looks to be crimped which would prevent any significant pressure variations controlled by the WUR. Eliminating that questionable part will narrow the hunt for any other suspects, and may fix the constant system pressure readings you are getting.

[hellblau82]

Originally Posted by ossiblue

Think positively!

At least you have a visible flaw that can be addressed and is consistent with your constant system pressure readings. Yes, it ran well for a while and you may have other issues as well, but that connection definitely looks to be crimped which would prevent any significant pressure variations controlled by the WUR. Eliminating that questionable part will narrow the hunt for any other suspects, and may fix the constant system pressure readings you are getting.

Ok that mod was definately blocked..I've had it off checked he airway which is better now reconnected now only a 0 reading with the valve open and 5 with it closed...does that mean there's still a blockage?

[Bob Kontak]

Originally Posted by hellblau82

Ok that mod was definately blocked..I've had it off checked he airway which is better now reconnected now only a 0 reading with the valve open and 5 with it closed...does that mean there's still a blockage?

0 reading is odd. I think the reading means there is no pressure in the line at all. There would have to be some pressure even if the WUR was just an in and out tube with no restriction applied.

I am not a hydraulic engineer, though.

[hellblau82]

Originally Posted by Bob Kontak

0 reading is odd. I think the reading means there is no pressure in the line at all. There would have to be some pressure even if the WUR was just an in and out tube with no restriction applied.

I am not a hydraulic engineer, though.

Yes very strange

[Bob Kontak]

Originally Posted by hellblau82

Ok that mod was definately blocked..I've had it off checked he airway which is better now reconnected now only a 0 reading with the valve open and 5 with it closed...does that mean there's still a blockage?

0 reading is odd. I think the reading means there is no pressure in the line at all. There would have to be something even if the WUR was just an in and out tube with no restriction applied.

I a not a hydraulic engineer, though.

[ossiblue]

Originally Posted by hellblau82

Yes very strange

Strange, indeed. My first thought would be the accuracy of the gauge set. Do you have confirmation that it is reliable?

I'm with Bob on this one, though my experience is not as extensive as Tony's. Logic tells me that even if the WUR is allowing all fuel to pass through, there would be some pressure buildup that would register on the gauge.

BTW, you PM'd me by mistake, instead of Tony, regarding this issue. I forwarded you PM on to him.

[hellblau82]

Originally Posted by ossiblue

Strange, indeed. My first thought would be the accuracy of the gauge set. Do you have confirmation that it is reliable?

I'm with Bob on this one, though my experience is not as extensive as Tony's. Logic tells me that even if the WUR is allowing all fuel to pass through, there would be some pressure buildup that would register on the gauge.

BTW, you PM'd me by mistake, instead of Tony, regarding this issue. I forwarded you PM on to him.

God this is annoying! Haha I bought the gauge yesterday..I'll do some more tests tonight connect reconnect he gauge..
Other than that it's stumped me for now

[boyt911sc]

Originally Posted by ossiblue

Strange, indeed. My first thought would be the accuracy of the gauge set. Do you have confirmation that it is reliable?

I'm with Bob on this one, though my experience is not as extensive as Tony's. Logic tells me that even if the WUR is allowing all fuel to pass through, there would be some pressure buildup that would register on the gauge.

BTW, you PM'd me by mistake, instead of Tony, regarding this issue. I forwarded you PM on to him.

Larry,

The PM you received was addressed to you and it was not a mistake(?). Thanks for forwarding it. This CIS troubleshooting is taking too long to solve because of the wrong approach to solving this problem. A fuel pressure gauge is a mandatory tool and it took him this long to get one. Anyway, it would be better now that we could get some numbers about the fuel pressure provided he has a good working set.


Kristian,

Do us a favor and run the FP with pressure gauge installed and with the valve OPEN. We like to see the some fuel pressure and get a feel if the gauge you have is working or not.

Disconnect the return line to the fuel tank at the fitting located by the engine. Measure the flow rate (liters per min.) of the fuel going back to the tank. Next, reconnect the return line and make sure it is tight and not leaking. Run again the FP and take note of the following:
a). With FP running and the shut off valve OPEN, what is the pressure reading on the gauge?
b). Close the valve while the FP is running, what is the pressure reading on the gauge?
c). Repeat test 'a' FP running and valve OPEN. But this time pinch the return line (rubber hose) going to the tank and observe the pressure gauge. What pressure reading when the return fuel hose was pinched?

If you could provide some answers (fuel pressure @psi.) to the above tests, we could offer you a better educated answers. Forget all the tests I gave you earlier, just these last three (3) is what I am interested at the moment. Thanks.

Tony