YACTT (Yet Another CIS Troubleshooting Thread)...

[allaircooled]

If you don't get the cis gauge figured out, I can let you borrow mine when I get back in town. You might have it done by then though.

[m1sandman]

Thanks Chris... I may have to. The borrowed one that I have doesn't have the right fitting to screw directly into the top of the FD on the 74. If I didn't have to worry about the banjo fitting inside the port headed for the WUR, I would have been able to get readings today!

[m1sandman]

So gents, is there anything else I can be troubleshooting before I get a gauge to read control pressure? I've got new injector seals to be installed, so I can go ahead and do those...

[theFONZ]

You could do the vacuum leak test and order what you need to replace along with the fuel tester.

[m1sandman]

Ok, so I'd like to do some vacuum tests this weekend as was reading this thread:
Finding CIS vacuum leaks - the vacuum cleaner pressure test

It sounds like you can pressurize the system through the exhaust, which would be an easy way of doing it, but is there any concern about blowing anything nasty back into the engine? Or should I just pull the airbox and do it from the top?

Thanks!

[allaircooled]

I am going to perform this test too but I was going to try to do it from the top. I have no experience yet with a vacuum leak test so I don't know if one way is better than the other though.

[m1sandman]

Hey Chris! You back in town yet? Send me a PM with some contact info and maybe we could meet up this weekend...

[m1sandman]

Ok CIS Fuel Pressure experts -- what kind of adapter do i need (and where can I get it) to adapt the hose the normally screws onto the outlet of the FD to now go between the FD fitting with the Banjo fitting and the FD itself? Anyone got any specs? Does the house unscrew from the FD fitting, then that fitting unscrew (with the banjo in place) from the top of the FD? is it male going into the top of the FD?

I was able to replace the injector seals and straighten the Pop-off plate in my airbox this weekend, which I was hoping would help a little, but I think there is still too much control pressure for it to start and run.

Thanks!

[boyt911sc]

Originally Posted by m1sandman

Ok CIS Fuel Pressure experts -- what kind of adapter do i need (and where can I get it) to adapt the hose the normally screws onto the outlet of the FD to now go between the FD fitting with the Banjo fitting and the FD itself? Anyone got any specs? Does the house unscrew from the FD fitting, then that fitting unscrew (with the banjo in place) from the top of the FD? is it male going into the top of the FD?

I was able to replace the injector seals and straighten the Pop-off plate in my airbox this weekend, which I was hoping would help a little, but I think there is still too much control pressure for it to start and run.

Thanks!

Break the fuel line fitting at the WUR. I'm away from home traveling and if my memory serves me right, the thread should be 10 mm x 1.25 (?). Stay away from the FD and try to do your work at the WUR for fuel pressure tests.

Tony

[ossiblue]

Originally Posted by boyt911sc

Break the fuel line fitting at the WUR. I'm away from home traveling and if my memory serves me right, the thread should be 10 mm x 1.25 (?). Stay away from the FD and try to do your work at the WUR for fuel pressure tests.

Tony

Tony, remember he has a 74 with the throttle positioner and fuel hose coming from the FD which needs to be connected on the wur side of the gauge set.

[prebordao]

Originally Posted by boyt911sc

Break the fuel line fitting at the WUR. I'm away from home traveling and if my memory serves me right, the thread should be 10 mm x 1.25 (?). Stay away from the FD and try to do your work at the WUR for fuel pressure tests.

Tony

The line that goes to the WUR is a nylon one. try not to mess with it as they're a pain to refit.

[prebordao]

m1sandman I guess your car is lime green ?

Mine is also, and from 74 !

Some pics from a regularity rally I just entered. The funny wheel at the front is a spare from a 944.

[m1sandman]

Hey Ossiblue, do you have any idea what kind of adapter I need?

Pjr, I'm liking the cookie cutters, nice to see one mooooving!

[ossiblue]

Originally Posted by m1sandman

Hey Ossiblue, do you have any idea what kind of adapter I need?

Pjr, I'm liking the cookie cutters, nice to see one mooooving!

If you can post a pic of where the line to the wur connects to your FD, that would help my memory as I haven't had that set up for a long while. IIRC, you can remove the fitting that screws into the FD and holds the banjo fitting as well as the line to the wur and screw it into the outlet end of the gauge set--you may need an adapter for this. You will need a fitting that will connnect the inlet side of your gauge set to the outlet of the FD, where the combo fitting was removed. The line from the wur then connects back to the fitting you have screwed into the outlet of the gauge set.

[m1sandman]

Hey Ossiblue,
Yep, those are the adapters i need to figure out. Here's a picture of the top of my FD:

[ossiblue]

Originally Posted by m1sandman

Hey Ossiblue,
Yep, those are the adapters i need to figure out. Here's a picture of the top of my FD:

Thanks for the pic.

(From the FD housing, outward) It looks like there is a lug that tightens the fitting into the FD housing, correct? Then, you see the banjo fitting, then a lug for an adapter to which the line to the wur is connected. The lug on the adapter appears to snug the banjo fitting in place. Is this correct?

Bottom line, the way the lines are assembled in the picture needs to be connected in the same way to the outlet side of the gauge set, and connect the inlet side of the gauge set directly to the FD housing. Once you disassemble the connections shown, you should be able to figure out what adapters or fittings you will need. It shouldn't be too complicated.

[m1sandman]

Ok, I pulled the banjo bolt off the top of the WUR and have confirmed that I need M8x1.0 adapters (male and female) to be able to test. I'm uploading a picture of my WUR per request from Tony as well.

Chris, if you are still on the thread, would love to see if you have those adapters in your test kit and if so, would you consider loaning it or helping me test it?

Thanks to all!

[boyt911sc]

Originally Posted by m1sandman

Ok, I pulled the banjo bolt off the top of the WUR and have confirmed that I need M8x1.0 adapters (male and female) to be able to test. I'm uploading a picture of my WUR per request from Tony as well.

Chris, if you are still on the thread, would love to see if you have those adapters in your test kit and if so, would you consider loaning it or helping me test it?

Thanks to all!

sandman,

What are you trying to do? Check your fuel pressures with a fuel pressure gauge? Why do you need an adaptor (8 mm x 1.0)? This how I would do it:

1). Hook up the pressure gauge at either at the FD or WUR in series. Run the FP and with valve open.........you get the control fuel pressure reading. Please take note that this cold fuel pressure reading is directly controlled by the WUR and TPR (throttle pressure regulator with 3 settings). Select idle setting. This is how you check your control fuel pressure. This configuration is completely different from the CIS without the TPR (lever).

If you are getting a cold cold fuel pressure greater than the warm control pressure, there is flow restriction in the fuel return line/s. When the flow restriction is severe or totally blocked, the control fuel pressure would be greater than the system pressure.

2). For the system fuel pressure: You need to isolate the WUR and the TPR to get the pressure reading. Closing the valve to obtain the system pressure is correct for the later CIS engine without TPR.

Jim Sim's has a simple solution to this problem without using an adaptor (clever idea) by pinching close the return line from the TPR. The problem I find with this set-up even if it works is the inability to confirm or verify the fuel flow is completely stopped. A small leak is not that critical for this measurement.

Another method with I personally prefer is to remove the banjo fitting from the FD going to TPR. This would need an adaptor and plugged the banjo just in case there is fuel blockage at the return line. With the valve closed, both the WUR and TPR (disconnected) are isolated. No guessing!!!!

Tony

[m1sandman]

Hey Tony,
See my answers in line below. I'll call you later in the day if I get a chance, I appreciate that offer.

Originally Posted by boyt911sc

sandman,

What are you trying to do? Check your fuel pressures with a fuel pressure gauge? Why do you need an adaptor (8 mm x 1.0)?

Based on what Ossiblue was saying above, I thought I needed to put my pressure gauge between the top of the FD and the fitting that goes to the WUR including the banjo bolt that goes to the TPR. I pulled that fitting and checked the size and thread pitch and it's an M8x1.0, which I don't have, so I figured I would need a female adapter for the WUR/TPR fitting to screw into and a male adapter to screw into the top of the FD.

Originally Posted by boyt911sc

This how I would do it:

1). Hook up the pressure gauge at either at the FD or WUR in series. Run the FP and with valve open.........you get the control fuel pressure reading. Please take note that this cold fuel pressure reading is directly controlled by the WUR and TPR (throttle pressure regulator with 3 settings). Select idle setting. This is how you check your control fuel pressure. This configuration is completely different from the CIS without the TPR (lever).

If you are getting a cold cold fuel pressure greater than the warm control pressure, there is flow restriction in the fuel return line/s. When the flow restriction is severe or totally blocked, the control fuel pressure would be greater than the system pressure.

I have done this... its the only test I have successfully done (the cold control pressure at least) and measured 70psi, which as I understand is 20psi higher than what it should be. I have not gotten a warm control pressure -- which i think is what you wanted in post #11. I will attempt to provide that shortly.

As an aside, the factory spec I'm working from is based on a post by John Walker on rennlist here which specify 4.8-5.2 BAR, SYSTEM PRESS, AND 3.4-3.8 BAR, CONTROL PRESS. ROUGHLY 70-76#, AND 50-56# RESPECTIVELY, but I can dig through my brothers factory shop manual and track them down if you guys think we need more confirmation.

Originally Posted by boyt911sc

2). For the system fuel pressure: You need to isolate the WUR and the TPR to get the pressure reading. Closing the valve to obtain the system pressure is correct for the later CIS engine without TPR.

Jim Sim's has a simple solution to this problem without using an adaptor (clever idea) by pinching close the return line from the TPR. The problem I find with this set-up even if it works is the inability to confirm or verify the fuel flow is completely stopped. A small leak is not that critical for this measurement.

Another method with I personally prefer is to remove the banjo fitting from the FD going to TPR. This would need an adaptor and plugged the banjo just in case there is fuel blockage at the return line. With the valve closed, both the WUR and TPR (disconnected) are isolated. No guessing!!!!

So in this description, it sounds like I don't need the M8x1.0 adapters to get the system pressure (if I'm understanding this correctly)... all I would need to do it pinch off the return line from the TPR and close the valve on the pressure tester (which is installed on the WUR side of the gauge), correct? that would isolate the FD as no fuel could then flow to the WUR or the TPR. Am I understanding it correctly?

Thanks for all your help!
Steve

[m1sandman]

OK, I have just run the tests as described below, 80 degrees ambient temp, cold engine (with the results):

Cold Control Pressure (tester between FD and WUR, valve open):
72 psi

Warm Control Pressure (same as above, power to WUR):
30 sec - 74psi
60 sec - 74psi
90 sec - 74psi
120 sec - 74psi

System Pressure (tester between FD and WUR, valve CLOSED, TPR return line pinched close):
78psi

Steve