CIS Pressure problem

[davis911s]

I borrowed a CIS tester and used this site
http://members.rennlist.com/jimwms/CIS/Testing/wur_specs.html

77 2.7 CIS engine

Cold pressure 1.6bar (should be 0.8) valve closed

System pressure (valve open) would only go up to about 0.7 when I was holding the pump on. It would drop right away to 0.1 if I let off the pump.

When I connected the electrical no change

I also noted that after about 10-15 attempts I could see wetness around 2 or 3 injectors . Leaking injector o ring, is this due to the number of attempts or real bad o rings?

The WUR I am using was taken off a working only 6 weeks ago and has not been used?

To get the fuel pump to turn on I am leaving the key "on" and pushing up on the lever inside the airbox assy

Ideas?

[Johnb911]

Correct me if I'm wrong but I would say that your motor is really full of fuel by now.

[davis911s]

You are right.

Pulled the #3 injector out and it was like a lake it there.

#3 seems to be the worst one

[davis911s]

I took the #1 and #3 injectors out and put them in a glass jar.

With those two in the jar the findings change

Cold pressure is perfect .8 bar
system pressure goes to 4.5 bar with the fuel pump on then drops to 2 bar when pump turns off.

But it makes no difference when I plugged the electrical back into the WUR

I have 12V at the electrical into the WUR when the pump is on

[boyt911sc]

Originally Posted by davis911s

I borrowed a CIS tester and used this site
http://members.rennlist.com/jimwms/CIS/Testing/wur_specs.html

77 2.7 CIS engine

Cold pressure 1.6bar (should be 0.8) valve closed

System pressure (valve open) would only go up to about 0.7 when I was holding the pump on. It would drop right away to 0.1 if I let off the pump.

When I connected the electrical no change

I also noted that after about 10-15 attempts I could see wetness around 2 or 3 injectors . Leaking injector o ring, is this due to the number of attempts or real bad o rings?

The WUR I am using was taken off a working only 6 weeks ago and has not been used?

To get the fuel pump to turn on I am leaving the key "on" and pushing up on the lever inside the airbox assy

Ideas?

Shaun,

You are not doing the proper way/method to check your control and system pressures. By lifting the air flow sensor (ignition switch ON), you're allowing the fuel injectors to deliver fuel unnecessarily to a non-running engine which will cause flooding in the chambers. Use a suitable jumper with in-line fuse and jump-start the FP by connecting terminals #87A & #30 (FP relay socket).

This method will prevent the delivery of fuel in the combustion chambers during your tests. There are numerous threads and discussions about the subject. If you still have some doubts doing the test, simply ask and there will be plenty of help available from the members.

Bentley SC manual has some pictures illustrating the correct position of the CIS fuel pressure gauge valve. Control pressure ---open valve; system pressure---closed valve. The exact opposite of what you did. Keep us posted and will guide you all the way.

Tony

[davis911s]

Tony THANK YOU . Sorry I read until 3AM last night and somehow missed the jumper cable. Damn that will be a lot of fuel sitting in the engine. Will it harm it, how should I "drain" it? Would letting it sit for a day work?

I don't think it would be a good idea to start it like that

I was thinking the ball valve is CLOSED when it is perpendicular and OPEN when it is parallel.

I will do the jumper cable from now on,

Sorry

Shawn

[Johnb911]

I would also take out the plugs and turn the motor over by hand to get that fuel out of there.

[boyt911sc]

Shawn,

Depending how much gasoline has been delivered into the cylinders and amount that seeped throught the rings, your engine oil's integrity might have been compromised. Oil is cheap compared to an engine rebuild. Go check and inspect your oil and make the final decision what to do. Good luck.

Tony

[davis911s]

Will do. Needs an oil change anyway. Oil LOOKS OK, but I would like to get this running before I do the oil change, would that be ok?

I took out the plugs and turned engine over got rid of gas in cylinders

Retested using the FP relay

1.1 bar (a liitle high?)
4.8 bar

no change when I plugged in the electrical connector to wur?

[Paulporsche]

@ 15C your ccp should be about .9 to 1.35 bar. Your warm cp should be 2.7 to 3.1. You have the vac assisted WUR, right? 4.8 FP is OK.

[davis911s]

MORE PROBLEMS

Paul. YES I have a vacuum controlled WUR.

Problem keeps getting worst. I thought since I had a complete set that was from a known working car I would save myself some time and swap the known good parts over. Didn't work.

I swapped over the fuel distributor and the throttle body- since these both came from the running car I thought they would still be set up. Put everything in....no start I was able to get it to start by lifting the air flow sensor for a second thereby putting fuel into the system. But it would start and die right away.

I re-checked the fuel pressures using the gauges;
with the valve closed as soon as I run the fuel pump using the bridged relay the gauge needle wraps ALL THE WAY around the gauge until the stop.

Obviously the system pressure is WAY too high with these "new" parts.

What is going on? I am getting frustrated

I know that just throwing parts on something is NOT the way to fix things but I thought since the "new" parts worked this would be easier.

Also does anyone have the correct vacuum diagram for a 77 CIS? I found the one for a 78 on Jims website. The two I have had different vacuum connectors

This is how I have t right now- Front ports on throttle body- top one to bottom of WUR, bottom one to Thermo time switch and t to dist (plugged). Rear smaller plugs on throttle body plugged. Vacuum control was hooked up the same on both.

PLEASE HELP

[piscator]

Am I confused or missing something ?

Your "system pressure" (with the ball valve closed and using a piece of wire to jump #87A to #30) should be 4.8 bar and your's is 4.8 bar -- that's normal

Your "cold pressure" (with ball valve open) should be around 1.6 bar and yours is 1.6 bar -- that's normal.

What's "getting worse?"

piscator

[kodioneill]

For 12v at your wur the alternator must be charging.

[don gilbert]

have you checked for return line blockage? Ive worked on two cars that were sitting for a few years, and both had a blockage at the return nipple on the tank, just a thought.

[Paulporsche]

[QUOTE=davis911s;4734532]MORE PROBLEMS




I re-checked the fuel pressures using the gauges;
with the valve closed as soon as I run the fuel pump using the bridged relay the gauge needle wraps ALL THE WAY around the gauge until the stop.



What is going on? I am getting frustrated

Make sure you doing the testing correctly. Ricks911s has a thread w/ videos or check one of my recent threads.

I know that just throwing parts on something is NOT the way to fix things but I thought since the "new" parts worked this would be easier.

"Throwing Parts" really refers just to buying a lot of new parts and putting them on until the problem stops. In your case, temporarilly putting some good parts on from a running car seems a good way to go about it. It is pointing out yopu may have some other issues, eg testing procedure, blocked fuel lines or vac leaks.

Also does anyone have the correct vacuum diagram for a 77 CIS? I found the one for a 78 on Jims website. The two I have had different vacuum connectors

Try page 46 of the 74-77 portion of the "New Parts Diagrams" PET on this site.

[unclebilly]

Check your fuel pump pressure and as mentioned above the return line. You should be able to blow into your return line and have it bubble at the tank. You shouldn't be able to wrap the gauge if the fuel has a place to go.

That stuff ran perfectly on my car.

[Jim Williams]

Originally Posted by davis911s

MORE PROBLEMS


I re-checked the fuel pressures using the gauges;
with the valve closed as soon as I run the fuel pump using the bridged relay the gauge needle wraps ALL THE WAY around the gauge until the stop.

Obviously the system pressure is WAY too high with these "new" parts.

What is going on? I am getting frustrated

I know that just throwing parts on something is NOT the way to fix things but I thought since the "new" parts worked this would be easier.

Also does anyone have the correct vacuum diagram for a 77 CIS? I found the one for a 78 on Jims website. The two I have had different vacuum connectors



PLEASE HELP

Shawn,

Two things can cause the system pressure to be way too high: one is the pressure regulator in the fuel distributor can be mis-adjusted or frozen closed; the second is a blockage in the return line that goes from the fuel distributor back to the fuel tank.

The regulator in the FD is a bleed valve/spring arrangement with shims under the spring to regulate the pressure to roughly 5.0 Bar. If the regulator is doing it's job, then the excess fuel must be free to flow back to the fuel tank for the FD regulator to be able to work. So to check the return to the tank, substitute a fuel line in place of the tank return, into a coffee can or similar. If you get flow to the can, then the fuel line to the tank may be plugged. If no flow, and gauge registers the high pressure, the blockage is in the FD.

[davis911s]

Originally Posted by piscator

Am I confused or missing something ?

Your "system pressure" (with the ball valve closed and using a piece of wire to jump #87A to #30) should be 4.8 bar and your's is 4.8 bar -- that's normal

Your "cold pressure" (with ball valve open) should be around 1.6 bar and yours is 1.6 bar -- that's normal.

What's "getting worse?"

piscator

Sorry that is what is confusing

I had the proper pressures with my "old" parts. But I could not adjust the mixture and idle to get the car to idle under 2500. Without it stalling or running it really rich.

So I changed out the fuel distributor and throttle body with ones that were removed from a known working car. Now I have these new pressure problems

Originally Posted by don gilbert

have you checked for return line blockage? Ive worked on two cars that were sitting for a few years, and both had a blockage at the return nipple on the tank, just a thought.

Don

I have not checked, but I did NOT swap it, and the pressures were good with the "old" parts.

Originally Posted by Paulporsche

Make sure you doing the testing correctly. Ricks911s has a thread w/ videos or check one of my recent threads.

Will do, but the testing was the same as I did in the morning with the old stuff. It was late last night, maybe I missed something? I sure hope so.

Originally Posted by Paulporsche

"Throwing Parts" really refers just to buying a lot of new parts and putting them on until the problem stops. In your case, temporarilly putting some good parts on from a running car seems a good way to go about it. It is pointing out yopu may have some other issues, eg testing procedure, blocked fuel lines or vac leaks.

Thanks, Fuel lines were not changed so can't be blocked.

Originally Posted by unclebilly

Check your fuel pump pressure and as mentioned above the return line. You should be able to blow into your return line and have it bubble at the tank. You shouldn't be able to wrap the gauge if the fuel has a place to go.

My fuel pump pressure was great in the morning, and was not changed, neither was the return line.

If I blow into it will I hear it in the tank? And just to confirm the fuel return line you are talking about is the 17mm one that comes of the back of the fuel distributor and goes to the tank. There are two back there the one on the left side comes from the fuel filter and the one on the right side is the return?

Originally Posted by unclebilly

That stuff ran perfectly on my car.

I have NO DOUBT in that! That is why this is so confusing to me. I will get this sorted out, I think it will be something small that I somehow missed

Shawn

[davis911s]

Originally Posted by Jim Williams

Shawn,

Two things can cause the system pressure to be way too high: one is the pressure regulator in the fuel distributor can be mis-adjusted or frozen closed; the second is a blockage in the return line that goes from the fuel distributor back to the fuel tank.

The regulator in the FD is a bleed valve/spring arrangement with shims under the spring to regulate the pressure to roughly 5.0 Bar. If the regulator is doing it's job, then the excess fuel must be free to flow back to the fuel tank for the FD regulator to be able to work. So to check the return to the tank, substitute a fuel line in place of the tank return, into a coffee can or similar. If you get flow to the can, then the fuel line to the tank may be plugged. If no flow, and gauge registers the high pressure, the blockage is in the FD.

Checked the return line.
I blew air into the line and could hear it bubbling in the gas tank, it is not clogged

Then I used the spare return line and attached it to the fuel distributor and placed the other end into a jar.

Turned on the fuel pump and there is gas flowing into the jar.

So the excess is leaving the FD and the return line is not blocked.

What else can cause high system pressure? I am really confused

Thanks, and Happy Fathers Day

Shawn

[unclebilly]

Originally Posted by davis911s

My fuel pump pressure was great in the morning, and was not changed, neither was the return line.

If I blow into it will I hear it in the tank? And just to confirm the fuel return line you are talking about is the 17mm one that comes of the back of the fuel distributor and goes to the tank. There are two back there the one on the left side comes from the fuel filter and the one on the right side is the return?



I have NO DOUBT in that! That is why this is so confusing to me. I will get this sorted out, I think it will be something small that I somehow missed

Shawn

This is pretty weird. Is it possible (the fittings are different so it shouldn't be) that you got the return and supply lines mixed up? The check valve in the pump would prevent flow back to the tank.

The return line also goes to the bottom of the tank.

You might think about sending a blast of air down the return line with your air compressor. I wouldn't do much more than 100 psi.

I feel terrible about this, you should have been able to reconnect the lines I disconnected for shipping and put my system on and go. My car ran really well with that system.

Scott.