CIS Troubleshooting for Dummies

[flyboy182]

here is a pic of the "rebuilt" WUR that the shop installed just before I purchased the car. I just removed it. Note the marks on the pressed in fitting. Seems that in an earlier life the thing had been pounded on...perhaps why the pressures are both now too low. Short of trying to have that plug pushed back up, I am back to my question about taking it apart and trying to adjust the bi-metallic bar.

[boyt911sc]

Originally Posted by flyboy182

here is a pic of the "rebuilt" WUR that the shop installed just before I purchased the car. I just removed it. Note the marks on the pressed in fitting. Seems that in an earlier life the thing had been pounded on...perhaps why the pressures are both now too low. Short of trying to have that plug pushed back up, I am back to my question about taking it apart and trying to adjust the bi-metallic bar.

If the WUR was rebuilt recently, the control fuel pressure should be closed to specification. The pressure numbers are out of spec. But your biggest problem is the residual pressure loss.

The second link you posted about hot start is more confusing to beginners like you because it added culprits for a non-running motor (defective fuel distributor). Your car is an SC and the WUR will not cause residual pressure loss. Why? Not everything you read in the Internet is TRUE.

Tony

[flyboy182]

Agreed! Searching for CIS truth is my mission...

I did one other thing since my last post...removed the FA. I disconnected the bottom hose first. LOTS (repeat LOTS) of fuel poured out of the bottom connection. I then removed the two top connections in order to remove it and there was still fuel that came out of the top (mostly from the outer opening not the centre one).

I read one of your earlier helpful posts for someone else and learned some fuel from the bottom is normal/OK. But as I said a lot poured out. Does this imply I have found a failed FA?

Re the WUR...yes rebuilt, but I don't know the origins of it or by whom, and clearly I am getting the wrong readings per my initial test and as per the photo you can it has been hammered at before. Tony can I open it and try to fix this one or just send this away as a core and hope for more success with another "rebuild"?

[boyt911sc]

Originally Posted by flyboy182

Agreed! Searching for CIS truth is my mission...

I did one other thing since my last post...removed the FA. I disconnected the bottom hose first. LOTS (repeat LOTS) of fuel poured out of the bottom connection. I then removed the two top connections in order to remove it and there was still fuel that came out of the top (mostly from the outer opening not the centre one).

I read one of your earlier helpful posts for someone else and learned some fuel from the bottom is normal/OK. But as

• Take a deep breath and blow air.

I said a lot poured out. Does this imply I have found a failed FA?

Re the WUR...yes rebuilt, but I don't know the origins of it or by whom, and clearly I am getting the wrong readings per my initial test and as per the photo you can it has been hammered at before. Tony can I open it and try to fix this one or just send this away as a core and hope for more success with another "rebuild"?

Now that you have the fuel accumulator removed from you car, test it! Do a pressure test using the top upper ports. I have posted in this forum a simple way to test the FA by placing it a glass of water and partially submerged the bottom. Use your thumb to cover one of the upper ports and blow air into the other top port. I use different methods successfully to test a ruptured FA diaphragm:

[boyt911sc]

Originally Posted by flyboy182

Agreed! Searching for CIS truth is my mission...

I did one other thing since my last post...removed the FA. I disconnected the bottom hose first. LOTS (repeat LOTS) of fuel poured out of the bottom connection. I then removed the two top connections in order to remove it and there was still fuel that came out of the top (mostly from the outer opening not the centre one).

I read one of your earlier helpful posts for someone else and learned some fuel from the bottom is normal/OK. But as I said a lot poured out. Does this imply I have found a failed FA?

Re the WUR...yes rebuilt, but I don't know the origins of it or by whom, and clearly I am getting the wrong readings per my initial test and as per the photo you can it has been hammered at before. Tony can I open it and try to fix this one or just send this away as a core and hope for more success with another "rebuild"?

Flyboy,

This a good time to start learning to troubleshoot your CIS. Now that you have removed the FA from the car, test it. There are several ways to do it. One of my favorite procedure is to partially submerge the FA in a glass of water and blow air into one of the upper ports and plugging the other upper port using my thumb. Take a deep breath and blow air into the port.

Other procedures:
1). Use a bicycle foot pump.
2). Use a battery operated tire pump.
3). Use air compressor.
4). If you know how to test run your FP, install the FA and connect the 2 upper ports. Leave the bottom port detach to observe the fuel flow (if any). Place disconnected return line from the bottom port in a collection vessel. Test run the FP no longer than 2 sec. If the FA is good, there will be no fuel flow at the bottom port. If it is bad (ruptured diaphragm) fuel would be dripping out.

Do not do test #4 if you feel uncomfortable. That’s OK.

You need a CIS pressure tester kit if you like to investigate your WUR and the skill to manually operate your FP. If you are NOT ready, that’s OK and we will walk you step by step to get to the next level.

Tony

[flyboy182]

Yes I have the CIS test kit that is what allowed me to get my initial readings to indicate trouble with my WUR. I will try the water test approach. Top ports full of water and then pressure up one and thumb on the other. I will give it a go...

Thanks
Bill

[boyt911sc]

Originally Posted by flyboy182

Yes I have the CIS test kit that is what allowed me to get my initial readings to indicate trouble with my WUR. I will try the water test approach. Top ports full of water and then pressure up one and thumb on the other. I will give it a go...

Thanks
Bill

Bill,

You misunderstood the test procedure for the fuel accumulator test. Get a glass of water and partially submerge the FA. You need half of the FA in water and upper half out of the water. Then blow air to one of the upper port and at the same time plug the outer upper port.

If the FA is good and you had blown enough air, there will be no air bubbles in the glass of water. If you see air bubbles, throw away the fuel accumulator. Repeat the test to confirm your test results.

Tony

[flyboy182]

OK I tested the FA per your suggestion with a glass of water. Bubbles for sure coming out the submerged lower port. So success! Well if success is defined as one part to purchase and replace...

[flyboy182]

Update: I adjusted the WUR using the "pound the pin" method...first pounding the pin back out as my cold pressure was way low. First attempt it was then too high so pounded the pin back in a bit and now I have CCP around 2.1bar...right at spec.

However my Warm CP is not rising high enough when I plug in the WUR and let me warm up. It stabilizes after about 4 minutes but gets only to about 2.7bar. Spec calls for 3.0 to 3.4...so somewhat low.

What does this suggest as a next step...get my CCP up a bit more to the high side of the cold range and maybe the WCP comes up enough into range?

Any thoughts here would be most appreciated. Thanks. Bill

[kepa75]

Hello Bill,

To get your warm control pressure up, you need to push the complete valve body in, but be careful, a small movement changes imidiately the pressure.
But before doing something, I would also check if your vaccum is correct on the WUR, as I have not read about it.

Last but not least: which screws on the airbox were thightened ? The screws that hold the airmeter to the box are on springs and are supposed to be not completely thightened.

Ciao,

Peter

[flyboy182]

Hi Peter;
Thanks for the response. My WUR ending in -090 has no vacuum, just a vent. The screws that were popped up were 4 on the outside left side of the airbox looking at the engine and all of the screws inside the airbox under the air filter. It seems the car had a "pop" and with no "pop off" valve it didn't completely destroy the airbox just stripped the screws out from the plastic.

I played with the WUR some more pounding the pin in and out and testing. I must have removed and re-installed it 15 times...

I now have it I think within or close to spec. 3.2 Bar warm and after putting it in the freezer for a while (guessing it was about 15C when I took it out) I had about 2.3 Bar. Slightly off on the cold side but it was crazy sensitive and I was running out of patience...

Bill

[flyboy182]

Hello all;
Sorry to keep re-posting but I also think closure is important on these forums. Happy to report I think I have fixed the major issues with the CIS. Hot starts now fine after changing the FA with new. Hunting and surging gone now that CCP and WCP are closer to spec. I think the car is still running rich, but I don't have the tools to properly set that so I am going to take to a local shop in a week or two see about checking all settings and possibly changing the decel valve that is still dis-connected and when re-connected causes hung idle.

Many thanks for the replies and assistance.