Porsche_Monkey and Sal,

I checked it before I had it rebuilt and it was OK. I could also feel it heat up. I think I may be able to check it via the connector on top of the WUR. If I can't get the CPs to change after I try some more plug raising and lowering, I'll definitely check it once I open up the unit and check the bend. I'll see if I can observe the amount of heat related bending, but it may be too little to notice.

BTW P_M,

I found your post back on 1 Jun 04 re setting WURs very helpful.

Ahh yes. The CIS days. Can't say I miss them. :)

I am behind and just found your thread. One thing from your original post has been bothering me.

Turning the idle screw doesn't change the idle speed.

To me, this is a major issue that points to a major vac leak. I can't believe good mechanics haven't noticed this clue. From my experience, this needs to be fixed first.

My opinion? Milt nailed it in the first page. Blown air box (or other major leak).

Best of luck.

paul, i have figured it out, you are trying to get a post longer than your last one.
this will help.

did you ever get hold of an LM?

Ty,

You're right! I'm going for a Pulitzer. Part of the problem is I haven't been able to actually spend much time on the car. I'm actually spending more time responding to posts. :D Not complaining. I'll get back on it tomorrow. LM coming soon.

Dave,

A vac leak has never actually been ruled out by me. Once I get the WUR working and can drive this thing, I'll have it checked out.

And I should clarify. The idle screw has been doing its job throughout most of this ordeal. It's just recently w/ my apparently messed up sensor plate/cp/ mix condition that it's not doing its thing past a certain point.

The "Saga" continues.

Since I hadn't yet come up w/ a known good WUR I decided to do some investigating. In previous recent tests, I was able to easily start the engine, but the CPs remained low despite current, engine heat and time, and the engine ran w/ too rich symptoms.

So I disassembled all 4 of my WURs and checked out the bimetal arms. All had resistance near the spec stamped on the heater element, and all heated up to the point of being too hot to handle. Only one of the arms, however, actually bent while being heated. Even the arm of the recently rebuilt WUR failed to bend.

So I decided to make up a good WUR using the one bendable arm and the bottom, vacuum controlled portion of the rebuild. I felt somewhat confident that a bendable arm, coupled with what seemed to be a good base, would get me going. Ambient temp was 10C, which seemed perfect for CIS troubleshooting.

THEN THE "FATAL" ERROR.

Following the advice of others I raised the cold cp plug to where I felt it would be freefloating. This way I could observe and set the WCP to spec, and then knock the cold plug down to the cold starting spec, and enjoy "happy motoring" once again.

After hooking up the WUR and priming the system I was ready to go. A couple of spins of the starter, a ridiculously loud BANG and all was quiet.

I think I blew the airbox.

I think I should have first knocked the plug down to a cold CP level, as I had always done, started the engine (even if too rich) and got it warmed up at least a little before trying this. Right now it seems that the "freefloating" cp was just too high for a cold start, even @ 10C. The engine will not start now, no matter what cp is used.

I'm not trying to point fingers here. I think the procedure that was suggested is the right one. I should have been more careful in making sure the engine temps first matched up w/ the CPs. I just want to get this in the database as part of the procedure.

So now it's off to have the airbox checked out. I think it's also time now to do some further investigating, perhaps into the world of PMOs or t-bitz.

In talking w/ my local supplier, he said that new WURs were NLA, and that the arm was the part that usually fails in the oldies. No surprise there. He is trying to source out a way to repair the arms. I noticed on mine that the bottom side, which appears to be a very thin bronze like material, seems quite tarnished. Not knowing anything about metallurgy I'm wondering if these things just fail over time because that material somehow disintegrates, vaporizes, fatigues, or whatever. It seems that maybe if a new coating could be applied, plated on, or bonded to it, these things could be made to work again.

So Happy Easter/Passover/just plain weekend to everyone. As always, I'll continue to update as things develop. Thanks for listening.

CIS troubleshooting..........
 

Paul,

Sorry to hear that you are still looking for the source of your problem/s. It has been mentioned, suggested, recommended by others that two things that may cause this problem are vacuum leak and fuel pressures. These are two different and separate aspects of CIS troubleshooting. Unless you can determine the status of your vacuum system and fuel pressures, your problem will be very difficult or impossible to correct.

You don't need to run the motor to determine your vacuum and fuel pressures. Ricks911S has recently attached some demo movies for his troubleshooting. His WUR's pressure vs. time profile is what you need to get for your car to run provided you get rid of that nagging vacuum leak.

Since you insist in using your WUR's (hybrids), test them before running the car (follow Ricks911S procedure). Concentrate in making it run first and idle consistently. The warm condition parameters will follow next. Please avoid messing the air mixture screw. You had tinkered this screw so many times without any good results. Have the exhaust analyzed using the correct instrument (gas analyzer from proffesional shop) and once set, leave it alone.

CIS troubleshooting is not difficult!!!! Send your motor to me and I make it run. This is how I feel about your problem. Have an open mind and listen to the suggestions given to you by others. CIS is all about vacuum and fuel pressures. So concentrate on these two things. Wish you luck.

Tony

Thanks, Tony. The "Quote" feature isn't working for me right now so here goes:

I'm trying to do what you say in 1st para: 1. determine pressures 2. find and fit a good WUR 3. drive car to a shop to do a smoke or pressure vac test.

Para 2: The fuel pressure was and is 4.85 bar/70psi. I'm trying to get that profile. The ones I have been getting have all been bad. They've all been posted.

Para 3: Since my one "known good" WUR crapped out after only 1 test, and I couldn't get another for a while I decided to try something instead of just sitting and waiting around. After all, is it turned out that seemingly good parts from 2 sources turned into a good WUR, then I'm ahead financially, time wise, and the problem is solved. Remember, it's not necessarilly so that all the components in a WUR will fail in order for it to not work correctly. The reason I've been doing the cp tests w/ the engine running is because that is the procedure as outlined by this BB, the Bentley and Souk. I've never seen cp tests done w/ the engine off. Why doesn't too much fuel get dumped into the engine, since the valve is open and the pump is running, but the engine is off?

I will try this now. The WUR I was using was a "hybrid" since it was the only one w/ a good bimetal arm. I already had determined that the ones w/ bad arms produced low cps that stayed that way.

I haven't messed w/ the mixture screw since last fall, and this was part of the procedure in trying to get what you describe as idling and running consistently. I had an A/F LM-1 on it last fall and it was set @ 13.1 @ idlew/ the WUR in use @ the time. When I put the new one on and retested this spring, I almost immediately put it back to approx where I have had it for 17 years!

I have been following suggestions provided by you, Porsche_Monkey, Souk, jonbot, Ty and stevemfr and others, all of which I appreciate.

The troubleshooting is not difficult,as you say, provided the WUR you are using as "known good" actually is!

BTW my airbox may be OK. I'll let you know.

I wish I could send you my engine. Instead, pleas send me a "known good" WUR.

Paul,

Hope your air box is o.k. as you suspect.

Fuel won't be dumped into the cylinders as long as the plate in the plenum is seated--that's what triggers the injectors, not the fuel pump. If all things are working properly, the pump will circulate pressurized fuel and you should be able to take pressure readings without the engine running.

Thanks, LJ. That's good to know. Wish I had known that about the CP test. Everything I had read said to have the engine running. If it turns out the box is blown, that could have been eliminated by doing the test that way. :(

Paul,

I think that you do in fact need the engine running if you are using a WUR that has the vacuum line. Or, you could use a vacuum tool to create the proper vacuum at the WUR.

I had this debate recently when someone insisted that my engine be running for the tests. I contacted Jim Williams and he said that then engine doesn't need to be running to test non-vac WURs.

This is exactly why I think there should be CIS forum. Each year of CIS seems to have little variables that can make a BIG difference when troubleshooting. Everything from the 02 sensor, to the frequency valve, to the FP, to the FD, etc. It gets pretty hairy across all of the years.

So, do you not have a pop off installed? Just curious.

Craig

I am not an expert but have discovered a lot.


Maybe my layperson explanation will be of help.

System pressure feeds the injectors ..

The WUR ...Bleeds off pressure that controls the mixture metering piston.
The pressure does not go back to the injectors ...

When cold pressure is low (lets say 1.5 bar) the piston is able to move more freely ...allowing more fuel to enter the system to the injectors.

When warm the pressure is higher (lets say 3 bar) the air passing by the air plate ... moving the mixture piston up ... now meets more resistance so the mixture is leaner.

If your warm pressure is to low ... you will be too rich
if to high you will be to lean.

So before you can set idle (actually a lean bypass in the TB) or the actual mixture your pressures have to be set.

I was looking for a "flowchart" for trouble shooting.

Found a symptom chart ...

But my tests will always start with:
#1 fuel flow and pressure from the pump
#2 system pressure
#3 Warm pressure
#4 Cold pressure

also remember that pops and backfires can be caused by LEAN system not always rich as one may think.

i hpoe the air box is not blown! was it so bad the popoff valve did not make a diff? i have a spare air box, but it is from an 80, i know the runners a different so i assume the airboxes are too.
the heated spring is what goes bad, my bad WUR gets hot but no bend. that is why i usually just tell people to get a new WUR when they have to start changing CP's.
i know this is too late, but you should have pushed the air plate up for extra fuel to compensate for the lean cold start. while holding the air plate up, adjust the mixture for a rough setting that the car will idle with out holding the plate.

if you have a popoff valve, make sure it is seated, it make be off it seat.

Geez, this thread is going to have to be re-named 'Bad to Worse'. Stick with it Paul, in the end it will be a victory to savour. Even if the driving season is over when it happens. ;)

And what MCA says makes perfect sense. Vacuum WUR needs a running car.

Thanks again everyone.

I have a popoff valve. It does pop correctly and does not seem to have jumped out of the box or loosened up in any way. The screws inside the box are nice and tight so I may be OK. I can't see any cracks around the exterior, but obviously that's limited as the box is on the engine in the car. All my testing has run the battery down somewhat so I'm currently recharging. I'm hoping this is the reason for the no-start. This battery is old so I may in fact need a new one.

Does anyone know another way to check for airbox leaks w/o removing the box? I know--smoke or pressure test. LOL! I'll get one. I just want to get the car running first.

Right now I'm trying to soure a new WUR from Bosch/Bosch distributors. I'm thinking this way I'll know it is guaranteed good.

In the meantime I'm trying to find out if the bimetal arms can be relaminated to get the bending action back. All my arms heat up and have the correct resistance. 3 of them just aren't bending.

Wyvern,

Fuel pressures, flow and pattern are all good. I just need a working WUR!

Tony,

Thanks again for more tips. I was holding up the sensor plate for most of the starts, but I can't say for sure about that one. You're right about the runners. I'll have to see which airbox I have. I think it is for the small runners of the '80, but I could be wrong. I've noticed some Pelicans have repaired theirs using a particular 3M marine silicone.

Craig,

A CIS forum sounds like a great idea!

You know, the manuals have a chart for vac WUR values w/ the vac line removed. Maybe the thing can be tested w/ the engine off as long as the line is disconnected.? I'll try Jim Williams.

Do the WUR manuals say to disconnect the vaccum? If so, then plug the vacuum hose and set the pressure with the engine off. In hindsight (my area of expertise) get the WUR pressure close with the engine off and then tweak it with the engine running.

Kudo's to your good attitude. Not sure I'd be that pleasant in your shoes.

he can set the CP with it off, let the WUR heat up for a few minutes. but mixture will be so far off from running with low CP's it will still backfire if you are not carefull. raise the plate by hand and richen the mixture once it is running. make sure the CCP pin has no effect while setting WCP.

[QUOTE=Porsche_monkey;4603433]

hindsight (my area of expertise)



LOL!

I have an email in to Jim Williams about vac WUR testing w/ engine off.

Bentley's has 2 charts--1 for warm running w/ vac line attached; 1 for warm running w/ vac line removed. It doesn't say to plug. They are about .5 bar lower w/ line removed.

you do not need to plug if the engine is off.
but it is nice to have a hand vac pump ($40) so you can pull a vac to make sure you are getting a CP change. it is a very usefull tool to have anyway.
i verified CP when the WUR was cold and when it was hot, wiht the engine on and off, no difference when off. what i did was to verify the vac needed to make the max change in CP, then measured the vac from the motor to make sure it was enough to make the max change.
the chart you posted had CP for vac and without vac, i think it was 3.4 and 2.4??? or was it 2.8?

good to see you got the spring issue sorted, hopefully.

Thanks for testing that, Tony.

The chart in Bentley has a ccp @ 10C of about 1.6 to 2.1. Then it shows a figure of 3.2 to 3.6 warm and running w/ vac, and 2.7 to 3.1 w/ vac line removed. I'll try w/ the engine cold and not running , and the engine warm and not running (actually the WUR warm since the engine is off!) I'll see if I can pick up a vac pump locally and try to use it to approximate the engine vac.

What figs did you get for cold, and @ what temp? And for warm?

The rebuilders in CA are taking the WUR back and will rebuild it again for me. As I mentioned earlier, the cp varied by only 1 bar when first tested, and then failed to raise @ all thereafter. I'll have them set it to the factory spec.

If I get a hand vac pump is there some way I can use it to check for vac leaks?

Don't think so. But if you search online you will find a way to do it with low pressure compressed air and soapy water...

This may be heresy, but have you considered the UTCIS (digital WUR) from Unwired Tools? Pelican sells them. At least on paper it looks like a good alternative to having the mechanical WUR rebuilt over and over. The UTCIS-V does closed-loop monitoring of the control pressure and supports programmable warm-up cycle and adjustment based on engine vaccum. No fooling around w/ screw adjustments, just program once and go.

Luckily my CIS is behaving but if I ever have to deal with the WUR, I'm probably going to the UTCIS or something similiar. Last I read the were working on making the naturally-aspirated version multi-variable (i.e. Exhaust O2 sensor). I have a '79 and would love to add programmable close-loop O2 monitoring without having to do a full EFI conversion or salvaging a "newer" CIS system.

Pretty sure he considered it last time....but I agree he should maybe go that route.

Air leak detection.........
 

Paul,

All you need is pressurized your system like testing a radiator. Plug all known open orifices and inject air. You could use an air compressor or a bicycle air pump or a brake power bleeder to inject pressurized air. An air pressure between 10 and 15 psi is sufficient for the test to form bubbles with soapy liquid.

As soon as I finished my engine rebuild (not a Porsche but a 4Runner) this week, I'll set-up a pressure test show and tell for you guys. Old and antiquated procedure but very effective in locating air leaks. HTH.

Tony

Hey Paul,
I feel really bad for you - and I don't know if I am not at least partially to blame. I should have spelled out in detail that setting the CP's (both cold and warm) is done by jumping the fuel pump relay with the motor off. I think when I outlined the procedure in the thread last year, everyone had been chattering back and forth so much about setting the pressures, modifying WUR's, etc. that I just assumed that everyone was up to speed on this point - and I never checked again. The CP's are the very basic set-up parameters for your mixture, and these need to be set before starting the motor. Only the fine adjustment of the mixture is done with the motor running.

It does sound like you found the problem with the non-bending bi-metals. I wouldn't necessarily spend a great amount on a new regulator at this point in your shoes.

Try the following for a possible quick-fix. Set the CP's w/o the motor running:
- Disassemble the WUR, knock the diaphragm disc and the cold pressure plug upwards in the WUR housing, reassemble and connect the fuel fittings to the WUR with the pressure gauge in place. Important: leave the electrical connector for the bi-metal heater disconnected.
- Jump the fuel pump relay (fuse box - trunk) by making a short jumper wire with 2 male bullet connectors and bridging terminals 30 and 87a in the relay connector. With the fuel pump running, knock the diaphragm disc down until the warm pressure is to spec. Then knock the cold pressure plug down until the cold pressure is to spec. Apply 12v to the heater connector on the WUR - the cold pressure should climb back to warm pressure spec. Your CP's are now set.
- Wait for several hours for the WUR to cool down to cold spec Your car should now start and run quite well. You'll now need to set the mixture with a CO meter.

Sorry once again for not spelling out that the motor should not be running to make these adjustments. Hope the airbox is OK and this helps!

Steve

mine only changed by 1 bar from cold to warm.

Thanks, Steve.

I'll be checking again soon once the battery is charged up or replaced. I wish I had known about the "engine off " procedure, but virtually everyone, not just you, always talks about the CP test w/ the engine running. In the meantime I have my rebuild going back to be checked. FWIW I can try your procedure w/ another one I have just to see if the engine starts.

BTW the jumper wire should be between 30 and 87a, not 87. Again, this is what is always quoted.

Tony,

Your ccp to wcp probably only neede to go up 1 bar. What's your ambient temp in SC now? 20C? It was 10 here when I did my last test and I needed to jump about 2 bar.

Typo clerical error.......
 

Steve,

Your advise to Paul is what I really wanted to hear. In my earlier post, I mentioned that he does not need to run the motor to check his CCP, but others have offered different opinions. BTW, I think you meant 30 & 87a instead of 30 & 87. Thanks.

Tony

longhornchris and Porsche_Monkey,

I have considered the unwired tools model. If these bimetal arms and their heating elements start going and can't be fixed, it someday may be our only option.

Tony,

I can use my tire compressor to get air into the vacuum line, and then see if I get any soap bubbles forming around hoses, components and connections. Is that right?

What about the airbox?

BTW my WUR is on its way back to be rebuilt, recalibrated to '79 specs and tested. I probably won't have it back for about 2 weeks, though:(

Sealing air-box..........
 

Paul,

There are different ways to seal the airbox for this kind of test and you could do your own version. Here's what I did:
1). Put a nice sheet of saran wrap or plastic film on the inner side of the air filter and stick back the air filter. Just be aware that the perimeter of the air filter is another possible source for potential air leak.
2). Or a 7.5" X 16.5" plexiglas sheet with rubber gasket to replace the air filter.

For air injection inlet, the're several points where you could use. Namely, oil filler tube, vacuum supply for the brake booster, the nipple by the side of the air box, vac line to WUR, distributor, TV, or at the muffler (I don't recommend), etc.

The key to this test is to maintain a steady low pressure inside the system. A 10 psi air pressure is sufficient to do the trick. Or at most 15 psi. So you need a pressure gauge hook up and it will tell you if you have sufficient pressure for the test.

Additional tips:
a). Place a vinyl or latex glove over the the oil cap tube (cap in place) and secure with rubber bands.
b). Removing the muffler will reduce the area where air leak may occur, but if you decide not remove it thats fine. Cap and seal . Place glove and secure.
c). A small jar of high temp. vacuum gease will come handy.
d). Masking tape or duct tape, large dia. rubber stoppers maybe needed.

Anyone who has any suggestion or comment to this antiquated procedure please chime in. Take a look and see if you have something to contribute or share. HTH.

Tony

PS: Paul, we are on the 6th page already!!!

And he hasn't even fixed anything yet. ;)

(Good natured) LOL.

Paul is the sacrificial lamb for all us CIS owners who have been, or will be, in the same situation.

Paul, we're all pulling for you, even though the thread is becoming a tapestry.SmileWavy

I resisted the urge to say 'So far he only blown schit up'. :)

You need patience, money, and a sense of humour if you own an old Porsche.

Yes it should - don't know what happened to my 'a'. I edited my post for future reference.

Paul, I do hope it works for you. If I were closer, I'd shoot over and give you a hand. It is not difficult - please continue.

I really didn't realize that there were such misconceptions about setting the CP's. Setting the pressures with a running engine to me is like building a plane and adjusting the control surfaces during the maiden flight....

You guys are CRUEL.;)

I'm busy w/ work demands right now, so you may not hear from me for a couple of days. I plan next to see if I can at least get the car started to determine if the airbox is indeed cracked. I may also need a new battery. If the box is cracked, obviously I'll have to fix or replace it. I'll have to give Tony's test a try too. Then, when the newly refurbed WUR is back here I'll give it a go.

If you need a hand PM me. I'm cruel but willing to help. And not working right now..

P_M,

Thanks a lot. I'll PM (P_M?) you.

Yes, PM me, maybe Mark930 will also help.

Well, the newly recalibrated WUR, set to factory '79 specs is here. My parts should be here tomorrow. And once I get my pesky client work out of the way, I'll start cleaning the airbox to check for leaks, and repair the hole I found in the AAR/AAV line. Thenit's everything back on the engine c/w some new seals, gaskets and hoses.

If all goes well, it'll be just a few days.

longhornchris04,

If I can't get my WUR working, the UTCIS is definitely an option.

Paul,

I hope that the small hole in the Alu-pipe caused your problem but somehow I don't think so.

It's been a long LONG story going on and on with various threads about your CIS without any end in sight.
At this rate, we'll go into 2010 page after page. :rolleyes:

When a thread gets that long and complicated, after page 5 one loses sight of what is being attempted or what method is used to find the problem.
There are way too many theoretical questions and suppositions on these threads.

Several months ago, I asked about details for your engine like size and type of P/C's, CR, crank, CIS, FD, distributor etc.
You weren't sure then, indicated you'd find out, but we still don't know what you have.
The bottom is a 3.0? Or 3.2? But the distributor has points?
Has the worm gear to drive the distributor been changed on the crank??
What is the rotation of the distributor?
CDI is a Bosch 3-pin module? Or?

It would definitally help you and others if you could post correct details about your set-up.
The engine case has a type number.
What is it??
The Bosch numbers on the components tell the story.
What is the Bosch number on the FD ??
Distributor Bosch number??

As a ME, I am used to a methodical trouble-shooting procedure knowing first the details and characteristics of the components and the system being worked on to prevent endless guessing.
How about posting some relevant details of your engine?
If it's a mix-and-match, one needs to know what is stock and what was changed and why?

Not being negative, just realistic. SmileWavy