Need More CIS Help, Please

[Paulporsche]

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.

[Porsche_monkey]

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

[dlagerstrom]

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.

[T77911S]

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?

[Paulporsche]

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. 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.

[Paulporsche]

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.

[boyt911sc]

Originally Posted by dlagerstrom

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,

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

[Paulporsche]

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.

[ossiblue]

Originally Posted by Paulporsche

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

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.

[Paulporsche]

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.

[mca]

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

[Wyvern]

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.

[T77911S]

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.

[Porsche_monkey]

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.

[Paulporsche]

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.

[Porsche_monkey]

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.

[T77911S]

Originally Posted by Porsche_monkey

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.

[Paulporsche]

[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.

[T77911S]

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.

[Paulporsche]

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?