Where Does This Vacuum Line Go?
 

While trying to solve a start and run problem w/ my car I've switched to an alternate WUR. It's the one shown w/ no vac lin attached to the lower chamber. The exploded view shows a top port (see connector no 15) but does not show a line attached. Is this an atmosphere line, in which case it can either be left open or ultimately attached to the top port of the throttle, or is it a vac line and need to be ultimately attached to the lower throttle port? I currently have it attached to the top port of the TB, thinking it is an atmo line.http://forums.pelicanparts.com/uploa...1218912063.jpg

Paul,

Jim Williams Porsche Page has some great references:

http://members.rennlist.com/jimwms/CIS/CIShome.html

On the earlier 78 and 79 that vacuum led to the throttle body.

http://forums.pelicanparts.com/uploa...1218926694.jpg

Also the vacuum connections for the '80 - '83 CIS deceleration valve (13) has changed, and the frequency valve (8) has been added, which is controlled by the Lambda sensor electronics box.



http://forums.pelicanparts.com/uploa...1218927008.jpg



Hope some of this helps,

Shane

Shane,

Thanks. I've seen those. The first illustration is what I had and described. The top is atmo, & bottom vac.

I think the fact that there is an open port shown in the illus I posted, and no vac line in the one you did (from Jim W) then that confirms that the top port is atmo only.

It is atmo, if you look at the WUR's listed on Jim Williams pages he has four models listed side by side it shows no atmo for the 80 Wur just a hole, so you must have a 81-83 WUR.

Thanks again. At least I know I have it connected correctly. Now I can move on to injector testing.

I have one for '80. It ends w/ 072. Apparently Bosch actually had 2 versions of this number; one w/ & one w/o the top nipple.

paul, i dont think that WUR will work. the vacuum port acts like an accelerator pump on a carb. it enrichens the mixture when you put your foot into it.
my brother owned my car before me, he had some "issues" with the WUR, he tried adjusting it and so forth. finally he just bought a new one, it fixed his hard starting and it runs a LOT smotther now. hint hint:D

T77911S,

The WOT enrichment vac port for an '80 is deleted since enrichment is handled via the Lambda control system. On a '79 this is the lower line, not the upper.

As you know from my other thread I have tried 4 WURs. 3 were old pre lambda types. The one currently in the car is for an '80, which is what my engine was originally, although since modded, incl removing O2 sensor and system. This WUR was purchased new.

I recently took 2 WURs apart. They looked brand new. I have also made them adjustable.

The current one in the car is in spec, but, as you have alluded, I still have a problem. However I have the symptoms @ idle. The engine smooths out @ higher revs. I'm going for a test drive today and will report.

However, you may prove correct in the end and I'll need to replace it. Maybe one of the new high tech, programmable ones...

year is the rest of the cis?

I think it is from an 80, although the WUR was a 045, which is for a 79, which I think was used since there is no O2 system to otherwise provide WOT enrichment. This engine and peripherals were installed in my car about 17 or 18 years ago.

i think i would got with the WUR for the 78-79. i am curious as to what the pressure change is between the 77 and the 78-79 with and without vacuum. mine is 1 bar, if the 78-79 is different i would use the one that has a higher pressure difference. that would give you more fuel when you put your foot into it.

I agree. I originally had the 79 on the car. When it failed, after about 14 years, I switched to the Audi 5000 one, which lasted about another 4. It's only because those 2 didn't seem to advance beyond the CCP figure that I tried the new 80 one. That one at least matches figures for an 80 engine. Now that I've cleaned etc the other 2 I'm going to try them and see if we can get this thing to work.

I don't have a 77 one anymore. It went along w/ my old engine.

I've been unable to get a graph for the Audi one.