CIS - WUR pin knocked in too far

[Sean Hamilton]

I've been having rough idle at start up when cold. Goes like a scolded dingo when it's hot.

As an aside - I've also had a gut-full of the cold start CIS surging and dealt with that by plugging the AAV - what a mongrel job that is, to get to it!! Took two hours and all the skin off my knuckles "feeling" for the concealed nuts and hose clamps. Anyway the surge has gone so that's that done with!

But in an attempt to deal with the rough cold start idle, I had a go at tapping that pin in on top of the WUR thinking this'd richen it up a bit more when cold. I reckon the WUR is an original 23 years old so it's probably half knackered by now anyway. What have I got to loose? PLENTY - Porsche turned to into a pig! I attempted to start the car and it blew black smoke, ran like an old chaff cutter and would immediately die if I took my foot off the accelerator.

Seems I tapped the pin in a wee bit too far. So I was left with no alternative but to remove and dismantle the WUR and knock the pin back to where it was ...... sort of? Gees, these WUR's are sensitive little buggers. I only knocked it in maybe 1mm and it was enough to paint my garage ceiling with black soot! (I can still hear the dog out back snorting and grinding her nose into the gravel trying to get the poison out of her nostrils!)

The car is now back to where I started - nowhere! At least it's running, but horrible when cold and terrific when hot. OPC says replace the WUR. Haynes manual says no, replace the AAR. I'm at a loss. Maybe I should replace both but at $450 AUD a pop it'll be expensive.

BTW, OPC says I'm not doing any favours by driving the car each day for only the 10 minute run to work . It never reaches proper operating temp. It's true in that when I take it on a longer run (more than 20 minutes) it's a different car to drive - wonderful. But less than that? it's ..... okay.

[Jbabic]

Make it adjustable....plenty of pics on the BB to show how.

[Sean Hamilton]

Originally posted by Jbabic
Make it adjustable....plenty of pics on the BB to show how.

Wow, I didn't know that this was possible.
Thanks - can you point me in the right direction for the pic's?

[edit] GOT IT! - WUR modification (Make it adjustable) scetch?
Now that's clever!

[tsuter]

I have banged em in and banged em out many times. I doubt they can really be pulled back up by the little screw trick as proposed though it is theoretically interesting. In any case too much bangin will crack the ceramic on the bimetalic strip and then you won't get good heat transfer so you get to buy a new one anyway.

[Bill Verburg]

The adjustable mod is nice but w/ a little practice one can become quite good at r & r-ing(and pulling the pin back out) the wur. I used to be able to do it in just a few minutes.

[1980SC]

The screw modification does indeed work very well. I've used it to raise and lower the pin on my WUR many, many times.

Rob
1980SC

[Gunter]

Unfortunately the Pelican article shows no picture. There are different types of WUR's, so, do a search. I, and other non-doctor, Phds. posted some schematics. Did you just knock the plug or did you also dismantle and clean everything? Does yours have the lower vacuum chamber? Is yours ROW? Is Australia considered Rest of World and how do you feel about that?

[Sean Hamilton]

Originally posted by Gunter
Did you just knock the plug or did you also dismantle and clean everything?

Yes, and in that order.

Does yours have the lower vacuum chamber?

Yes.

Is yours ROW? Is Australia considered Rest of World and how do you feel about that?

Cheeky bugger, yeah........ we're the "better half"!!

When the pin tapped in, does this alter the mixture for all operating temp's?
i.e. Will it be richer all the time and not just at cold for the warm up period?

[Kemo]

Sean,

I was under the impression that the WUR is also the fuel pressure regulator for the entire system. I'm definitely not a pro, but thats what Ive gotten from alot of reading trying to understand the whole CIS thing.
BTW, where is the Auxillary Air Valve on your SC. Mine is a 78', so they should be very similar.

[Gunter]

I have 2 operational WURs for my '80 SC US. That year stands alone for a WUR. (No lower vacuum chamber) I was so alarmed by the cost of a WUR that I advertised on the 'Parts for Sale' pelican site and found a used one (Thanks Robert) I also take along a spare BOSCH CDI module (which is about US$1400.00!!!) and a pump among other things. Just trying to have these items in case I get stuck in the middle of nowhere. At the time of my WUR-postings, there were some good replies from someone on WUR's with vacuum chamber on this board. If you don't have a Bentley SC manual, get one, it's the way to go even if you have to read it upside down where you are.

[tsuter]

The WUR also called the Control Pressure Regulator by some alters the mixture for all operating temps if you bang it in so far that the bimetal strip never lifts off the valve spring when the engine comes to operating temp. Easy to do. Hard to compensate with the overall idle mixture control.

[Sean Hamilton]

Something has definitely run amuck with my CIS.
Today was a hot day (a stinker!) so decided to go for a spin. Still splutters and stumbles when cold starting. 20 minutes later - Engine nice and warm, at the first stop the idle hung at 2700 rpm !! WTF ? Only way to bring it down was to flick the A/C on. Maybe I've set the idle speed too high in an attempt to compensate for the poor starting issue? I'm chasing my tail.

tsuter - Thanks, I suspected as much and now I have no way of adjusting the mix without the proper tool and oxygen sniffer. Anyway, I've had a gut-full of it now. I'll send it back to my OPC and they can deal with it $$$$. Strange how this has only occurred since the last major service.

Kemo - The AAV on mine is tucked away almost out of sight between the fuel distributor and the fire wall, right of centre of the engine bay. As I said - not a happy experience and a mongrel to get to.

Gunter - Yeah, the Haynes manual wasn't much chop, even when I read it back to front it didn't improve.
Next time you're Down Under, come and shout us all a round at the pub - we can teach you to read what's for dinner on the menu - upside down and legless on the pub floor.

[Gunter]

Shawn: Have you tried to check for vacuum leaks? It sounds like a mixture problem which could be WUR, AAV, AAR, Throttle switch, Leaks?Consider getting a fuel pressure gauge. That way you'll take the guess work out by following the steps in the Bentley. Rather than trying to replace parts, the cost of a FPgauge will be recovered by the savings of time and energy. Adjusting mixture when all other things are o.k. is no big deal. No special tool, just a long handle 3mm Allen wrench will do it. Very small fractions of a turn will get results and you have to remove the wrench before you rev up. You can do it by ear and be very close. A lot of people go with 3.5% which is higher than what the manuals say.
The pub thing sounds good, but, how did you ever end up driving on the wrong side of the road Down Under?

[Sean Hamilton]

WUR:
........ with a happy ending .........
The problem was a knackered WUR.
OPC replaced it with a new WUR and so far - so good.

IDLE SPEED:
Still cant get used to how twitchy the idle speed setting on these CIS systems are.
Just a hair too fast at warm idle and it'll hover way too high at HOT idle.
Still had to tweak it down a bit after getting it back from the OPC.

AAV:
An update on the plugged AAV - FANBLOODYTASTIC !
What a useless appendage THAT is!?!
No cold start idle surging any more - turn the key and GO! (Thanks to "Hladun1")
Edit: Summer here, so winter may tell a different storey? Keep you posted.

Gunter:
If you're ever in Melbourne, we'll introduce you to how we make a Right Hand Turn here (equivalent to your left turn into on-coming traffic) from the extreme Left lane, riding the clutch waiting for the 2 second delay between the lights changing from Go to Stop and then flooring it in the face of on-coming traffic from every direction. Tourists stand at the intersections marvelling at the spectacle!
Out-of-towners avoid driving into the city for fear of making these turns but when you've plucked up the courage and get used to it, the system works quite well.

Thanks all.