1981 SC CIS - low idle - wrong WUR?

[wreckah]

on a side note: i think the car feels a bit less smooth with the O2 sensor connected, especially driving steadily. Not a big issue, because i'm used to a very nervous KTM motorcycle, but just noticing it.
If i had a working km-o-meter i might discover some changes in mpg, but for now it's gonna be guesswork.

[boyt911sc]

Originally Posted by wreckah

hi groovy, yeps, 20 seconds of spluttering is not that hard to live with, especially since i need like a minute to get out of my garage, open the gate, close the gate, hug the dog, etc so by the time i'm out in the street the car runs great...

i'll try your throttle tap to see if it catches more quickly. We're still having very cold nights here (almost 0°C) and morning starts mean 5 seconds cranking before she catches.

Wreckah,

Your WUR is still suspect to me. What is the WUR's heater resistance (Ohms) when engine is cold? Have you checked and tested the spray patterns of the CSV injector and the six (6) fuel injectors? I have successfully started engines and cars well below freezing point temperature many times as tests. Keep us posted. Thanks.

Tony

[wreckah]

Hi Tony,

i'm aware that the WUR is still a very possible culprit...but where can you find a new one? i've been looking around for a while...nothing yet. And i don't feel like sending it off for a rebuild, that would mean a couple of weeks off the road...maybe next winter...
Will check the injectors when i feel like another testing session, but for now, i'm focused on driving the car for a little while, just enjoying it

cheers, Jan

[wreckah]

fuel distributor test OK, next up is injector test

distributor test =
- injectors taken off
- fuel lines in bottles
- bridge FP relay
- ignition on
- no leaks when airmeter is not touched, not a drop
- push the airmeter up, fuel starts coming, this is after about 30 seconds i would say
- all bottles are as good as identical

[wreckah]

injector test: full open, big spray



injector test: small spray, barely open, they all seem to open at the same time and spray very similar


i have a non-starter now, it's the green cable that is now brown and finally has given up after trying to wiggle it into a bend that works...new cable on order.

[xghyi]

Same color as my '79 Targa! I had a lot of CIS adventures this past summer. My car also has the "wrong" WUR, a Euro on a California car, but with proper setup it works fine.

[wreckah]

hi guys, i'm trying to get my head around the vacuum cleaner leak test.

i've attached the blower hose to the exhaust pipe, and can't find any leaks around the injectors or airbox, but one thing is confusing me very much:

when i turn the engine by hand, all of a sudden i have a huge airleak coming from the valve cover seal at cyl. nr 1. It happens of course when one of the valves from cyl 1 opens, but surely the valve seals should stop air getting past, no? Brand new revised engine by the way (12K € revision) , fully revised heads, valves, seals, chains, etc...etc...basically everything is brand new in there. No smoke, no oil comsumption, 5000kms since the revision. Any ideas?

cheers, Jan

[Vereeken]

Where do you live.?

It is very hard to get good cold start if you have a mix and match of components.

I know how to find good used WURS ...

The WUR are interchangeable but they also work together with the FD and many FDs exist.

I think Tony (Boytsc keeps a list of FD/WUR relationship.)

Also some of the references out there are not accuarte for EURO SC's (if yours is a EUro).

What is your CO setting when fully warm?

[wreckah]

Hi, i live in Dikkelvenne, near Ghent, Flanders,

these are my components:
WUR 0438140072
FD 0438100077
1981 USA SC

cold start issue is 99% WUR related, so if you could get a good one, that'd be great. After 1 or 2 minutes, the car runs and drives fantastic. Never checked CO.
This vacuum test was to make sure all lines etc...are good before i change parts. The air leak from the valve cover seems very strange.

[boyt911sc]

Jan,

It has been a year since you started this thread. What you have not shared with us is the heater resistance (Ohms) value. Or I have missed it. When the engine is cold, measure the resistance and post the reading. Thanks.

Tony

[wreckah]

Hi Tony, it was 11 ohms, i posted this some time ago. Should be higher, so it's out of spec.

As far as i can tell i need a 090 WUR, but apparently the 072 would be close in specs...i've looked around but can't find anywhere to buy this. (I'm not risking 500€ on ebay for a 35yr old 2nd hand part which probably has the same faults).

[boyt911sc]

Originally Posted by wreckah

Hi Tony, it was 11 ohms, i posted this some time ago. Should be higher, so it's out of spec.

As far as i can tell i need a 090 WUR, but apparently the 072 would be close in specs...i've looked around but can't find anywhere to buy this. (I'm not risking 500€ on ebay for a 35yr old 2nd hand part which probably has the same faults).

Jan,

That is what I was expecting to see. The resistance at 10~11 (Ohms) is out of spec and will always give you an erratic cold idle. Another PP member (Mike in FL) has exactly the same problem like yours. He has a newly rebuilt WUR-090 with 10 Ohms resistance. He sent it back to the rebuilder and came back with 10 Ohms again. Rebuilder insisted there was nothing wrong with the WUR-090. And this rebuilder is a well known company and an authorized Bosch rebuilder(?). Mike installed the second WUR and found the cold idle problem still persisted.

Now, I have this questionable WUR-090 and did the test yesterday. At 10 Ohms reading, it would be able to start and run the engine but would have this erratic cold idle. To fix this problem is to install a WUR has the correct heater resistance of 25~26 Ohms. Look at the picture below. That is what a good WUR-072/-090 should read when cold.



Do you know a friend visiting USA? I could lend you a WUR for you to test. You are not buying it. Just a loaner so you experience how a good working WUR contributes to your engine's performance. PM me.

Tony

[wreckah]

Hi Tony, that's a very nice offer, thanks. I'm gonna put some effort in finding something locally, and if that fails i'll pm you and maybe we can work something out. Big Porsche breaker's place is looking for 090's as we speak.

Do you know if it is normal to have air pressure under the valve covers if you put pressure onto the system (reverse vacuum cleaner through exhaust pipe)? Maybe it comes from the breather pipes? To me it seems weird that the airleak past the valve cover seal changes when turning the engine by hand...

[Vereeken]

FG Porsche ? Did not know they where still selling parts to individuals.

I can fix the heater element if it is not compeltely shot. But as I work at a leisurly pace your car will be off road for a while ;o)

[Vereeken]

Originally Posted by boyt911sc

Jan,







Tony

If you have ever wondered where all the WURs went to....

[wreckah]

Originally Posted by Vereeken

If you have ever wondered where all the WURs went to....

yapp, it's FG Porsche, they used to sponsor my big trip to China with the 69T, so i can still get parts there (bought targa roof spare piece couple of months ago)...i did not know they stopped b to c ?

i drive the thing quite regularly, but wouldn't mind a week or 2 delay...you think that's possible?

[Vereeken]

Ah you are the Carrera to China guy....

I think FG is using the parts for their own resto business.

I am not sure they can help you with a 090. But if you can get a bi-metal from them it is fairly easy to do. I have got 2 myself but I am attached to them ;o)

2 weeks should not be a problem.

We could mix the internals with the 072 you have today...and that is going to work. Pretty sure about that.

[wreckah]

yes, one of them, my buddy stayed in Cambodia

alright, will try to get the bi-metal.

[wreckah]

okay, just found an 090 in Germany, 25,3 ohms, should be here in a week or so, i will keep you guys updated, thanks, Jan

[Kemo]

I'm biting my nails on this one as I have a similar problem... Even after sending out both the WUR and the FD to CIS Flowtech for rebuild. I have not checked my OHMS across the WUR, but I will this week.
Thanks for taking the time to share your progress