Yet, another WUR question.

[bobswei]

This is on a '78 SC 3.0L. It's on a race car that's been sitting for a little over two years. It fires right up, runs for a second and dies, as if too lean. I figure it's the WUR not enriching when cold. I removed it and took it apart. First thing I notice is the heat element is 21R which, from my research, may be a little low? Then ohm test. (Two results). One, with my old meter that can't be set to certain range, I got 0.00. Then I tried my new meter and set it on 2K and I got .036. Then, I put it in the freezer for 10 minutes and got .033. The WUR part number ends in 033 which I can't match to a specific year, just "Porsche 911 3.0L". The diaphram is in good condtiiton. Also, in the second photo, should that white vacuum line be capped? It ran before, like that. Does this seem ok to others?
Thanks for any input.

[boyt911sc]

Bob,

Are you aware that you have the wrong WUR for your motor? Where is that braided hose hooked up to the side of WUR connected at the throttle body? To a vacuum port or to atmosphere? Keep us posted.

Tony

[bobswei]

Yea, I wasn't sure if it was correct since I found this:




But, I couldn't find a part number that matched to a '78. The part not connected, I guess you're referring to the part circled?



I will reinstall it today and find a vacuum line to connect. I thought, even if not correct for the motor, it could be "adjusted" to work.
I always seem to end up with old cars and mix matched parts.
I'll update, when I have a new result.
Thanks Tony!!

[boyt911sc]

Bob,

In the picture near intake runner #2, you could see a rubber hose with screw plugged in. Could you find out where that particular hose is connected? Or take a picture where it ends up. I am curious to know if it is connected to the TTV (Thermo Time Valve).

For WUR-033, vacuum line @ top, vent line @ side. Keep us posted.

Tony

[Paulporsche]

Tony,

Shouldn't Bob have a -045 WUR with the top hooked up to atmosphere and the bottom to a vacuum via the thermo valve?

With his -033 do you think he may be able to make it work with a little tweaking of the WUR? He lives in northern CA so he doesn't have to deal with extremely low temps...

[Paulporsche]

Control Pressure graph for -033 WUR, lower right

[boyt911sc]

Originally Posted by Paulporsche

Tony,

Shouldn't Bob have a -045 WUR with the top hooked up to atmosphere and the bottom to a vacuum via the thermo valve?

Paul,

You are correct that Bob should have a WUR-045. Or -069. Or -089. These are all vacuum assisted WUR’s with the same configuration except in the heater resistance values. However, in desperate time, a WUR-033 could be used instead. But the vacuum and vent connections should be reversed accordingly.

Tony

[Paulporsche]

045 Graph

[bobswei]

Positive update: I did a few things at the same time so not sure what made the biggest improvement. But, I re-assembled the WUR, I tighten the adjusting nut (make richer), added the vacuum line (previously plugged) to the top white fitting, disconnected the lower vacuum line, added fresh gas to the tank. Now, on the third try, I got it started and idling. For the first two minutes or so, if you touch the gas pedal, it wanted to die. After that, I could slowly ad throttle and another 30 seconds, it revved like a new engine.
Tony, the photos show, the previous plugged hose is connected to the front (facing the front of the car), of the throttle body and the hose that was connected to the lower point, goes into the throttle body that faces rearward (towards back of car). Some of the graphs that have been posted, may be a little advanced for me, who feels lucky to get an ohm reading. I will try and get the car into my garage, in the next week or so. (It's in a portable garage in the back yard now). Then, I'll try and get my fuel pressure gauge on it and see if I can dial it in a little better for start ups.
Thanks for all the help and input. Some great advice and knowledgably people on here.

[Paulporsche]

As Tony said, you may be able to use that WUR. On a -033 the side vent should be open to either a high port on the throttle body or open to the air, which you have done. The top one should go to a lower TB port, which also looks like you have done.

Now you need to verify your fuel and control pressures with a fuel gauge to see if they are within range as shown in the graphs I posted.

BTW which adjustment nut did you tighten that you said richened the mixture?

[SkiVT]

Looks like you have no ttv on vacuum line between wur and throttle body. Your line off top of wur is the purple line path in this diagram.

[boyt911sc]

Originally Posted by bobswei

Positive update:

Bob,

Your engine is missing some critical CIS components like decel valve, thermo time valve, etc. I will be more than happy to lend you what you need and no obligation to buy. I want you to experience what is like having the right parts in your motor. You have 3 weeks to decide before I go for a 4-week vacation in November. Or wait after my return in December. There is also a ‘78 SC Targa in the garage for 30 years now.

BTW, what is that pink colored tube for?

Tony

[bobswei]

"BTW which adjustment nut did you tighten that you said richened the mixture?"
- Paul, The modification some do to the top of the WUR to raise and lower the metallic strip inside. (circled in red). I believe, tightening richens fuel and loosening and tapping down the bolt, leans. Yea, I have a cheap Harbor Freight fuel pressure set I'll put on it, (if there's connections that fit). The last car, none of the connectors with the kit worked. I had to make my own.
Skivt - Looks like you and Tony are spotting the same things. From your diagram, the part #4 would explain why, it takes a minute before you can give it some throttle.

"BTW, what is that pink colored tube for?" - Tony, the pink (red) tube is a wire. If I recall correctly. I couldn't get power to go through the harness to the enrichment valve. So I ran a separate wire through a switch on the dash, so when warm, I could turn it off for starts. Since it's a race car, I only used the wires, from the harness, that were necessary for the motor. Tony, that's very kind of you to offer parts. Once I get it in the garage and do my adjusting, I'll see if I need to go further. It ran pretty good 2.5 years ago. But I do recall, cold starts were less than perfect. Thank you!!

I will try and get it in the garage, this week. Currently, every time I need a tool, I go through the house, into the garage, back through the house, into the backyard. And I forget a lot of tools. I currently have a 914 in the garage, I'm trying to sort out and run good, then move it to the backyard.

Thanks for all the additional help and posting the graphs and diagrams. A real help....