Can I use this Decel Valve for a 1977 Carrera 3.0?

[Bill Jennings]

Hi,
I just bought a used decel valve sight unseen and it is different to the one on my 77 Carrera 3.0.
The one on my car has a small port on the top and a single large port on the bottom. I do not know the part number. Sorry about the poor picture but its hard to get my iPad in there!



The one I bought is a Bosch 0280160324 it has a small port on the top and two large ports on the bottom that are different sizes. The bottom middle port is about half the diameter of the one that is offset to the side.
Can I use this valve by plugging up one of the ports?
If so which one do I plug?
Final question how do I test this? I've read here that you can test a single port valve by sealing the top port with your finger and sucking on the bottom port but what do you do to test with two ports?.





Cheers
Bill

[T77911S]

there are 3 ports on yours as well.

the small port is to vacuum below the throttle plate. this opens the decel valve(DV) when you let off the gas. the other 2 just bypass around the throttle plate. the good thing about yours is it adjustable, and i like it because it is smaller and just looks better.

the one you bought is off an 80-83 CIS system. i suppose with enough hose you could make it work. not sure about mounting it. you may need to make a bracket.

[redstrosekNic]

Have you considered doing away with the decel valve? I think I am going to unplug the top hose of mine, plug the hose and the valve, and see how I like it.

BTW my decel valve looks like your car's.

[boyt911sc]

Bill,

I have some extra CIS parts like the decel valve you need. BTW, I was in Sydney last summer (winter over there) for over a month and went to Jervis Bay. What a beautiful place you have there. PM me your address and just take care of the shipping and handling expenses.

Tony

[T77911S]

tony, you might just swap parts. keeps your supply up.

[Bill Jennings]

Tony,

I've obviously not looked closely enough at my valve as I thought I only had one large port.
It is the great people on this forum that makes it the amazing community that it is.
I'm very happy to swap valves with you if you want it or offer it to someone else in need of it.
Tony, you have first call on it, I'll PM you.

This will be one well traveled valve though I had it sent here from Tucson.

Dustin,

I am currently running with the valve blocked off. Is it the valve on your 911S that looks like mine?

Cheers
Bill

[redstrosekNic]

Originally Posted by Bill Jennings

Tony,

I've obviously not looked closely enough at my valve as I thought I only had one large port.
It is the great people on this forum that makes it the amazing community that it is.
I'm very happy to swap valves with you if you want it or offer it to someone else in need of it.
Tony, you have first call on it, I'll PM you.

This will be one well traveled valve though I had it sent here from Tucson.

Dustin,

I am currently running with the valve blocked off. Is it the valve on your 911S that looks like mine?


Cheers
Bill

Yes, my decel valve looks like yours. If I may ask, why are you putting a new one on? Does your car exhibit annoying symptoms with the valve blocked off?

My car hangs at a higher rpm for longer than I would like it to, and I am afraid of messing something up trying to adjust it.

[boyt911sc]

Originally Posted by Bill Jennings

Tony,

I've obviously not looked closely enough at my valve as I thought I only had one large port.
It is the great people on this forum that makes it the amazing community that it is.
I'm very happy to swap valves with you if you want it or offer it to someone else in need of it.
Tony, you have first call on it, I'll PM you.

This will be one well traveled valve though I had it sent here from Tucson.

Dustin,

I am currently running with the valve blocked off. Is it the valve on your 911S that looks like mine?

Cheers
Bill

Bill,

PM me your address. I have too many spare decel valves (old & new styles) that I could not possibly use in my entire life. BTW, I'll be visit Jervis Bay next year and buy me a cup of coffee.

Tony

[Tidybuoy]

I may be wrong but I was under the impression that the valve you are showing is the "Auxillary Air Valve" (number #2 on the chart) and not the "Decel Valve" (number #9 on the chart).

Can anybody confirm?




Also, look at the parts discription on CIS Primer Site, and it shows two different functions for these parts.

CIS Primer for the Porsche 911

Vern

[Bill Jennings]

Tony,
You have a PM accepting your generous offer and one from me that is more than a coffee!

Dustin,
My CIS has had various symptoms which have changed since I started messing with it. Originally I had an intermittent hard hot start issue and the idle would hang up high at 2000 rpm when hot. I had to apply some clutch in second gear when stopping to bring it down to 1000 rpm where it would stay until the next time. I rerouted some vacuum lines and blocked off the decel valve and adjusted mixture and idle screw and now have low idle at start up from cold, and still have the intermittent idle hang up when hot. Hot start now cured. I have been advised by others here that I have a non standard CIS set up on this car. I have checked the fuel pressures and they were ok but haven't checked them recently. I set the mixture by putting it in the middle of too rich too lean even though I have a gunsen gas analyser. It read incredibly rich when I first tested using the gunsen and I'm not sure I trust it.

Cheers
Bill

[boyt911sc]

Originally Posted by Tidybuoy

I may be wrong but I was under the impression that the valve you are showing is the "Auxillary Air Valve" (number #2 on the chart) and not the "Decel Valve" (number #9 on the chart).

Can anybody confirm?




Also, look at the parts discription on CIS Primer Site, and it shows two different functions for these parts.

CIS Primer for the Porsche 911

Vern

Vern,

Bill J. showed the decel valve in his engine and a picture of the decel valve for '80-'83 SC. What you have is an illustration of the of the vacuum system prior to '80 CIS (Porsche) and that's what the '76-'79 CIS have. HTH.

Tony

[redstrosekNic]

Originally Posted by Bill Jennings

Tony,
You have a PM accepting your generous offer and one from me that is more than a coffee!

Dustin,
My CIS has had various symptoms which have changed since I started messing with it. Originally I had an intermittent hard hot start issue and the idle would hang up high at 2000 rpm when hot. I had to apply some clutch in second gear when stopping to bring it down to 1000 rpm where it would stay until the next time. I rerouted some vacuum lines and blocked off the decel valve and adjusted mixture and idle screw and now have low idle at start up from cold, and still have the intermittent idle hang up when hot. Hot start now cured. I have been advised by others here that I have a non standard CIS set up on this car. I have checked the fuel pressures and they were ok but haven't checked them recently. I set the mixture by putting it in the middle of too rich too lean even though I have a gunsen gas analyzer. It read incredibly rich when I first tested using the gunsen and I'm not sure I trust it.

Cheers
Bill

My Gunson gastester was dead on to what the car registered on a "real" exhaust analyzer. Be sure to thoroughly follow the cleaning process in the directions, as I've heard about people having accuracy problems after not cleaning them properly. Be sure to let the tester warm up properly as well.

Goodluck with your 911

[Bill Jennings]

Seeing as Tony has offered to pull me out of the hole that I dug for myself by buying the wrong valve I now have a spare Decel Valve for the 80-83 SC as shown above.

So if anyone needs one of these valves it's yours for the cost of the postage.

Cheers
Bill

[T77911S]

have you pulled the DV off. mine was full of oil and holding the idle hi. you can also adjust them. you can set the opening vacuum with the adjustment on top. i used a hand vacuum pump to test mine.

[Bill Jennings]

T77911s,

I've not tried that so will have a look.

Cheers

Bill

[hydrocrust]

Hi, Bill, If you still have that spare decel valve for the 80-83, I have an 82 with some issues that may be related to my DV, so I'd like to take you up on your offer. I'm at 95060, can PM you with details. best wishes, Andy

[Bill Jennings]

Looks like my decel valve will be on it's way to Santa Cruz shortly if the postage is reasonable enough for hydrocrust.
Cheers
Bill

[Bill Jennings]

Hydrocrust,

Just wondering..........

Did the valve ever arrive and did it fix your problem?

Cheers

Bill

[boyt911sc]

Bill,

Have you installed the decel valve? Any feedback?

Tony