Home  |  Forums  |  914 Info  |  Blogs
 
914World.com - The fastest growing online 914 community!
 
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG. This site is not affiliated with Porsche in any way.
Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners.
 

Welcome Guest ( Log In | Register )

3 Pages V  1 2 3 >  
Reply to this topicStart new topic
> Deceleration Valve
Ian Stott
post Dec 30 2019, 07:41 AM
Post #1


Senior Member
***

Group: Members
Posts: 907
Joined: 28-January 08
From: Moncton/Canada
Member No.: 8,635
Region Association: Canada



This is a very difficult to get item to get! Many have said soaking the existing one in kerosene for a few days will do the trick, have not done that yet as I am still trying to track down a new one. Wondering what the success rate has been with soaking it in kerosene, also wondering would WD 40 do the same thing. Would hate to ruin the one I have, which is original to the car!

Ian Stott
Moncton
Canada
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
bdstone914
post Dec 30 2019, 08:07 AM
Post #2


bdstone914
****

Group: Members
Posts: 4,724
Joined: 8-November 03
From: Riverside CA
Member No.: 1,319



@Ian Stott

For L jet or D jet ?
Can you post the number on yours?
Bruce
User is online!Profile CardPM
Go to the top of the page
+Quote Post
Ian Stott
post Dec 30 2019, 09:07 AM
Post #3


Senior Member
***

Group: Members
Posts: 907
Joined: 28-January 08
From: Moncton/Canada
Member No.: 8,635
Region Association: Canada



QUOTE(bdstone914 @ Dec 30 2019, 10:07 AM) *

@Ian Stott

For L jet or D jet ?
Can you post the number on yours?
Bruce

Bosch 022 133551
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Ian Stott
post Dec 31 2019, 11:19 AM
Post #4


Senior Member
***

Group: Members
Posts: 907
Joined: 28-January 08
From: Moncton/Canada
Member No.: 8,635
Region Association: Canada



I thought I would bring this back to the top, as I have not had any response to the soaking the valve in kerosene or WD 40 suggestions. Maybe my title was misleading in that many saw it as looking for a deceleration valve, of course I am looking for one but just as important is the question has anyone does this and what were the results?

Thanks!

Ian Stott
Moncton
Canada
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
timothy_nd28
post Dec 31 2019, 11:54 AM
Post #5


Advanced Member
****

Group: Members
Posts: 2,299
Joined: 25-September 07
From: IN
Member No.: 8,154
Region Association: Upper MidWest



I was alittle confused reading what you were doing with the decel valve. I haven't heard of people soaking a decel valve before, maybe soaking a aux air valve. I wouldn't think there's much inside a decel valve other than a large rubber diaphragm.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Highland
post Dec 31 2019, 03:36 PM
Post #6


Senior Member
***

Group: Members
Posts: 529
Joined: 8-August 11
From: San Diego, CA
Member No.: 13,418
Region Association: Southern California



Have you tried turning the adjustment screw to loosen things up then readjusting the decel valve to open at the vacuum setting you want? Maybe blow some air in there to clean out any debris.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
dr914@autoatlanta.com
post Dec 31 2019, 04:24 PM
Post #7


914 Guru
*****

Group: Members
Posts: 8,103
Joined: 3-January 07
From: atlanta georgia
Member No.: 7,418
Region Association: None



we try the wd40 first then buy a used one
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
914werke
post Dec 31 2019, 05:29 PM
Post #8


"I got blisters on me fingers"
**********

Group: Members
Posts: 10,976
Joined: 22-March 03
From: USofA
Member No.: 453
Region Association: Pacific Northwest



Attached Image
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Ian Stott
post Jan 1 2020, 09:45 AM
Post #9


Senior Member
***

Group: Members
Posts: 907
Joined: 28-January 08
From: Moncton/Canada
Member No.: 8,635
Region Association: Canada



QUOTE(dr914@autoatlanta.com @ Dec 31 2019, 06:24 PM) *

we try the wd40 first then buy a used one

Do you have one I could purchase?

Ian Stott
Moncton
Canada
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
cary
post Jan 1 2020, 11:04 AM
Post #10


Advanced Member
****

Group: Members
Posts: 3,900
Joined: 26-January 04
From: Sherwood Oregon
Member No.: 1,608
Region Association: Pacific Northwest



I have 2 soaking in kerosene right now. I'll drain, dry and let you know the outcome.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
rjames
post Jan 1 2020, 12:24 PM
Post #11


I'm made of metal
****

Group: Members
Posts: 4,150
Joined: 24-July 05
From: Shoreline, WA
Member No.: 4,467
Region Association: Pacific Northwest




(IMG:style_emoticons/default/popcorn[1].gif)
I’ll be interested in your results.
I’ve got one that leaks but only after driving the car for 15-20 minutes or so. I’d like to keep mine connected as I’ve read they help reduce strain on the MPS but mine is disconnected for now.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Ian Stott
post Jan 2 2020, 12:12 PM
Post #12


Senior Member
***

Group: Members
Posts: 907
Joined: 28-January 08
From: Moncton/Canada
Member No.: 8,635
Region Association: Canada



QUOTE(cary @ Jan 1 2020, 01:04 PM) *

I have 2 soaking in kerosene right now. I'll drain, dry and let you know the outcome.


Thanks, I will wait to hear from you!

Ian Stott
Moncton
Canada
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Rand
post Jan 2 2020, 01:42 PM
Post #13


Cross Member
*****

Group: Members
Posts: 7,409
Joined: 8-February 05
From: OR
Member No.: 3,573
Region Association: None



I'm curios if you understand why you need it? Why do you think you do?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Ian Stott
post Jan 3 2020, 06:05 AM
Post #14


Senior Member
***

Group: Members
Posts: 907
Joined: 28-January 08
From: Moncton/Canada
Member No.: 8,635
Region Association: Canada



QUOTE(Rand @ Jan 2 2020, 03:42 PM) *

I'm curios if you understand why you need it? Why do you think you do?


According to the mechanic working on my car it controls the vacuum, so when not working you can have backfiring on deceleration, which I have. Also it is not possible to set the idle correctly with it being plugged. I am sure more knowledgeable people can explain the need for it better than me! I am also pretty confident it is there for a reason or Porsche would have not put it in the car.
My mechanic is an ASE from Belgium, has worked on these cars before emigrating to Canada; until I found him I was on the verge of switching to aftermarket fuel injection.

Ian Stott
Moncton
Canada
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
GregAmy
post Jan 3 2020, 07:10 AM
Post #15


Advanced Member
****

Group: Members
Posts: 2,406
Joined: 22-February 13
From: Middletown CT
Member No.: 15,565
Region Association: North East States



It doesn't "control the vacuum" (if I understand you correctly); it uses manifold vacuum to open itself, to add un-throttled air to the intake to lean it the mixture on decel to reduce backfire (and excessive emissions) due to a rich mixture.

Modern EFI simply backs off the injector pulse (or shuts off the injectors entirely) when the throttle is closed (as indicated by the TPS) and on engine over-run to lean out the mixture. For whatever reason, D-Jet was not able to do that back then (or maybe they didn't think of it?)

Testing the decel valve is fairly straightforward. With no vacuum on the port, the valve should be closed and you can't blow through it. Adding a vacuum via a Mity-Vac and the valve should open and you can blow through it. As I recall the desired setting for that cutover is 17mmHg?

If you can blow through it when it's off the car, and/or cannot blow through it with vacuum on it, then it's bad and/or out of adjustment. I wouln'dt be surprised if a prior owner danked around with the adjustment...

If it works fine but the cutover vacuum is either too high or too low, then it can be adjusted via that locknut and screw to ~17mmHg.

What are your current symptoms when testing in this manner?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Ian Stott
post Jan 3 2020, 07:28 AM
Post #16


Senior Member
***

Group: Members
Posts: 907
Joined: 28-January 08
From: Moncton/Canada
Member No.: 8,635
Region Association: Canada



QUOTE(GregAmy @ Jan 3 2020, 09:10 AM) *

It doesn't "control the vacuum" (if I understand you correctly); it uses manifold vacuum to open itself, to add un-throttled air to the intake to lean it the mixture on decel to reduce backfire (and excessive emissions) due to a rich mixture.

Modern EFI simply backs off the injector pulse (or shuts off the injectors entirely) when the throttle is closed (as indicated by the TPS) and on engine over-run to lean out the mixture. For whatever reason, D-Jet was not able to do that back then (or maybe they didn't think of it?)

Testing the decel valve is fairly straightforward. With no vacuum on the port, the valve should be closed and you can't blow through it. Adding a vacuum via a Mity-Vac and the valve should open and you can blow through it. As I recall the desired setting for that cutover is 17mmHg?

If you can blow through it when it's off the car, and/or cannot blow through it with vacuum on it, then it's bad and/or out of adjustment. I wouln'dt be surprised if a prior owner danked around with the adjustment...

If it works fine but the cutover vacuum is either too high or too low, then it can be adjusted via that locknut and screw to ~17mmHg.

What are your current symptoms when testing in this manner?

Will talk to the mechanic about what you have posted, thanks so much for the info, will keep you posted!

Ian Stott

User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Mark Henry
post Jan 3 2020, 08:56 AM
Post #17


that's what I do!
***************

Group: Members
Posts: 20,065
Joined: 27-December 02
From: Port Hope, Ontario
Member No.: 26
Region Association: Canada



QUOTE(bdstone914 @ Dec 30 2019, 09:07 AM) *

@Ian Stott

For L jet or D jet ?
Can you post the number on yours?
Bruce


Ljet on a 2056 engine with a #73 WEB cam.

Ian did you get your starting issue sorted out?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Ian Stott
post Jan 3 2020, 11:28 AM
Post #18


Senior Member
***

Group: Members
Posts: 907
Joined: 28-January 08
From: Moncton/Canada
Member No.: 8,635
Region Association: Canada



QUOTE(Mark Henry @ Jan 3 2020, 10:56 AM) *

QUOTE(bdstone914 @ Dec 30 2019, 09:07 AM) *

@Ian Stott

For L jet or D jet ?
Can you post the number on yours?
Bruce


Ljet on a 2056 engine with a #73 WEB cam.

Ian did you get your starting issue sorted out?

Yes we did Mark, now I can start the car and I let it warm up as it stumbles until I get close to operating temp, then it works nice, pulls strong and smooth. Idle is good if I have been just around town, if I have run it at {hwy speeds plus} the idle is too low and can stall til engine cools a bit. I have never even got close to the m on the temp gauge just so you know I am not abusing it!Thanks to the new heads I think, supposed to run cooler with those.

Ian

User is offlineProfile CardPM
Go to the top of the page
+Quote Post
bdstone914
post Jan 3 2020, 11:37 AM
Post #19


bdstone914
****

Group: Members
Posts: 4,724
Joined: 8-November 03
From: Riverside CA
Member No.: 1,319



QUOTE(Ian Stott @ Jan 3 2020, 11:28 AM) *

QUOTE(Mark Henry @ Jan 3 2020, 10:56 AM) *

QUOTE(bdstone914 @ Dec 30 2019, 09:07 AM) *

@Ian Stott

For L jet or D jet ?
Can you post the number on yours?
Bruce


Ljet on a 2056 engine with a #73 WEB cam.

Ian did you get your starting issue sorted out?

Yes we did Mark, now I can start the car and I let it warm up as it stumbles until I get close to operating temp, then it works nice, pulls strong and smooth. Idle is good if I have been just around town, if I have run it at {hwy speeds plus} the idle is too low and can stall til engine cools a bit. I have never even got close to the m on the temp gauge just so you know I am not abusing it!Thanks to the new heads I think, supposed to run cooler with those.

Ian




I checked but did not find that I have any decel valves.
Found this on Brad Anders site

Porsche number 022 133 551 Bosch 0 280 160 102 1.7L 1972 - 1973

1970 -1971 1.7L 914's didn't have a decel valve, because their ECU cut off the fuel flow on overrun.

Bruce
User is online!Profile CardPM
Go to the top of the page
+Quote Post
Ian Stott
post Jan 3 2020, 12:12 PM
Post #20


Senior Member
***

Group: Members
Posts: 907
Joined: 28-January 08
From: Moncton/Canada
Member No.: 8,635
Region Association: Canada



QUOTE(bdstone914 @ Jan 3 2020, 01:37 PM) *

QUOTE(Ian Stott @ Jan 3 2020, 11:28 AM) *

QUOTE(Mark Henry @ Jan 3 2020, 10:56 AM) *

QUOTE(bdstone914 @ Dec 30 2019, 09:07 AM) *

@Ian Stott

For L jet or D jet ?
Can you post the number on yours?
Bruce


Ljet on a 2056 engine with a #73 WEB cam.

Ian did you get your starting issue sorted out?

Yes we did Mark, now I can start the car and I let it warm up as it stumbles until I get close to operating temp, then it works nice, pulls strong and smooth. Idle is good if I have been just around town, if I have run it at {hwy speeds plus} the idle is too low and can stall til engine cools a bit. I have never even got close to the m on the temp gauge just so you know I am not abusing it!Thanks to the new heads I think, supposed to run cooler with those.

Ian




I checked but did not find that I have any decel valves.
Found this on Brad Anders site

Porsche number 022 133 551 Bosch 0 280 160 102 1.7L 1972 - 1973

1970 -1971 1.7L 914's didn't have a decel valve, because their ECU cut off the fuel flow on overrun.

Bruce

Thanks for checking!

Ian

User is offlineProfile CardPM
Go to the top of the page
+Quote Post

3 Pages V  1 2 3 >
Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



- Lo-Fi Version Time is now: 6th December 2024 - 05:56 AM