| Author |
Message |
supdave66
Samba Member
Joined: March 11, 2004
Posts: 126
|
 Posted: Mon Oct 15, 2018 8:11 pm Post subject: 34 pict-3 will not idle |
 |
|
I am at my wits end. I have tried everything I can not get my bug to idle when it’s warmed up. It runs fine until the choke kicks off, then nothing. Everything was running great a month ago and then it started stalling at stop signs and red lights. Nothing has changed and only thing I have done, was change the fuel lines.
This what I have tried.
Rebuilt carb- new everything, even float.
Checked timing
Adjusted valves
Checked for air leaks
Need the VW gods on this one. |
|
| Back to top |
|
 |
Cusser
Samba Member
Joined: October 02, 2006
Posts: 31379
Location: Hot Arizona
|
| Posted: Mon Oct 15, 2018 9:05 pm Post subject: Re: 34 pict-3 will not idle |
|
|
| supdave66 wrote: |
| I am at my wits end. I have tried everything I can not get my bug to idle when it’s warmed up. It runs fine until the choke kicks off, then nothing. |
Adjust the choke position when the engine is at operating temperature.
_________________
1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297 |
|
| Back to top |
|
|
bnam
Samba Member
Joined: July 02, 2006
Posts: 2936
Location: El Dorado Hills CA/ Bangalore, India
|
| Posted: Mon Oct 15, 2018 9:12 pm Post subject: Re: 34 pict-3 will not idle |
|
|
Did you try cleaning the idle jet again?
_________________
1971 1302LS Convertible (RHD) owned since '74
Click to view image
1965 Karmann Ghia Coupe - under restoration
1966 Fiat 1500 Cabrio (with 1600 Twin cam)
1952 Citroen TA 11BL |
|
| Back to top |
|
|
supdave66
Samba Member
Joined: March 11, 2004
Posts: 126
|
| Posted: Tue Oct 16, 2018 3:23 am Post subject: Re: 34 pict-3 will not idle |
|
|
| Idle jet has been cleaned twice now. The first time I took the carb off that is all I did, clean everything out real good. Second time I did a complete rebuild and hit all the jets again. I also played with the choke did nothing. |
|
| Back to top |
|
|
vamram 
Samba Member
Joined: March 08, 2012
Posts: 7304
Location: NOVA
|
| Posted: Tue Oct 16, 2018 3:51 am Post subject: Re: 34 pict-3 will not idle |
|
|
Is the carb a German Solex? Bocar? Chinese knock-off? How old is the carb? You said you checked for air leaks - did you find any?
_________________
Eventually, "we are what we pretend to be.’”
Give peace a chance - Stop Russian-Soviet Aggression!!
'74 Super 9/16 - present, in refurb process.
'73 Super - 6/18 - Present - Daily Driver!
'75 Super Le Grande...waiting it's turn in line behind '74.
Click to view image
Save the Supers!! |
|
| Back to top |
|
|
ashman40
Samba Member
Joined: February 16, 2007
Posts: 15987
Location: North Florida, USA
|
| Posted: Tue Oct 16, 2018 4:23 am Post subject: Re: 34 pict-3 will not idle |
|
|
More details pls....
| supdave66 wrote: |
This what I have tried.
Rebuilt carb- new everything, even float. [Did this "rebuild" include soaking the carb body overnight and blowing all passages clear with 90psi compressed air?]
Checked timing [What make/model# distributor are you running? How did you set the timing (static/idle/total advance; hoses connected or plugged)?]
Adjusted valves [To what gap?]
Checked for air leaks [See below...] |
My first guess from your descriptions is you have a vacuum leak somewhere. The leak is being masked while the choke is ON. When the choke turns OFF the mixture goes lean and you get rough idle.
To confirm it is a lean condition....
Warm up the engine until the choke is OFF.
Use the fast idle cam to keep the engine idling. Rotate the cam just enough so the engine remains running for this test.
Place your flat hand with closed fingers over the top of the carb, sealing the opening. Cover 50% of the opening.
Slowly slide your flat hand over the carb opening closing off more and more of the opening. This will begin to choke off the air flow.
Normally, as you start to restrict the airflow the idle rpms will slowly drop. It is the same as closing off the air-fuel mixture flowing into the engine. But if you find that the engine idle smooths out or goes UP then you have found a lean running condition (usually caused by a vacuum leak). Blocking off the air flow causes the mixture to go rich. But if the mixture is already lean from an air leak you end up balancing the mixture closer to ideal and the idle rises.
If this test suggests you have a leak try the following test to see if your throttle shaft bores are leaking....
With the engine idling, break out the carb cleaner and with the red straw attached spray just to the right of the red lines. The red lines highlight the throttle shaft flanges. To the right of the red line is the narrow gap between the shaft flange and the open end of the carb throttle bore. Focus your spray at this gap while you listen for the idle to change. You might even try pulling the throttle arm to the left to open the gap more.
Do the same to the opposite side of the carb.
These bores wear out over time and open a path for air to leak into the intake. Normal spraying around the carb will NOT highlight the leak. You often need to focus the spray with the straw and purposely hit the gap for any change to be heard.
If this causes the idle to change (up or down)... you have a vacuum leak at your throttle shaft. You will need to send your carb out to have the shaft bores "rebushed" to repair the worn bores.
_________________
AshMan40
---------------------------
'67 Beetle #1 {project car that never made it to the road  }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!} |
|
| Back to top |
|
|
supdave66
Samba Member
Joined: March 11, 2004
Posts: 126
|
| Posted: Tue Oct 16, 2018 10:53 am Post subject: Re: 34 pict-3 will not idle |
|
|
Very nice write up. Thank you
I will give it a shot tonight |
|
| Back to top |
|
|
71whitewesty
Samba Member
Joined: February 25, 2010
Posts: 1544
Location: oregon
|
| Posted: Tue Oct 16, 2018 11:11 am Post subject: Re: 34 pict-3 will not idle |
|
|
My two cents and I just had the same problem with it idleing rough after warm up and wanting to stall at stops signs etc. my issue was a barley noticeable vacuum leak at the dp manifold gasket. Replaced the gasket and it’s good as new again.
_________________
71 Westy 1600 DP, all stock Bus 1
1970's Snow Trac 1600 SP (sold 12/2016)
1968 Tucker sno cat, sold 2021
1969 Tucker Sno cat 542
2017 VW Alltrac
71 tin top stock 1600 DP (project but runs)
Twin 71 White Westy, Bus 2, that I pulled from a 15 year slumber in a dry eastern WA field in 2015.
1966 Sundial Camper "Boomer" |
|
| Back to top |
|
|
JaimeReyes
Samba Member
Joined: May 30, 2018
Posts: 165
Location: San diego CA
|
| Posted: Tue Oct 16, 2018 4:28 pm Post subject: Re: 34 pict-3 will not idle |
|
|
| 71whitewesty wrote: |
| My two cents and I just had the same problem with it idleing rough after warm up and wanting to stall at stops signs etc. my issue was a barley noticeable vacuum leak at the dp manifold gasket. Replaced the gasket and it’s good as new again. |
i had this same experience but my volume control screw had a torn o ring so air was getting in. replaced the o ring and all was well again. |
|
| Back to top |
|
|
bnam
Samba Member
Joined: July 02, 2006
Posts: 2936
Location: El Dorado Hills CA/ Bangalore, India
|
| Posted: Tue Oct 16, 2018 7:10 pm Post subject: Re: 34 pict-3 will not idle |
|
|
Timing, dwell all checked?
_________________
1971 1302LS Convertible (RHD) owned since '74
Click to view image
1965 Karmann Ghia Coupe - under restoration
1966 Fiat 1500 Cabrio (with 1600 Twin cam)
1952 Citroen TA 11BL |
|
| Back to top |
|
|
supdave66
Samba Member
Joined: March 11, 2004
Posts: 126
|
| Posted: Tue Oct 16, 2018 7:17 pm Post subject: Re: 34 pict-3 will not idle |
|
|
| My manifold gaskets look good, but was going to try that just to check that off. I did put a new rubber o-ring on the volume control screw, did not help. |
|
| Back to top |
|
|
supdave66
Samba Member
Joined: March 11, 2004
Posts: 126
|
| Posted: Tue Oct 16, 2018 7:19 pm Post subject: Re: 34 pict-3 will not idle |
|
|
| bnam wrote: |
| Timing, dwell all checked? |
Timing has been checked |
|
| Back to top |
|
|
supdave66
Samba Member
Joined: March 11, 2004
Posts: 126
|
| Posted: Tue Oct 16, 2018 7:22 pm Post subject: Re: 34 pict-3 will not idle |
|
|
| bnam wrote: |
| Timing, dwell all checked? |
Electronic ignition
Ran great last month, problem just started |
|
| Back to top |
|
|
wcfvw69
Samba Purist
Joined: June 10, 2004
Posts: 13389
Location: Arizona
|
| Posted: Tue Oct 16, 2018 8:37 pm Post subject: Re: 34 pict-3 will not idle |
|
|
Did you measure your float height? Most rebuild kits for the 34-3 have the wrong washer under the needle shut off valve. This measurement is critical for these 34-3 carbs.
Also, how did you adjust the carb? Many people get stuck in the 2.5 turns open from fully closed. Sometimes the engine needs more so you open the volume screw up to 3 turns out or more.
I've found the only way to really clean these carbs is to put them in an ultrasonic parts cleaner. The vibration removes all the junk from the tiny passages inside them. I had a carb do the same thing you're experiencing. I soaked it in Berrymans, blew the passages out with carb cleaner. Only after I fully disassembled it and cleaned it in the sonic cleaner, did it clean it out and it would idle off choke.
http://www.vw-resource.com/34pict3.html
Here's a good write up to double check your adjustments.
_________________
Contact me at [email protected]
Follow me on instagram @sparxwerksllc
Decades of VW and VW parts restoration experience.
The Samba member since 2004.
**Now rebuilding throttle bodies for VW's and Porsche's**
**Restored German Bosch distributors for sale or I can restore yours**
**Restored German Pierburg fuel pumps for sale or I can restore yours**
**Restored Porsche fuel pumps or I can restore yours**
**Restored Porsche distributors or I can restore yours** |
|
| Back to top |
|
|
supdave66
Samba Member
Joined: March 11, 2004
Posts: 126
|
| Posted: Wed Oct 17, 2018 7:43 pm Post subject: Re: 34 pict-3 will not idle |
|
|
| ashman40 wrote: |
More details pls....
| supdave66 wrote: |
This what I have tried.
Rebuilt carb- new everything, even float. [Did this "rebuild" include soaking the carb body overnight and blowing all passages clear with 90psi compressed air?]
Checked timing [What make/model# distributor are you running? How did you set the timing (static/idle/total advance; hoses connected or plugged)?]
Adjusted valves [To what gap?]
Checked for air leaks [See below...] |
My first guess from your descriptions is you have a vacuum leak somewhere. The leak is being masked while the choke is ON. When the choke turns OFF the mixture goes lean and you get rough idle.
To confirm it is a lean condition....
Warm up the engine until the choke is OFF.
Use the fast idle cam to keep the engine idling. Rotate the cam just enough so the engine remains running for this test.
Place your flat hand with closed fingers over the top of the carb, sealing the opening. Cover 50% of the opening.
Slowly slide your flat hand over the carb opening closing off more and more of the opening. This will begin to choke off the air flow.
Normally, as you start to restrict the airflow the idle rpms will slowly drop. It is the same as closing off the air-fuel mixture flowing into the engine. But if you find that the engine idle smooths out or goes UP then you have found a lean running condition (usually caused by a vacuum leak). Blocking off the air flow causes the mixture to go rich. But if the mixture is already lean from an air leak you end up balancing the mixture closer to ideal and the idle rises.
If this test suggests you have a leak try the following test to see if your throttle shaft bores are leaking....
With the engine idling, break out the carb cleaner and with the red straw attached spray just to the right of the red lines. The red lines highlight the throttle shaft flanges. To the right of the red line is the narrow gap between the shaft flange and the open end of the carb throttle bore. Focus your spray at this gap while you listen for the idle to change. You might even try pulling the throttle arm to the left to open the gap more.
Do the same to the opposite side of the carb.
These bores wear out over time and open a path for air to leak into the intake. Normal spraying around the carb will NOT highlight the leak. You often need to focus the spray with the straw and purposely hit the gap for any change to be heard.
If this causes the idle to change (up or down)... you have a vacuum leak at your throttle shaft. You will need to send your carb out to have the shaft bores "rebushed" to repair the worn bores. |
Loves this write up. There is a lot of good information. Thanks Brother
This what I found so far.
With engine warmed up and on the fast idle cam ( great idea). I sprayed carb cleaner on throttle shaft and rubber manifold boots. Idle did go up on both spots even though boots looked great. I decided to replace boots first. When I took everything apart I could see why they leaked. The aluminum manifolds had oxidized where the boot goes. I did get everything back on, but ran out of time to test. I will button everything up tomorrow and keep you posted. |
|
| Back to top |
|
|
tisius
Samba Member
Joined: July 11, 2011
Posts: 1570
Location: Rotterdam,NL (+Chicago,IL)
|
| Posted: Tue May 19, 2020 7:10 am Post subject: Re: 34 pict-3 will not idle |
|
|
so what happened, did it take you this long to test it further?  
I hope you resolved it.
Just curious to hear what the cause was, because I have a similar issue going on and I suspect an air leak on the throttle shaft.
Thanks in advance for your explanation!
_________________
drive it like you just robbed the bank
you don't have to be crazy to be into VW's, but it sure helps!!
.... if it ain't dutch, it ain't much! |
|
| Back to top |
|
|
mdwman
Samba Member
Joined: June 11, 2005
Posts: 241
Location: Tennessee
|
| Posted: Mon May 25, 2020 2:30 pm Post subject: Re: 34 pict-3 will not idle |
|
|
I'd like to bump this up; interested to hear the results.
_________________
MDWMAN |
|
| Back to top |
|
|
|
