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J1 Samba Member
Joined: February 10, 2014 Posts: 698 Location: SoCal
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Posted: Sun Apr 13, 2014 11:45 pm Post subject: What is causing my high idle? |
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Thx for those willing to read thru this.
Here's how the high idle started:
- Valve clearance adjusted
- Oil changed
- Compression tested
- Spark plugs gapped
- Belt tension adjusted
- Then I started messing with the carb and the timing. Hard to say exactly what I did because I was playing with both simultaneously.
So now min idle is a sputter-y 1000, warmed up, at fully open choke. So then:
- Pulled carb & cleaned. Not rebuild or new gaskets, just cleaned (took apart float, volume control screw, bypass screw, and that faucet-looking thingy).
- Replaced volume control screw o-ring since it was shredded to nothing (slightly tight fit).
- Choke adjusted
- Throttle lever screw and cable adjusted so it's at lowest possible point.
- Doesn't appear to be any leaks on carb.
Maybe relevant
- Volume control screw with new o-ring doesn't appear to impact idle
- 34 PICT 3
- 009, electronic ignition
I know I could just send the carb in for a full rebuild, but it seemed to be working fine before I messed with it, plus I would've guessed most carb problems cause LOW idle.
So what did I do wrong? Is it likely the carb or could it be something else? _________________ 1971 Ghia coupe. Assume I know nothing and you'll be pretty darn close to the truth. |
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Woreign Samba Member
Joined: June 04, 2006 Posts: 2841 Location: Crestview FL
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Posted: Mon Apr 14, 2014 6:05 am Post subject: |
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You might want to start by re-adjusting the carb. Here are some easy to follow steps: http://www.vw-resource.com/34pict3.html
Timing and dwell can also affect your idle speed, so be sure to double-check these as well. |
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J1 Samba Member
Joined: February 10, 2014 Posts: 698 Location: SoCal
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Posted: Mon Apr 14, 2014 10:42 am Post subject: |
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Yes, I've gone thru those steps. The 2.5 turns and all. Thx.
For those who understandably don't want to read thru all of the above, I think my bottom line question is "what are some common causes of HIGH idle?" I realize there may be too many variables which is why I thought providing some details of what I did may narrow down the field. Thx. _________________ 1971 Ghia coupe. Assume I know nothing and you'll be pretty darn close to the truth. |
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kingkarmann Samba Member
Joined: November 05, 2003 Posts: 4105
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Posted: Mon Apr 14, 2014 11:08 am Post subject: |
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Woreign wrote: |
You might want to start by re-adjusting the carb. Here are some easy to follow steps: http://www.vw-resource.com/34pict3.html
Timing and dwell can also affect your idle speed, so be sure to double-check these as well. |
How are you checking timing?
Are you using a timing light?
Are you checking both static and dynamic timing? _________________ "Depression is a malfunction of the instrument we use to determine reality.”
Mike Gerson
What is your "Bespoke Reality"? |
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c21darrel Samba Member
Joined: January 22, 2009 Posts: 8206 Location: San Dimas
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J1 Samba Member
Joined: February 10, 2014 Posts: 698 Location: SoCal
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Posted: Mon Apr 14, 2014 11:33 am Post subject: |
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kingkarmann wrote: |
How are you checking timing?
Are you using a timing light?
Are you checking both static and dynamic timing? |
Dynamic, with timing light. Have not done static.
But I'm not even worried about timing yet since I'm trying to first get my idle down to 850 so that I can then move on to setting timing correctly. _________________ 1971 Ghia coupe. Assume I know nothing and you'll be pretty darn close to the truth. |
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kingkarmann Samba Member
Joined: November 05, 2003 Posts: 4105
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Posted: Mon Apr 14, 2014 11:35 am Post subject: |
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Also, your pertronix 009 distributor is timed to 30-32 degrees of advance after top dead center AFTC (which by the way, is about full advance for the 009) at 3000 rpm. This can really only be accurately done with a timing light. The advance at idle should fall somewhere around 5-7.5 degrees before top dead center or BTDC.
You will notice as you rotate the 009 the the rpms change. You might be initially advanced too far thus explaining the high idle.
After you dial in the 009 timing then (if you need too) you can move on the carb.
Also with a pertronix or other electronic static timing isn't really done. _________________ "Depression is a malfunction of the instrument we use to determine reality.”
Mike Gerson
What is your "Bespoke Reality"? |
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J1 Samba Member
Joined: February 10, 2014 Posts: 698 Location: SoCal
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Posted: Mon Apr 14, 2014 12:24 pm Post subject: |
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kingkarmann wrote: |
Also, your pertronix 009 distributor is timed to 30-32 degrees of advance after top dead center AFTC (which by the way, is about full advance for the 009) at 3000 rpm. This can really only be accurately done with a timing light. The advance at idle should fall somewhere around 5-7.5 degrees before top dead center or BTDC. |
Slap to forehead! The bit of info I was missing is that 009 is timed differently and I do see lots of posts about that. But I see some inconsistencies in ATDC vs BTDC... so let me just clarify...
Is this correct?
First, at 3000 rpm: 30-32 degrees BTDC (mark to the right of TDC)
Then at idle: it should fall around 5-7.5 degrees BTDC (mark to the right of TDC) _________________ 1971 Ghia coupe. Assume I know nothing and you'll be pretty darn close to the truth. |
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kingkarmann Samba Member
Joined: November 05, 2003 Posts: 4105
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Posted: Mon Apr 14, 2014 1:15 pm Post subject: |
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Jawon wrote: |
kingkarmann wrote: |
Also, your pertronix 009 distributor is timed to 30-32 degrees of advance after top dead center AFTC (which by the way, is about full advance for the 009) at 3000 rpm. This can really only be accurately done with a timing light. The advance at idle should fall somewhere around 5-7.5 degrees before top dead center or BTDC. |
Slap to forehead! The bit of info I was missing is that 009 is timed differently and I do see lots of posts about that. But I see some inconsistencies in ATDC vs BTDC... so let me just clarify...
Is this correct?
First, at 3000 rpm: 30-32 degrees After ATDC (mark to the right of TDC)
Then at idle: it should fall around 5-7.5 degrees BTDC (mark to the left of TDC) |
Fixed ^^^^
Also read this
http://www.vw-resource.com/009_dizzy.html _________________ "Depression is a malfunction of the instrument we use to determine reality.”
Mike Gerson
What is your "Bespoke Reality"? |
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kingkarmann Samba Member
Joined: November 05, 2003 Posts: 4105
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Posted: Mon Apr 14, 2014 1:21 pm Post subject: you |
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I should clarify something;
You are looking for about 30 - 32 degrees of FULL advance. So........
Your Advance at 3000-3200 rpm may max out at about 23-25 degrees total ATDC advance once you subtract the 5-7 degrees of BTDC at idle. Hope this makes sense. _________________ "Depression is a malfunction of the instrument we use to determine reality.”
Mike Gerson
What is your "Bespoke Reality"? |
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Lionhart94010 Samba Member
Joined: January 04, 2005 Posts: 1417 Location: SF Bay Area / Silicon Valley / So Cal
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Posted: Mon Apr 14, 2014 1:28 pm Post subject: |
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Quote: |
RE: "First, at 3000 rpm: 30-32 degrees After ATDC (mark to the right of TDC)" |
??? Timing at 3000rpm should be 30-32 BTDC _________________ Current VWs 71 T2 Westy SO-72/6(Miami), 71 Crew Cab, 2015 GSW TDI
Other owned VW’s 59, 68 1500s, 69 & 71 Bug’s; 72 & 73 S-Bug’s; 67 Westy, 67 Deluxe, Other 71 DC, 72 KG GT that now lives in Australia, 12 JSW TDI, 2015 GSW TDI, 2023 Tiguan
VW technical information sights
thesamba - www.ratwell.com - www.shoptalkforums.com/ - www.vw-resource.com - http://www.type2.com/
http://bobhooversblog.blogspot.com/ - www.aircooled.net/gnrlsite/resource/articles.htm |
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Altema Samba Member
Joined: June 20, 2010 Posts: 2903 Location: Lower Michigan
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Posted: Mon Apr 14, 2014 1:31 pm Post subject: |
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kingkarmann wrote: |
Jawon wrote: |
kingkarmann wrote: |
Also, your pertronix 009 distributor is timed to 30-32 degrees of advance after top dead center AFTC (which by the way, is about full advance for the 009) at 3000 rpm. This can really only be accurately done with a timing light. The advance at idle should fall somewhere around 5-7.5 degrees before top dead center or BTDC. |
Slap to forehead! The bit of info I was missing is that 009 is timed differently and I do see lots of posts about that. But I see some inconsistencies in ATDC vs BTDC... so let me just clarify...
Is this correct?
First, at 3000 rpm: 30-32 degrees After ATDC (mark to the right of TDC)
Then at idle: it should fall around 5-7.5 degrees BTDC (mark to the left of TDC) |
Fixed ^^^^
Also read this
http://www.vw-resource.com/009_dizzy.html |
After top dead center is retard... the spark is igniting after the piston has already started on the downstroke. Before top dead center is advance. The correct timing at 3000 rpm will be 30 to 32 degrees before top dead center. At idle, the mechanical advance will go away, leaving him with anywhere from 5 to 7.5 degrees of ignition advance. |
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kingkarmann Samba Member
Joined: November 05, 2003 Posts: 4105
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Posted: Mon Apr 14, 2014 1:54 pm Post subject: |
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Altema wrote: |
kingkarmann wrote: |
Jawon wrote: |
kingkarmann wrote: |
Also, your pertronix 009 distributor is timed to 30-32 degrees of advance after top dead center AFTC (which by the way, is about full advance for the 009) at 3000 rpm. This can really only be accurately done with a timing light. The advance at idle should fall somewhere around 5-7.5 degrees before top dead center or BTDC. |
Slap to forehead! The bit of info I was missing is that 009 is timed differently and I do see lots of posts about that. But I see some inconsistencies in ATDC vs BTDC... so let me just clarify...
Is this correct?
First, at 3000 rpm: 30-32 degrees After ATDC (mark to the right of TDC)
Then at idle: it should fall around 5-7.5 degrees BTDC (mark to the left of TDC) |
Fixed ^^^^
Also read this
http://www.vw-resource.com/009_dizzy.html |
After top dead center is retard... the spark is igniting after the piston has already started on the downstroke. Before top dead center is advance. The correct timing at 3000 rpm will be 30 to 32 degrees before top dead center. At idle, the mechanical advance will go away, leaving him with anywhere from 5 to 7.5 degrees of ignition advance. |
There ya go _________________ "Depression is a malfunction of the instrument we use to determine reality.”
Mike Gerson
What is your "Bespoke Reality"? |
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kingkarmann Samba Member
Joined: November 05, 2003 Posts: 4105
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Posted: Mon Apr 14, 2014 2:03 pm Post subject: |
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Lionhart94010 wrote: |
Quote: |
RE: "First, at 3000 rpm: 30-32 degrees After ATDC (mark to the right of TDC)" |
??? Timing at 3000rpm should be 30-32 BTDC |
Left / Right
up / down
Before / After?
I'm better with pics
For Clarity:
Sorry for the mix-up _________________ "Depression is a malfunction of the instrument we use to determine reality.”
Mike Gerson
What is your "Bespoke Reality"? |
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Lionhart94010 Samba Member
Joined: January 04, 2005 Posts: 1417 Location: SF Bay Area / Silicon Valley / So Cal
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Posted: Mon Apr 14, 2014 2:10 pm Post subject: |
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kingkarmann wrote: |
Lionhart94010 wrote: |
Quote: |
RE: "First, at 3000 rpm: 30-32 degrees After ATDC (mark to the right of TDC)" |
??? Timing at 3000rpm should be 30-32 BTDC |
Left / Right
up / down
Before / After?
I'm better with pics
For Clarity:
Sorry for the mix-up |
Like your picture above :0) _________________ Current VWs 71 T2 Westy SO-72/6(Miami), 71 Crew Cab, 2015 GSW TDI
Other owned VW’s 59, 68 1500s, 69 & 71 Bug’s; 72 & 73 S-Bug’s; 67 Westy, 67 Deluxe, Other 71 DC, 72 KG GT that now lives in Australia, 12 JSW TDI, 2015 GSW TDI, 2023 Tiguan
VW technical information sights
thesamba - www.ratwell.com - www.shoptalkforums.com/ - www.vw-resource.com - http://www.type2.com/
http://bobhooversblog.blogspot.com/ - www.aircooled.net/gnrlsite/resource/articles.htm |
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J1 Samba Member
Joined: February 10, 2014 Posts: 698 Location: SoCal
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Posted: Mon Apr 14, 2014 3:35 pm Post subject: |
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Thx all. I think I got it.
So in that picture, my stock dizzy would be timed using the 5 degree ATDC notch, at idle.
BUT since I have a 009, I should disregard the notch and set a mark near the 32 degree BTDC and try to get it to the crankcase split while at 3000 rpm. And then at idle, the 7.5 BTDC mark should end up near the crankcase split.
Thx! If no further post, consider my high idle issue solved. Though I'm usually not that lucky. _________________ 1971 Ghia coupe. Assume I know nothing and you'll be pretty darn close to the truth. |
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c21darrel Samba Member
Joined: January 22, 2009 Posts: 8206 Location: San Dimas
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J1 Samba Member
Joined: February 10, 2014 Posts: 698 Location: SoCal
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Posted: Tue Apr 15, 2014 12:52 pm Post subject: |
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After adjusting the timing of my 009 (30-32 degrees BTDC @ full throttle) and then adjusting the carb (2.5 turns out, etc), my idle is still at about 1100. It's def running much smoother and quieter tho.
Some things that may be worth noting...
- Volume control screw seems to do nothing to idle speed, even screwed all the way in or very far out.
- Bypass screw is all the way in... the new o-ring is pretty tight so could that be an issue?
- Pulley is at 15-20 degrees BTDC @ idle, but I'm assuming when idle goes down to the target 850, pulley will also go down to the desired 5-10 degrees BTDC.
I believe I've done all the prereq adjustments as listed in my original post or did I miss something?
Other common culprits I should look at? Time to just send in the carb for a rebuild? _________________ 1971 Ghia coupe. Assume I know nothing and you'll be pretty darn close to the truth. |
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Woreign Samba Member
Joined: June 04, 2006 Posts: 2841 Location: Crestview FL
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Posted: Tue Apr 15, 2014 1:27 pm Post subject: |
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Some more reading that may apply in your situation:
http://www.aircooledtech.com/34pict3_modification/
Take off the air filter and look down the top of the carb and see if there is a large hole in the butterfly valve... |
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Harleyelf Samba Member
Joined: April 23, 2009 Posts: 1572 Location: Appleton, WI
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Posted: Wed Apr 16, 2014 6:55 am Post subject: |
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Check to see that your shredded fast idle o-ring didn't leave a chunk behind.
Check for air leaks.
Check slow jet for obstructions. |
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