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Sat Nov 14, 2015 4:40 pm

I purchased a beautiful type 3 squareback, and am trying to improve my mechanical inclinations with its relatively simple engine. The previous owner converted it from fuel injection to dual carbs.

My question is what would cause it to stall at intersections? If I put it into neutral, it will stay running, but it should do so in gear as well. I have adjusted the idle to what I think is pretty high, but it is still not high enough to avoid stalling.

I am suspecting it has more to do with the transmission than the idle, but before I start digging into that I figure I would seek advice here.

Any thoughts?

Sat Nov 14, 2015 7:46 pm

The points/ timing are off OR it's running too lean.

Sun Nov 15, 2015 6:25 am

First find out what your idle actually is. With the car fully warmed up, it should be 950 rpm, plus or minus 50 rpm.

Sun Nov 15, 2015 8:45 am

Thanks, I will look into it. They are Weber TPIO 34 ICT's.

http://imgur.com/a/WtKRG

Sun Nov 15, 2015 9:26 am

I wanted to cross post the response and advice that I received from another site. I am going to rebuild the carbs as soon as I get the kit.

https://www.reddit.com/r/MechanicAdvice/comments/3..._stalling/

Sun Nov 15, 2015 10:24 am

grnerd wrote: Thanks, I will look into it. They are Weber TPIO 34 ICT's.

http://imgur.com/a/WtKRG

I tried 3 times to get the picture to load without success. How about posting an engine shot or 2 to the Samba gallery, so we can actually see what set up you have. This is mainly so we can see what linkage you have, and whether or not you have a balance tube, and how your vacuum tube to the modulator (on the trans) is plumbed. This is very important, as the wrong plumbing won't give you the correct signal.
Also, check where the manifold bolts to the head, as you might have a metal gasket there, and that's a no no.
Like Tram was thinking, you might have a vacuum leak (causing the lean running), but it's also possible that you've got the wrong jets in the carb (depending on the carb kit used). The CB Performance kits are about the only ones I've found that were jetted close for a 1600 engine. The chinese kits are usually rich, don't have a balance tube, and the linkage just sucks.

Sun Nov 15, 2015 5:28 pm

Ok, here is a shot of the engine. I can upload those shots of the carb itself if you want.

Sun Nov 15, 2015 10:12 pm

grnerd wrote: Ok, here is a shot of the engine. I can upload those shots of the carb itself if you want.

Thank you.
It looks like you've got an 009 distributor (known for having a "flat spot" just off idle), and no balance tube (where you'd want to pull vacuum for the trans). Note, these 2 items alone can cause tuning difficulties with an AT. Trying to get the 009 timed to work well with the AT will be your biggest challenge. Ideally you want to time the engine @ 2500 and have 28 to 30* max advance, and let the idle timing fall where it will. The lack of a balance tube (it smooths out the pulses between the left and right engine banks) hurts getting the carbs dialed in, as you don't get some of the vacuum draw from the opposite side of the engine. You'll need a carb balance tool (synchrometer) to dial them in, but to add the balance tube, you'll have to drill and tap the manifolds for hose barbs, and then add a "T" in the hose for the trans. That will give you a good signal for the trans to shift correctly (pulling from both sides of the engine). Adam had to drill and tap 2 holes on each of his manifolds just to get a better signal to the trans, on his old 70 Square that he sold last year. Some transmissions need the extra vacuum, but most don't. But, without the vacuum hose (or any vacuum supplied), the trans shifts very hard, and winds out between shifts (really stretches them out). It reallly needs a vacuum source to work correctly.

Oh, you also should get the fuel filter out of the engine compartment (fire hazard).

Mon Nov 16, 2015 5:47 pm

Thanks for the tip. I will be pulling the carbs in the next week or so. Should I look for an alternative to the 009 distributor? I will do a search for a guide to installing the balance tube.

Mon Nov 16, 2015 7:43 pm

My experience is the old automatics are not like modern ones. When idleing in gear it still wants to "push" the car. It's okay for short periods like stopping at stop sign, but at a long light you need to shift to nuetral.

It also seems happier idling around 1100.

You will also find that you still need to drive with two feet...... :wink:

Wed Nov 18, 2015 2:07 am

there's no need to shift to neutral at every light...you will probably put a lot more wear and tear to your trans by doing that

Wed Nov 18, 2015 5:01 am

Slow 1200 wrote: there's no need to shift to neutral at every light...you will probably put a lot more wear and tear to your trans by doing that

I disagree. I've done that with mine ever since I got it. I don't see how that would put any extra wear on the transmission as opposed to leaving it in Drive.

Wed Nov 18, 2015 6:58 am

It puts zero wear on it leaving it in drive.

Yes....these "earlier" automatics are different from modern ones....but not that different. Mainly in control systems and overall tuning. The design of the driveline and what makes it work are very similar.

What is causing the car to creep is the designed in lock up pressure/rpm of the torque converter. Its an overall refinement of design thing.

In these transmissions the controls are 90% hydraulic. The only non-hydraulic control parts are the vacuum modulator and the centrifugal governor.

Because of these hydraulic controls....you have to have enough fluid pressure to overcome the unseating pressure of the springs in various hydraulic parts in the valve body. That fluid pressure is rpm related....and age variable as springs age and pump wears.

Add to that...because these engines dont have much torque....relative to most cars that had automatics back in the day.....its odd that they designed a torque converter with a low stall point (not really....because they went for smoothness of takeoff rather than quickness of lockup).
What is happenjng with the creeping is that you have some partial hydraulic lockup in the converter when sitting at a light.

This is a little worse on the carbed engjnes......because of lower vacuum signature at idle....coupled with a little hydraulic control spring weakness from age.....and the low stall point of the converter.

Also....just so you are aware.....there were several valve body part #s. I believe the automatic valve body on carbed engines had different calibration than those for the fuel injection...so if that car originally had EFI...its going to shift diffetently with carbs. Ray

Wed Nov 18, 2015 7:11 am

I agree with all the above in addition i will say things have to be right in valve adjustment, timing , plugs , plug wires, vacuum leaks etc. Mine automatic would not idle correctly until i had i had done all those things in addition to using a syncro tool. i would think i had it set right until in gear and awe sh... bobnotch says use syncro tool on left carb first. i did it works.
I would bet not one one in 109 vw nuts could correctly set twin carbs without a syncro tool.

Wed Nov 18, 2015 8:15 am

raygreenwood wrote: I believe the automatic valve body on carbed engines had different calibration than those for the fuel injection...so if that car originally had EFI...its going to shift differently with carbs.

I do know there was a different modulator valve for the carbureted cars.

Wed Nov 18, 2015 8:17 am

Nice explaination Ray -

In my case I'm breaking in a new motor, and have a thoroughly gone through AT. As they loosen up and get happy, I probably won't be shifting to neutral as much.

I have to say part of it is I'm getting use to the Automatic as well and just have this fear of stalling and having the battery die..... :oops:

Carb sync made a huge difference, but I did cheat it a little and used the linkage adjustment on the left carb. I also used hose clamps on the vacuum lines. I think that made a difference too.

Wed Nov 18, 2015 8:29 am

My stock '69 FI/AT never stalls. I just use the brakes, so it doesn't creep like every other automatic transmission in Drive. Dual carburetors will be harder to get set-up with an AT. Air-Cooled Head said it only took him 20 minutes to add a balance tube to his aluminum carburetor manifolds, so you can do that while you are waiting for the carburetor kits.
http://www.thesamba.com/vw/forum/viewtopic.php?t=642018

Wed Nov 18, 2015 8:38 am

reay wrote: Nice explaination Ray -

In my case I'm breaking in a new motor, and have a thoroughly gone through AT. As they loosen up and get happy, I probably won't be shifting to neutral as much.

I have to say part of it is I'm getting use to the Automatic as well and just have this fear of stalling and having the battery die..... :oops:

Carb sync made a huge difference, but I did cheat it a little and used the linkage adjustment on the left carb. I also used hose clamps on the vacuum lines. I think that made a difference too.

Also....very few VW owners actually get down and dirty and do the age related items that were needed due to mileage.....even long before age issues.

There is probably not one AT transmission in type 2,3 and 4 that runs exactly as it should....simply because they are 40 years old...have reduced pump output and main pressure....slight or even heavy wear to valve body bores etc etc.

The first thing that should be done when you get a used type 3 or 4....at minimum...is a reseal job. All seals especially between the gear and differential section and the governor shaft seal.
Then adjust the bands.
Then pick up the brown Bentley manual and get some proper gauges and hoses, do the driving and stall test and adjust the main pressure at the modulator valve.

Then....when you have the pan off to reseal it and change the filter...look for the valve body code. Make sure the modulator valve you have matches the valve body.

Quote: I do know there was a different modulator valve for the carbureted cars.

Yes....from bits and pieces I have read...its not just the modulator...its a completely different valve body on some cars. Not saying you should go search ing just for "X" valve body....gotta work with what you can get....but be aware there are differences you may have to tune around if you want perfect. Ray

Wed Nov 18, 2015 10:12 am

I'm running a FI modulator on a carb car (original euro-spec), I did have to adjust it a tiny to get the shift points just right, it runs great now.

And yes, adjusting idle speed can be a little trickier on a carbed auto, but once you get it right it never stalls or creeps too much (it always creeps a little bit), 1100 rpm is definitely too high, that's for sure!

On the other hand, the valve bodies are matched to the governors, I have a whole FI auto trans for parts, one day I might dig into it to see what the differences are.

Wed Nov 18, 2015 12:32 pm

Slow 1200 wrote: I'm running a FI modulator on a carb car (original euro-spec), I did have to adjust it a tiny to get the shift points just right, it runs great now.

And yes, adjusting idle speed can be a little trickier on a carbed auto, but once you get it right it never stalls or creeps too much (it always creeps a little bit), 1100 rpm is definitely too high, that's for sure!

On the other hand, the valve bodies are matched to the governors, I have a whole FI auto trans for parts, one day I might dig into it to see what the differences are.

Yes....the valve bodies are matched to the governors at the factory. That is a whole different issue as well. But the valve bodies themselves have letter code series in their part numbers that are designed for specific applications as well. Ray