TheSamba.com :: View topic - Car sputters and still left it fully warm up

Fri Dec 17, 2010 4:40 pm

I have 72 completely stock other than gt style exhaust. Its 1600 Dual Port, I have done is oil and transmission oil change, spark plugs and checked valve clearance. I have left my car fully warm up, 5 min just running. Just on idle doing a few revs, the motor does rev fine at times. But theirs moments when pedal is applied that it sounds its about to stall, either it catches itself continuing with the rev or it dies. I took it out for a drive, when theirs moments when other people are just punks that are right on my tail I try to accelerate :( it stumbles pretty bad and I begin slowing down. I dont know what else to check, im glad got car running fine no hassle of a start up and all electrical working great. Just this issue throwing me off

Fri Dec 17, 2010 4:55 pm

medic4.life wrote: I have 72 completely stock other than gt style exhaust. Its 1600 Dual Port, I have done is oil and transmission oil change, spark plugs and checked valve clearance. I have left my car fully warm up, 5 min just running. Just on idle doing a few revs, the motor does rev fine at times. But theirs moments when pedal is applied that it sounds its about to stall, either it catches itself continuing with the rev or it dies. I took it out for a drive, when theirs moments when other people are just punks that are right on my tail I try to accelerate :( it stumbles pretty bad and I begin slowing down. I dont know what else to check, im glad got car running fine no hassle of a start up and all electrical working great. Just this issue throwing me off

Sounds like you either have a vacuum leak or your air/fuel mixture is not adjusted correctly. BTW, idling for 5 minutes does not warm up the engine. It does warm the choke so it is open, but the engine is still not at operating temperature.

Fri Dec 17, 2010 4:58 pm

vacuum leak will cause sputtering on acceleration, check the rubber boots on the intake manifold, they are common sources of a leak.

Fri Dec 17, 2010 5:33 pm

Which carb do you have. If you have a original 34 PICT it has a bad flat spot in it that is very hard to get out. You can make it drivable but it will be al ittle flat at one throttle range. You will have to be very patient as you adjust this. You do need t make sure there are no vacuum leaks before you putter with the carb

Fri Dec 17, 2010 5:41 pm

flyboat wrote: Which carb do you have. If you have a original 34 PICT it has a bad flat spot in it that is very hard to get out. You can make it drivable but it will be al ittle flat at one throttle range. You will have to be very patient as you adjust this. You do need t make sure there are no vacuum leaks before you putter with the carb

Please explain about the flat spot in the 34 PICT 3. I haven't hear that one before.

Fri Dec 17, 2010 6:02 pm

Usually the flat spot occurs shifting from first to second, getting back on the throttle creates a hesitation. If you drive the car hard its not as bad. Easing along the car may stammer abit. That's my experience

Fri Dec 17, 2010 6:11 pm

tailwaggers wrote: flyboat wrote: Which carb do you have. If you have a original 34 PICT it has a bad flat spot in it that is very hard to get out. You can make it drivable but it will be al ittle flat at one throttle range. You will have to be very patient as you adjust this. You do need t make sure there are no vacuum leaks before you putter with the carb

Please explain about the flat spot in the 34 PICT 3. I haven't hear that one before.

34 pict 3 carbs do not have a flat spot. However, using them with an incompatible distributor, like an 009 does create a flat spot. However, if your engine is stock, and that means you have a vacuum advanced distributor, then your problem is going to be either a vacuum leak or the air mixture is not adjusted correctly. You are most likely running too lean.

This link should help figure it out: http://www.vw-resource.com/34pict3.html

Fri Dec 17, 2010 6:38 pm

Thanks, I will hold this in reserve. I have had cars with this carb since 1977. This info would have been good to have

Sat Dec 18, 2010 3:04 am

alright, ill be checking for leaks tom morning. Then be checking into the carburetor as far as I know its stock carb

Sun Dec 19, 2010 1:18 am

It's the cheap knock off 009 distributors and the 34 carbs that create a flat spot. If you have a good quality 009 and everything is in spec you won't have a problem. I know this because I run a 009 and 34 carb on mine. Also the factory owners manual discourages letting the car sit to warm up.

Find out where the carb was made and what distributor you have. Once we know that we can provide tuning tips.

Sun Dec 19, 2010 1:40 am

How would I figure what type of dizzy I have

Sun Dec 19, 2010 1:54 am

If there is a big ufo looking thing on the side with a vacuum line going to it, probably a svda. There will be a part number on the side of it, let us know what it is and we can tell you what you have. Where it was made should be on it somewhere as well.

Tue Dec 21, 2010 11:57 am

I couldnt find the ufo symbol so i took a pic

I been checking the repair manual thats in the technical section, it does not show how to adjust the fuel, only thing it show is adjusting the idle. If I need to add fuel where is located?

I also found this
and on the manual it dont show where does it connect to. I apoligise for crappy engine bay, im working on it and fixing all PO mistakes.

Tue Dec 21, 2010 12:16 pm

Your distributor is an 009 mechanical advance and your carb is a 34 pict 3 (or possibly 34 pict 4). The 009 is not stock and will not function well with that carb (which is stock).

You have two choices: 1) replace either the distributor or carb or 2) modify the carb to make it function better with the 009. There are lots of threads on how to do this, search on 009 34 pict 3 or something like that.

If you choose option 2, know that it can be made to run better, but won't ever run well. Also, the combination of the 009/34pict3 does not rule out vacuum leaks or maladjusted carburetor.

Wed Dec 22, 2010 2:08 am

I found in the junkyard a dizzy with a single diaphragm vacuum advance. Would it be a good move to pull and have the mechanical dizzy replaced?

Wed Dec 22, 2010 8:35 am

The short answer is "It depends." If you have a vacuum leak or the air mixture is adjusted incorrectly, just changing the distributor won't fix the problem.

Also, with the new distributor, it is important to check it out and make sure the vacuum advance actually works. You can do this by connecting a hose to the can and suck on it while looking into the distributor. If the the plate moves and doesn't fall back until after you release the pressure you sucked with, it is working. If it doesn't move, or falls back unless you keep sucking on it, then the diaphragm is probably shot and a new vacuum can can be expensive. Also, you want a distributor that is both a mechanical advance and a vacuum advance. VW had some early models that were vacuum only. They work, but not as well.

I think it still sounds like your carb mixture isn't adjusted correctly or you have a vacuum leak. Could also be your accelerator pump has a bad diaphragm and isn't squirting fuel down the carb when you accelerate.

Before swapping distributors, I would try and get the carb tuned in correctly. The procedure is found at http://www.vw-resource.com/34pict3.html . If you are hesitant to do this yourself, you can take it to a vw shop and have it done. Shouldn't cost more than a 1/2hour worth of labor (only takes about five minutes).

Even with an 009, if the carb is set up correctly, you will have a flat spot at initial acceleration from a stop (before the mechanical advance kicks in), but not the other problems you are having.

Wed Dec 22, 2010 8:46 am

Do you have heat risers that are actually working correctly?

Get a better distributor and don't mess with the carb.

Wed Dec 22, 2010 9:04 am

Randy in Maine wrote: Do you have heat risers that are actually working correctly?

Get a better distributor and don't mess with the carb.

Even with an 009, he shouldn't have the problem with accelerating once at speed. Sounds like the fuel mixture is off more than a carb problem.

Wed Dec 22, 2010 10:28 am

Ok I have checked for leaks already by spraying brake cleaner. So far no leaks. Is this the accelarator pump?

I have checked the repair manual it does not show how to run vacuum lines to the item pictured. Im working with carb right now

Wed Dec 22, 2010 10:48 am

medic4.life wrote: Ok I have checked for leaks already by spraying brake cleaner. So far no leaks. Is this the accelarator pump?

I have checked the repair manual it does not show how to run vacuum lines to the item pictured. Im working with carb right now

No, that isn't the accelerator pump. It's built into the right side of the carb when you are facing in the engine (the side of the carb with the generator). A quick way to see if it is working is to take the air filter off and then pull back on the the throttle arm (engine should be off when you are doing this). You should see a strong squirt of gas go down the carb. If you do, then the accelerator pump is probably alright.

I'm betting, though that your air mixture is not adjusted correctly. It is the small screw on the right side of the carb. However, you should not just turn it willy-nilly, but follow the adjustment procedures in the link I posted earlier.

Once you get your carb set correctly, then you can decide what to do about your distributor or not. Many people run an 009 and experience little hesitation, others have a lot of hesitation. If your's is acceptable for you, then don't change it. Although a distributor with a vacuum advance on it will normally get you better mileage over an 009. But your main priority right now should be getting the car running correctly.