914 1.7 Knocking Sound -- New Here, First Post, Horrible knocking coming from the motor Options

[Gint]

Can anyone explain why the idle on the driver's side carb increased with carb cleaner sprayed in and the passenger side carb bogged down when cleaner was sprayed? I could probably assume the carbs are not synched up properly.

More likely that the driver's side carb or carb to manifold has a leak. When you squirt carb cleaner in/on the carb it temporarily seals the leak and the engine runs differently for that brief moment.

I'd get a couple of kits and rebuild the carbs before going any further. It's cheap and easy enough to do. Then I'd drive it for a while. Don't thrash it, but get it driving off the idle circuit and see if you can clear out that #1 cylinder a bit.

(IMG:style_emoticons/default/welcome.png)

[VaccaRabite]

One more thing. the really black spots could be carb cleaner that dripped off the motor and got blown around by the fan. It will clean the grime it comes in contact with, and would probably be totally black by the time it dripped off.

It will evap faster then oil (lots faster) leaving a black stain, so thats a good indicator.

Zach

[UberElectricEagle]

One more thing. the really black spots could be carb cleaner that dripped off the motor and got blown around by the fan. It will clean the grime it comes in contact with, and would probably be totally black by the time it dripped off.

It will evap faster then oil (lots faster) leaving a black stain, so thats a good indicator.

Zach

I only sprayed carb cleaner down inside the carb.

[Spoke]

More likely that the driver's side carb or carb to manifold has a leak. When you squirt carb cleaner in/on the carb it temporarily seals the leak and the engine runs differently for that brief moment.

I was thinking of this too. Spray the carb cleaner on the outside of the carbs by all the gaskets: the ones from the carb to runner and from the runner to head. There should be no change in engine tune when you do this. If there is, then you have a vacuum leak and must fix it.

[Geezer914]

If one carb is feeding 2 cylinders, how can one cylinder be getting gas and the other not??? If the jets were cloged, both cylinders would not be firing.

[VaccaRabite]

If one carb is feeding 2 cylinders, how can one cylinder be getting gas and the other not??? If the jets were cloged, both cylinders would not be firing.

My thought is that if 1 is getting nothing at idle, and 2 is getting little it could still be a clogged jet. Especially if #1 is sucking less air then #2. #2 might be getting just enough to fire off idle, while 3&4 are doing most if not all of the work.

Course, I could just be retarded, and totally wrong. It has been known to happen lots of times before.

*shrug*

Zach

[Rod]

Or as two posts above it's a manifold or gasket issue. If there is a leak here it would make a hell of a racket and the cylinder would not be getting a fresh supply..

Done the second compression test yet (IMG:style_emoticons/default/popcorn[1].gif)

[UberElectricEagle]

Or as two posts above it's a manifold or gasket issue. If there is a leak here it would make a hell of a racket and the cylinder would not be getting a fresh supply..

Done the second compression test yet (IMG:style_emoticons/default/popcorn[1].gif)

Yes. I rechecked it the best I could and it #1 was still 130 to 140 ish. I have to go buy a better test gauge if I'm going to check all the cylinders. The plug was already oily black though. Not fouled up yet, just the color of the night.

Is it possible that the combustion chamber air could force out under compression where the cylinder meets the head?

[Rod]

Yes but it would be making a very different noise. This now has me stumped, you have compression, fuel and spark.. I have a feeling that fuel isn't getting through though..

[UberElectricEagle]

If one carb is feeding 2 cylinders, how can one cylinder be getting gas and the other not??? If the jets were cloged, both cylinders would not be firing.

My thought is that if 1 is getting nothing at idle, and 2 is getting little it could still be a clogged jet. Especially if #1 is sucking less air then #2. #2 might be getting just enough to fire off idle, while 3&4 are doing most if not all of the work.

Course, I could just be retarded, and totally wrong. It has been known to happen lots of times before.

*shrug*

Zach

I think it's getting enough fuel. I was just posing the question of if it might be lean because of the difference in reaction between the two carbs when I spray carb cleaner down them. Usually the normal reaction for me in the past has been they should bog down a bit with cleaner sprayed in them(I think).
Probably makes sense that there is some type of vacuum leak.

But, I think (I could be wrong) I could fix my carbs all day and I'd still have the same problem and noise. I think I will still see if the needle is needing cleaning and check if the two carbs are adjusted somewhat closely together. I believe the linkage is proper.

[Rod]

If the side with the problem is running lean, then the good cylinder will be pulling all the fuel its' way, leaving the choked cylinder dry? then when you sprayed cleaner in it all of a sudden had fuel and sparked up for a bit?

[UberElectricEagle]

Yes but it would be making a very different noise. This now has me stumped, you have compression, fuel and spark.. I have a feeling that fuel isn't getting through though..

This is my feeling, just a feeling because I am far from knowing the ins and outs of cars. I know just enough to screw myself over.

I think there is so much oil in the combustion chamber that it's not able to do a proper fuel and air mixture and it will not fire properly. #1 is the only plug that has come out black. And it was black right after I put a new one in and ran it for 5 minutes. And not a burnt black , but just a soaked in oil looking black. If that makes sense.

I would think too that spraying the carb cleaner down in there is also loosening up some of the old crud in that #1 and making a black half oil have carb cleaner like substance. It has to be really ugly looking in #1 if it hasn't been firing properly for some time.

[UberElectricEagle]

If the side with the problem is running lean, then the good cylinder will be pulling all the fuel its' way, leaving the choked cylinder dry? then when you sprayed cleaner in it all of a sudden had fuel and sparked up for a bit?

I'm not real comfortable with carbs, but I think I will see where the adjustments are in relation to the two carbs. I guess I could turn the screws all the way in and count the turns and make a note on each one.

How many screws are there to adjust on one of these carbs?

[Rod]

Yes but it would be making a very different noise. This now has me stumped, you have compression, fuel and spark.. I have a feeling that fuel isn't getting through though..

This is my feeling, just a feeling because I am far from knowing the ins and outs of cars. I know just enough to screw myself over.

I think there is so much oil in the combustion chamber that it's not able to do a proper fuel and air mixture and it will not fire properly. #1 is the only plug that has come out black. And it was black right after I put a new one in and ran it for 5 minutes. And not a burnt black , but just a soaked in oil looking black. If that makes sense.

I would think too that spraying the carb cleaner down in there is also loosening up some of the old crud in that #1 and making a black half oil have carb cleaner like substance. It has to be really ugly looking in #1 if it hasn't been firing properly for some time.

Exactly my thoughts too.. The reason that piston may be making compression is that it is sooo full of crud that it's reducing the swirl area. It needs to be cleaned out - which running at tickover is not going to do, it needs to be revved under load to clean te sucker out, but is it getting fuel in the first place.

With regards to the adjustment on your specific carb - sorry, but I have 0 idea. (IMG:style_emoticons/default/sad.gif)

[Spoke]

Try the carb cleaner spray on the outside of all the seals. It's very easy to do and could yield big results. You should have no change in engine tune if the gaskets are ok.

[UberElectricEagle]

Try the carb cleaner spray on the outside of all the seals. It's very easy to do and could yield big results. You should have no change in engine tune if the gaskets are ok.

I will try this first and then move onto trying to adjust the carb and clean the main jet or if that's what it's called.

I think Zach pointed me to the correct screw for the main jet.

[stugray]

Just a WAY shot in the dark..... have you checked the oil level?
Is it way too high?

Also instead of carb cleaner, you could repeat the squirt test with some starting fluid.

If that side is starved, it will rev higher.

Stu

[Jax914]

You pulled the rocker covers, but did you check the valve lash? There can be a very big impact when the lash isn't correct. The engine must be stone cold - do not run it the day you plan to adjust.

Lots of links out there to how this is done. You only need basic tools and some time.

http://www.vwtrendsweb.com/tech/0106vwt_va...ment/index.html

http://www.aircooledvwlove.com/how-to-adju...oled-vw-engine/

http://www.vw-resource.com/valve_adjust.html

A leaking intake manifold gasket will normally result in a lean condition - spraying starting fluid around the base of the carb and manifold to head should quickly reveal any leaks.

Your plugs are showing extreme oil deposits / carbon fouling.

http://www.aa1car.com/library/reading_spark_plugs.jpg

An improperly gapped plug / bad plug wire / fouled cap or rotor can make the plug not fire. Be aware that under compression, your plug may not fire, even though it fires when you pull it and look at it.

It's cheap to adjust your valves, put new a cap, rotor, points (or get a Petronix) and wires.

Lastly, pull the main coil wire, and after you've adjusted the rockers to the proper lash, leave the cover off and have someone crank over the motor - watch and make sure the rocker arms are actually moving - it may be a rounded off lob on the camshaft. It's easy to check and see with the cover off.

When you're at higher rpm's, it's easy to mask one cylinder not working properly.

HTH,

[UberElectricEagle]

You pulled the rocker covers, but did you check the valve lash? There can be a very big impact when the lash isn't correct. The engine must be stone cold - do not run it the day you plan to adjust.

Lots of links out there to how this is done. You only need basic tools and some time.

http://www.vwtrendsweb.com/tech/0106vwt_va...ment/index.html

http://www.aircooledvwlove.com/how-to-adju...oled-vw-engine/

http://www.vw-resource.com/valve_adjust.html

A leaking intake manifold gasket will normally result in a lean condition - spraying starting fluid around the base of the carb and manifold to head should quickly reveal any leaks.

Your plugs are showing extreme oil deposits / carbon fouling.

http://www.aa1car.com/library/reading_spark_plugs.jpg

An improperly gapped plug / bad plug wire / fouled cap or rotor can make the plug not fire. Be aware that under compression, your plug may not fire, even though it fires when you pull it and look at it.

It's cheap to adjust your valves, put new a cap, rotor, points (or get a Petronix) and wires.

Lastly, pull the main coil wire, and after you've adjusted the rockers to the proper lash, leave the cover off and have someone crank over the motor - watch and make sure the rocker arms are actually moving - it may be a rounded off lob on the camshaft. It's easy to check and see with the cover off.

When you're at higher rpm's, it's easy to mask one cylinder not working properly.

HTH,

I checked the valves and adjusted the ones that needed it. It's toward the beginning of this maze of posts.

I watched the rocker arms move while I rotated the tire. They all seemed to be working properly.

My plugs are new and at the proper gap.

I'm going to head out and work on the fuel delivery.

[UberElectricEagle]

Just a WAY shot in the dark..... have you checked the oil level?
Is it way too high?

Also instead of carb cleaner, you could repeat the squirt test with some starting fluid.

If that side is starved, it will rev higher.

Stu

Yes, I checked the oil and added some. IT leaks plenty to never be too full.