crankshaft sprocket

[gokhane]

Hi,
I have a 1994 model Golf3. It carburettor. My engine keeps on stalling after running 3-5 km. Put in new fuel pump , cambelt. Done the cylinder head and gasket and still keeps on loosing power after driving and stalls. Finally a mechanic suggested I need new crankshaft sprocket as it would have worn out. Any suggestions appreciated.. thanks

G

[VAG Fan]

A worn crankshaft sprocket wouldn't cause a running engine to keep on dying after a few km.

You need to pinpoint the problem, either to a loss of spark, or to a fuelling problem.

Does it re-start after stalling? How soon?

[missioner]

Carb base gasket is the VERY first thing to check.

Sometimes it is the very overlooked cause of endless and varied issues.

Those new to older VW's don't think to check it, their experiences point them to radical solutions to an often simple problem.

Grab the top of the air cleaner with the engine running, rock it back and forth slowly with some force. Does the revs pick up or does the engine stall? Yes to either means that you have an air leak through the rubber carb base.

Another test, more geared to determine the condition of the carb, is to spray brake cleaner or quick start at the carb top and at the accelerator linkage. If the revs pick up its sucking air through the carb. Do this with the air cleaner fitted.

As an aside, Golf 3's have a trick to set the ignition timing. 2 pins in the OBD plug need to be shorted for the ignition box to be put into static timing mode, so that a strobe light can work properly and the base timing can be set. If your car has not been set properly it may give similar symptoms to an air leak. It will also have rubbish fuel consumption.

[gokhane]

They checked the carburettor , I was watching when they did that. Also they checked the timing and adjusted it various times. Spark plugs and distributor was also checked. All resulted same. Goes well at first and then stalls again. Now another mechanic said if cambelt slips then the timing would go out and engine would loose compression. The reason they did the cylinder head was it was loosing compression. Now would this not point it back to the crankshaft sprocket as if this has worn then belt could be slipping can causing all this ?. Thanks for responses..

G

[gokhane]

I will double check this carb base gasket to make sure..

[Donavan]

If it is really the crank pulley it might be that the key way has sheared off, this causing the pulley to turn

[VAG Fan]

"Goes well at first and then stalls again" - this has nothing to do with your timing belt.

If the timing belt does slip and as a result the engines dies, believe me, it will not miraculously re-adjust itself and start again the next morning.

[gokhane]

Hi Mark,
It does not start. That's correct. So the next person checks and readjust all that again. I was unfortunate as each time this happened I had to tow it and someone else had a look at it. Finally I gave up and towed it to my place. That's when the head was done and I m back to same.
G

[Donavan]

If it is really the crank pulley it might be that the key way has sheared off, this causing the pulley to turn

I would start here then

[gokhane]

I mean the head was done after it was towed to my place. Same mechanic who said about the compression issue and they took the head redone it and brought back. Drove for 3 km and stalled again..

[gokhane]

My car was finally fixed. As expected the culprit was the crankshaft sprocket. Connection side of it to the crankshaft was worn. So it was not catching it when turning and slipping that's why engine timing was going out. To my surprise there is only a single teeth or hump to hold on the crankshaft on that end. I wonder why they made it like that on such an important connection point. Weird stuff.

[missioner]

Still dont understand how that sprocket came loose in the first place.

The bolt that holds the sprocket on is so tight that the last time I loosened one I lay the block down on its side, wedged a railway spike (2m long high tensile steel bar) through the cylinder and the crank (the engine was mostly stripped), then put a 1.5m pipe on the end of my breaker bar and still swore like a trooper to get the bolt loose. I thought at one point my bar was going to break from the pressure being applied to it.

I had tried before with my impact gun, it sent the gun away with its tail between its legs. Total humiliation.

O.P. what I'm saying is make sure the bolt is FT. If it's not the same thing will happen again and again.

[n.gov3]

Still dont understand how that sprocket came loose in the first place.

The bolt that holds the sprocket on is so tight that the last time I loosened one I lay the block down on its side, wedged a railway spike (2m long high tensile steel bar) through the cylinder and the crank (the engine was mostly stripped), then put a 1.5m pipe on the end of my breaker bar and still swore like a trooper to get the bolt loose. I thought at one point my bar was going to break from the pressure being applied to it.

I had tried before with my impact gun, it sent the gun away with its tail between its legs. Total humiliation.

O.P. what I'm saying is make sure the bolt is FT. If it's not the same thing will happen again and again.

Was probably opened at some point and never torqued properly..... is the bolt not torqued to around 200nm

[gokhane]

If it is really the crank pulley it might be that the key way has sheared off, this causing the pulley to turn

this was the reason for all my problems.. the key was worn (sheared off) on that sprocket. I m guessing it was tricky to know that was it as I took to the car to 3 different places , no one knew what was causing it.

[M@rk]

Still dont understand how that sprocket came loose in the first place.

The bolt that holds the sprocket on is so tight that the last time I loosened one I lay the block down on its side, wedged a railway spike (2m long high tensile steel bar) through the cylinder and the crank (the engine was mostly stripped), then put a 1.5m pipe on the end of my breaker bar and still swore like a trooper to get the bolt loose. I thought at one point my bar was going to break from the pressure being applied to it.

I had tried before with my impact gun, it sent the gun away with its tail between its legs. Total humiliation.

O.P. what I'm saying is make sure the bolt is FT. If it's not the same thing will happen again and again.

Was probably opened at some point and never torqued properly..... is the bolt not torqued to around 200nm

180 nm iirc