Cylinder firing

I have a 1600 single carb. running rough at idle and will stall very easy when cold.. Replaced distributor cap, points, rotor, plug wires, and set the idle and timing per manual and reset all valve clearances....distributor is advancing..when I pull the wires from the plugs while the engine is running it seems #4 does not have much of an impact. It is receiving spark (removed wire off of distributor and can see the spark jump to the wire) any ideas ?? Before bring it in to get looked at would like to try a bit more myself to fix the problem.
Thanks in advance

Bruce

Could be lots of different things. You said you pulled the wire from the distributor cap and saw spark. Next thing to do is to pull the wire the wire from the plug and stick a small screw driver in the plug boot and hold it next to metal and see if the spark jumps from the screw driver to the ground. If you have spark at the wire then pull the plug and check the plug the same way, insert the plug in the boot and ground the side of the plug and look for the spark to jump the gap. Finally, change plug wires, you could still have a problem with the wires or the plug eventhough the spark. The spark could be so weak that the compression blows out the flame.

Another costly problem could be a burned valve, bad rings, bad piston or scored cylinder or a cracked head. A compression test will reveal if these problems exist.
(Message Edited 9/7/2003 10:42:42 PM)

Thanks will let the forum know how it goes...

Check valve clearance on #4; if that's OK check compression or do a leakdown test on #4. Also, make sure carb jets for that cylinder are not plugged if you have dual Weber IDF's or Dellorto DRLA's.

Do not have dual carbs just a single Solex 30/31pict. I just finished replaceing plugs checking wires and point gap , timing ( the best I could with a idle of about 1200 to keep it running) and will wait till the engine cools back down to check the valve clearances once again. Aftervall that I guess I will have to do the leak down and compession test. I don't have the equipment Is it worth it to purchase or bring it to a shop that has it...?

A good leakdown test setup can be expensive unless you make it yourself, and you also need an air compressor. Probably simpler to take it to a shop that works on air-cooled VW's and have them do it (or a compression check) if it proves to be necessary after you check the valves.

After checking the valves and if they appear o.k...If the leak down or compression test reveal a problem does the engine need a complete overhaul or what is the procedure from here..
Thanks again

Bruce, one thing at a time. If you have low compression on one cylinder it could just be a valve problem, but might include piston and rings or even camshaft/lifters. You'll just have to get some good diagnostics on the engine first.
(Message Edited 9/9/2003 12:41:12 PM)

Hey George. This may sound strange, checked the valve clearence twice thru. Checked timing again..Once again plugs are new and so are the wires even swaped them around after each adjustment..after checking the valve clearence the first time # 4 regained power but still was running rough on idle. Checked each cylinder once again but now #2 was not making a difference. Engine cool down check valves again, run it up and #2 gets the power back but #4 is not making a difference again..so kind of stuck here. Could all of this be caused by the carb. not adjusted or fouled somewhere. Sprayed it down with carb cleaner but to no avail. Sorry so winded

Bruce

Hey George. This may sound strange, checked the valve clearence twice thru. Checked timing again..Once again plugs are new and so are the wires even swaped them around after each adjustment..after checking the valve clearence the first time # 4 regained power but still was running rough on idle. Checked each cylinder once again but now #2 was not making a difference. Engine cool down check valves again, run it up and #2 gets the power back but #4 is not making a difference again..so kind of stuck here. Could all of this be caused by the carb. not adjusted or fouled somewhere. Sprayed it down with carb cleaner but to no avail. Sorry so winded

Bruce

Check for vacuum leaks?

Checked for vacuum leaks, can of carb cleaner sprayed around, found the only change to idle would be at the needle valve area.Could be a bit worn, ordered a rebuild kit for the carb and will try that when arrives. If THIS doesn't do the trick its off to the shop...
Thanks for all your help.

After searching I found the 009 dizzy should be timed at full advance 28deg to 30deg. I have done that and let the idle go where it may which works out to around 8deg reset carb and seems to have fixed my problem of cylinder firing and erratic idle. Will rebuild carb anyway when I get the kit. Got any tricks to do the rebuild teh carb or just follow basic directions?