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Tue Feb 23, 2010 3:37 pm

recently bought a 71 squareback, didnt run well but had not been run regularly for a year and a half. previous owner stated carbs as reason. bought and installed new dual carbs and increased power but still running erratic. started getting more into it and figured out the #1 and #3 were missfiring at idle and at velocity, more so at idle however. have checked timing, seems accurate. VW guy here in town i think is trying to milk me wants to replace the cam or sell me a new motor. Has good similar compression in all cylinders so i doubt its the cam? Am going to replace the plugs and wires and check the valve clearances and see what happens there. should probably have posted after i tried those things. is a 1600 motor was fi, but converted to carburetors at some point

Tue Feb 23, 2010 3:42 pm

Pull all 4 plugs and tell us what you see. My guess is that you'll pull the intake manifolds and find that either the 13mm nuts by #s 1 and 3 are loose, or the guy that put them on used the crappy metal gasket that comes in the engine gasket kit between the manifold and the head, or both.

What you're describing is a classic vacuum leak at the base of the intake manifolds.

Fri Feb 26, 2010 11:08 am

so got plugs and wires, pulled my first plug and realized the parts place had given me wrong plugs. So i changed the coil wire only and drove it to get the correct plugs but noticed a significant change replacing the coil wire only. Got correct plugs and replaced those and remaining wires, noticed all but one plug the gap was off were gapped at 28 instead of 24 have got to run more tests to see if cylinders are still missing but if they are it is nowhere near as hard a miss as it was previously. Much better acceleration and no hard lunges through the gears as before. will update further, going to see if it will now pass emissions. wouldnt before because it wouldnt pass the constant velocity missing so badly.

Fri Feb 26, 2010 2:53 pm

new plugs and wires made the difference, pretty sure it was that coil wire though.passed emissions. am going to get a new coil and electronic ignition shortly though, should help too.

Fri Feb 26, 2010 6:03 pm

passed emissions?!

Sun Mar 14, 2010 4:51 am

About 1 and 3 I 'm having the same situation, when the engine starts and I take the cable from distributor of number 1 and number 3 nothing happens. Checked for air leaking putting some carb cleaner but nothing happened. There is spark on both the cilinder.
For me it seems one of 3: or no fuel is getting in to those cilinders, (carbs), or timing i mean spark is missing the fuel wich, or smell to camshaft. Carbs are 34 weber ICt'S, timing w/ 009 @ 7.5 ; new valves int. and exh; 88mm pistons; new sparks and sparks cables; dwell 51; compression over 100; Number one TDC @ rotor is @ 10 o'clock. I'll still working on this please SOS :cry:

Sun Mar 14, 2010 9:56 am

Do you have a balance tube between the 2 intake manifolds????
Without one, ICT's will run like crap at idle.