[T3] Mysterious squareback condition.... need suggestions.

[James Lingenfelter]

  These Weber carbs have no electric chokes. Is the balance pipe the  
vacuum line between the two intake manifolds? If so, it is ok because  
I had the carbs off the other day and checked those connections.

On Jan 26, 2011, at 5:42 AM, Dave Hall wrote:

> Check both carbs have the choke heater wires connected firmly -  
> they can
> fray with engine vibrations over time - and operate correctly.  If  
> one is
> fully closed and the other opening properly, you will get very uneven
> running.  (Assumes you still have the autochokes functioning, not  
> disabled
> and set permanently open).
>
> Another twin carb problem is if one of the balance pipe connections  
> is loose
> and causing an air leak.  That will cause a similar fault.
>
>
> Dave.
> UK VW Type 3&4 Club
> ===================
>
> -----Original Message-----
> From: type3-vwtype3.org-bounces at lists.vwtype3.org
> [mailto:type3-vwtype3.org-bounces at lists.vwtype3.org] On Behalf Of  
> James
> Lingenfelter
> Sent: 26 January 2011 00:42
> To: type3 at vwtype3.org
> Subject: [T3] Mysterious squareback condition.... need suggestions.
>
>    I have a '68 squareback, with dual Weber 34ICT carbs. My wife  
> drives it
> much more than I do. About 6 weeks ago she called me saying it had  
> started
> running poorly on her way home from the store, felt like it was  
> missing,
> started backfiring, etc. She got a block from home and it died and  
> would not
> restart. When I got home I looked at it and saw nothing other than  
> the coil
> wire being slightly loose.
> After pushing that back on, it started immediately, idled  
> perfectly, I took
> it for about a 45 minute test run and it ran absolutely perfectly. I
> determined either the coil wire had been coming off, or either my  
> wife was
> going nuts.
>    We continued driving it over the last month with no problems  
> whatsoever.
> Then yesterday, my wife was taking it to the grocery store..... she  
> said it
> was hard to start, then ran horrible leaving home, so she  
> immediately came
> back and parked it. She tried later in the day to start it and  
> couldn't.
> When I got home from work, I got it started after much cranking and  
> pumping
> on the gas, but then it idled horribly and would die within 30  
> seconds if
> you let off the throttle.
> And I witnessed it backfire once through the passenger side carb  
> when I
> opened the throttle from the engine compartment. From randomly  
> inspecting
> things in the engine compartment I discovered massive corrosion at  
> the plug
> wire connections to the distributor cap..... I was already planning to
> replace them since one plug wire had shocked me through the shielding
> recently. I consulted with my brother, who's an auto mechanic, and
> determined that, considering the all-day rain we had yesterday, that I
> indeed had an ignition problem probably resulting from poor  
> connections or
> arcing somewhere.
>    So, today I replaced the distributor cap, rotor, and plug  
> wires.... It
> started immediately, idled OK; I let it idle in the driveway about 15
> minutes, then took it for a shakedown run. I drove about 5 minutes,  
> and
> suddenly without warning, it felt like it was running on two  
> cylinders.....
> not even three, but TWO. Barely enough torque to let in the clutch  
> in any
> gear without killing the engine. I let off the gas and it idled  
> very slowly
> and lopsided, and was destined to die.... I revved it, it sounded  
> ok again,
> and I pulled over the first decent place I came to. I shut it off  
> for a few
> minutes. It restarted easily, and ran fine coming back home.
>    So this is where I'm at now. I've now witnessed what my wife has  
> been
> trying to describe, and I have no idea what it is. Fuel pump is good,
> recently replaced fuel filters; intake leaks that plagued me  
> forever are
> permanently fixed.... I maintain this car pretty obsessively since  
> it's a
> daily driver. Could it be a carb issue?
> Sorry this message is so long, but I thought I'd relay every detail  
> in case
> any of it helps. Any clues or suggestions will be greatly appreciated!
>    Thanks,
>     Jimmy
>
> _______________________________________________
> VWType3.Org mailing list - type3 at vwtype3.org
> http://lists.vwtype3.org/listinfo.cgi/type3-vwtype3.org
> Contact gregm at vwtype3.org if you need help with the list.
>
> _______________________________________________
> VWType3.Org mailing list - type3 at vwtype3.org
> http://lists.vwtype3.org/listinfo.cgi/type3-vwtype3.org
> Contact gregm at vwtype3.org if you need help with the list.