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On 16 Nov 2005 at 12:19, fess wrote: > > On Nov 16, 2005, at 6:46 AM, Jim Adney wrote: > > > On 15 Nov 2005 at 17:32, fess wrote: > > > >> I think I had been ignoring a slight missing or sputtering problem on > >> the > >> short drives I've been doing. But now that I drive it on the freeway > >> for the > >> first time in a while, I'm feeling like it's not in very good shape. > > > >> It seems to be slightly intermittent, but perhaps relative to the > >> throttle position. > > > > What year? If it's a 72-3, suspect the throttle valve switch. > > It's a 72. [ door sticker of 11/71 ] > > You can test this by disconnecting the switch for a few days and > > seeing if the miss goes away while driving. > Hmm. Ok, I can try that. I have to figure out which switch that is. It's the black box on the right end of the throttle valve shaft. > > Otherwise, check the SP connectors for their 1000 Ohms, and the spark > > plugs > > themselves for wear (rounded electrodes.) > > Ok, I can try this too. thanks. > > Last night I drove it home and tried to pay more attention. > It seems to happen in correlation with RPM or possibly load. > I think that it happened at slightly lower RPMs when > I was going up an incline. So, less about > throttle position. The throttle valve faults tend to occur at one specific spot, where the throttle spends a lot of time while driving. Typically this is your cruising position. > I'm not sure I may know what missing / sputtering is, > so here's my laymans description of the event. > > As I accelerate I hit a point where suddenly it > seems to loose power. The noise the engine makes > seems to be a little bubbly like someone > just blew put the pipes through some water. > but it's not that loud. A miss is just the engine missing a single power stroke. You feel it as a very small jerk backwards which usually repeats at irregular intervals. > After driving home, I started to suspect advance mechanism? > since that seems related to RPM. Your description does not seem like an advance issue. > So, I pulled the distributer cap, and twisted > the rotar, it turns a little, then snaps back. > I pulled the small vacuum hose off the intake > that goes to the outside of the can on the distributer. > I sucked on that and watched the arm tighten. > I sucked pretty hard, and it moved the plate > in the distributer. Is that supposed to move easily? > could that be the issue? Sounds fine. > Last I checked the throttle position switch for the clicks. It makes 20 > clicks but clicks #3, #5, and #8 are very weird they sound like a quick > series of clicks rather than one click. [ like a drummer doing a flam. > ] [ Also at this point, the return spring popped off, and I don't know > if I got it on right. anyone got a picture? I think the hook might have > partially broken. ] It sounds odd that the clicks would not all sound pretty much the same. This sounds like it could be a throttle valve switch problem, but I've never seen one that went bad in more than one spot. Still, this is easy to check by just doing the test above. > My fear is that the timing is just off, which I don't feel confident > doing myself. However I did have it's valves adjusted and timing done a > few months ago. [ looks like he lubbed the points cam too. ] You've worked yourself thru much harder things. Maybe it's time to tackle the timing. Do you have a timing light? Keep in mind that the '72 timing adjustment is different from all the other years. Only the Bentley manual gets it right. So follow that scheme closely. -- ******************************* Jim Adney, jadney@vwtype3.org Madison, Wisconsin, USA ******************************* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ List info at http://www.vwtype3.org/list | mailto:gregm@vwtype3.org ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~