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ac78
Samba Member
Joined: March 18, 2008
Posts: 330
Location: Nashville
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 Posted: Thu Apr 14, 2016 4:35 pm Post subject: Re: Vacuum/Timing questions |
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Here is a post test drive vacuum test.
https://www.youtube.com/watch?v=xHMo9Wz13rE
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78 Westy 2.0l hydr. FI
VW Campmobile
For people who believe a family's
car should be it's castle ! |
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ac78
Samba Member
Joined: March 18, 2008
Posts: 330
Location: Nashville
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| Posted: Thu Apr 14, 2016 4:37 pm Post subject: Re: Vacuum/Timing questions |
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| Wildthings wrote: |
| The ported vacuum connection for the vacuum advance will not have vacuum at base idle, but should have vacuum if you rev the engine a bit. I guess the port in the throttle body could be clogged with something, but haven't experienced it myself. Can you suck through the vacuum advance hose with it attached to the throttle body, if not remove the throttle body then try blowing through the port both ways with compressed air. |
I am now getting the throttle body vacuum when revving. There was some muck on the butterfly but I didn't think it was that bad.
_________________
78 Westy 2.0l hydr. FI
VW Campmobile
For people who believe a family's
car should be it's castle ! |
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SGKent 
Samba Member
Joined: October 30, 2007
Posts: 41031
Location: Citrus Heights CA (Near Sacramento)
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| Posted: Thu Apr 14, 2016 5:35 pm Post subject: Re: Vacuum/Timing questions |
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| Quote: |
| Many things can affect the vacuum at each of these sources. On the S-boot side for example, a broken S-boot would greatly affect vacuum there at idle and mixtures at all RPM. If the PCV valve is leaky along with a loose valve cover or oil filler cap it can inject significant air into the S-boot that has the same effect as a broken S-boot. |
in other words - check for vacuum leaks on the S-boot side of the throttle body. Also check for sealed valve covers and oil cap etc. Any air leaking in on that side dilutes the ported vacuum.
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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ac78
Samba Member
Joined: March 18, 2008
Posts: 330
Location: Nashville
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| Posted: Mon Apr 25, 2016 5:40 pm Post subject: Re: Vacuum/Timing questions |
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Just an update. Haven't really done anything but drive it. We went Bugapolooza in Chattanooga last weekend and took the scenic highway back to Nashville. Everything was great until I hit the stop light rolling into Murfreesboro. I was greeted by a little red light flicker on the dash when the clutch went in. Seemed to have a lower idle than normal too. The light went out when I hit the gas and I just carried on. I haven't seen the red light since last Saturday. There is still a miss that I can really notice about 35 mph in 3rd. When I filled up yesterday I got 18.5 mpg on my last tank which I was thrilled with. Not burning oil either. Does it seem possible to get that high of gas mileage when #3 cylinder is showing 80lbs on the wet test? I think it's time for a leak down. I'm planning on a trip to Colorado this summer. Any thoughts? Thank you in advance!
Below is a quick video from tonight on timing, idle rpm, dwell, vacuum and my muffler that the last week of backfiring blew out.
https://youtu.be/A9KnlRJ_c7w
Dry test
Wet test
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78 Westy 2.0l hydr. FI
VW Campmobile
For people who believe a family's
car should be it's castle ! |
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Wildthings
Samba Member
Joined: March 13, 2005
Posts: 50332
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| Posted: Mon Apr 25, 2016 8:28 pm Post subject: Re: Vacuum/Timing questions |
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| The rings will seal from the combustion pressure when under way, so power and gas mileage can be just fine even when a compression test shows low compression. |
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timvw7476
Samba Member
Joined: June 03, 2013
Posts: 2196
Location: seattle
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| Posted: Mon Apr 25, 2016 9:56 pm Post subject: Re: Vacuum/Timing questions |
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That unit sounds like it's got 20k left in it.
Idles like a fine Swiss watch,
with a rusty muffler. |
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