| Vacuum lines [message #297064] |
Thu, 10 March 2016 05:59  |
tgeiger
Messages: 518
Registered: February 2006
Location: kansas city
Karma: -1
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Senior Member |
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Good morning GMC'rs,
Have a question on the vacuum system. I've been having issues with the motor home staying in 2nd and not shifting to 3rd, or I will be in 3rd and at the slightest grade it kicks down to 2nd and revs up high. I'm checking the vacuum system and noticed a couple things. I still have the TVS switch, which some I read have gotten rid of. And looking to the other vacuum port to the left of the carb, the one with 2 ports, I believe the bigger hose goes down to the transmission and the other smaller one is plugged? It is not plugged. Would that cause the shifting issue? Also, was thinking of going through and replacing vacuum lines throughout just to tune it up and make it the best it can be. Some hoses look a bit dried out from engine heat. Oh also, there seems to be a hose just dangling loose that leads down to the charcoal canister. Should that be hooked up?
Tom Geiger
76 Eleganza II
KCMO
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| Re: Vacuum lines [message #297070 is a reply to message #297064] |
Thu, 10 March 2016 07:41  |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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tgeiger wrote on Thu, 10 March 2016 06:59Good morning GMC'rs,
Have a question on the vacuum system. I've been having issues with the motor home staying in 2nd and not shifting to 3rd, or I will be in 3rd and at the slightest grade it kicks down to 2nd and revs up high. I'm checking the vacuum system and noticed a couple things. I still have the TVS switch, which some I read have gotten rid of. And looking to the other vacuum port to the left of the carb, the one with 2 ports, I believe the bigger hose goes down to the transmission and the other smaller one is plugged? It is not plugged. Would that cause the shifting issue? Also, was thinking of going through and replacing vacuum lines throughout just to tune it up and make it the best it can be. Some hoses look a bit dried out from engine heat. Oh also, there seems to be a hose just dangling loose that leads down to the charcoal canister. Should that be hooked up?
Tom,
Yes, that hose should be connected, but if you don't have a sigfile please include the specifics of your coach.
Yes, all the vacuum lines are cooked after 40 years in the heat.
Another good chance is that the restriction in the steel kick-down line to the modulator is plugged or the little piece of rubber that does the connection there is cracked.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: [GMCnet] Vacuum lines [message #297073 is a reply to message #297070] |
Thu, 10 March 2016 08:30 |
Mr ERFisher
Messages: 7117
Registered: August 2005
Karma: 2
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Senior Member |
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Ask manny
On Thursday, March 10, 2016, Matt Colie wrote:
> tgeiger wrote on Thu, 10 March 2016 06:59
>> Good morning GMC'rs,
>> Have a question on the vacuum system. I've been having issues with the
> motor home staying in 2nd and not shifting to 3rd, or I will be in 3rd and
>> at the slightest grade it kicks down to 2nd and revs up high. I'm
> checking the vacuum system and noticed a couple things. I still have the TVS
>> switch, which some I read have gotten rid of. And looking to the other
> vacuum port to the left of the carb, the one with 2 ports, I believe the
>> bigger hose goes down to the transmission and the other smaller one is
> plugged? It is not plugged. Would that cause the shifting issue? Also, was
>> thinking of going through and replacing vacuum lines throughout just to
> tune it up and make it the best it can be. Some hoses look a bit dried out
>> from engine heat. Oh also, there seems to be a hose just dangling loose
> that leads down to the charcoal canister. Should that be hooked up?
>
> Tom,
>
> Yes, that hose should be connected, but if you don't have a sigfile please
> include the specifics of your coach.
> Yes, all the vacuum lines are cooked after 40 years in the heat.
> Another good chance is that the restriction in the steel kick-down line to
> the modulator is plugged or the little piece of rubber that does the
> connection there is cracked.
>
> Matt
> --
> Matt & Mary Colie - Members GMCMI, GMCGL, GMCES
> '73 Glacier 23 - Still Loving OE Rear Drum Brake with Applied Control Arms
> Now with both true Keyless and remote entry
> SE Michigan - Twixt A2 and Detroit
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html
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