Stock arrangement of emission hoses - The 1947 - Present Chevrolet & GMC Truck Message Board Network

gman · 07-19-2004, 11:55 PM

Does anyone have a layout with pictures of the proper routing and location
of the emission hoses on a '72 with a 350 motor and quadrajet? I'm
referring to the hoses coming from and going to the charcoal
canister........I know the vent line from the gas tank goes to the "gas"
connection on the canister. But I'm uncertain of the exact routing of the
other two. I know they attach to the carb but not sure how. Can't find
specifics in the service manual. Any help would be greatly appreciated.

Thanks.

cdowns · 07-20-2004, 12:32 AM

the assembly manual has those pictures maybe somebody can scan them for you

71-longbed · 07-20-2004, 02:35 AM

i wouldnt mind that either .. just to make sure mine are running right

Harold Shepard · 07-20-2004, 12:03 PM

The hose that comes from the canister to the carb 1/4 line gets a tee fitting and ties into the pvc system at the front of the carb. The smaller vaccum line attaches at the higher ported vac. port on the carb. On the 4mv carb the vac. advance should attach at the port on the lower right and the canister should attach at upper left port on the carb.

gman · 07-22-2004, 02:15 PM

I've got a factory assembly manual and I can't find a pic of it in there anywhere.

Harold..........I do have the 4MV q-jet. Just so I understand then......the 1/4 inch line goes into a "T" fitting that will also have the line from the PVC line going into the "T", which will then go into the unported vacuum at the bottom of the carb. The smaller 3/16 inch line goes where? I have the original air cleaner and I thought one of those lines from the canister attached to the air cleaner? Anybody else?

71-longbed · 07-22-2004, 02:30 PM

the air cleaner hooks to the passenger side port on the carb... mine is capped in the pic... i believe the rest of the hoses are stock ... hope this helps let me know if anyone has it diferently .. notice the tee on the pcv hose

Harold Shepard · 07-22-2004, 08:36 PM

If you look at 71 longbed's pic, the capped port is for the door located in the stock air cleaner, as he said. The tee is correct, mine is located closer to the port, personal preference looks a little cleaner, the 3/16 hose FROM the canister should attach to the port just above the fuel inlet fitting, not tho be confused with the one for the choke pull-off almost directly behind the fitting and the vaccumn advanve should hook to the port on the driver's side next to the fast idle solenoid. Hope that helps you out.

gman · 07-22-2004, 10:20 PM

Thank you very much.

71-longbed · 07-23-2004, 01:28 AM

my vacuum advance comes from the a port on the fast idle solenoid ... i know it works *becuase i've always had it that way".... does anyone know if there are any advantages or disadvantages to tweaking with the stock setup ??

CaperCat · 07-26-2004, 11:07 PM

Thanks for the emission hose lesson. I just need one more thing; There are two vacuum ports on the A/C solenoid. What connects to those ports and all should be well. I too have a '71 350 with A/C. Thanks.

Steve

71-longbed · 07-27-2004, 04:13 AM

ok .. is it a ac solenoid or a fast idle ....fast idle cams on the passenger side ...
i'fe heard that solenoid called many diferent things .... according to gm its a idle control solenoid... but some tell me its AC related ... which is it ...

CaperCat · 07-27-2004, 09:09 AM

That solendoid only kick in when the A/C is turned on. That's why you do not adjust the fast idle speed with this solenoid. It is an idle control solenoid used when the A/C is turned on. It compensates for the extra load on the engine to run the A/C compressor.

We have the same truck, except mine is light red and white and stock.

71-longbed · 07-27-2004, 11:25 AM

ok ..now my question is .. my truck doesn't have AC ... can i bypass the solenoid some how ??

Harold Shepard · 07-27-2004, 01:42 PM

Capercat, Which side of the intake is the solenoid you are talking about on? The solenoid on the carb is a fast idle solenoid, but it should only have an electical connection on it. If the solenoid is on the passenger side, it may be the TCS solenoid. If this is the case it connects by a flat conector to the transmission and attaches to the distributer's vacumn line- I think the nipple that points up is the in - and the nipple that points to the front goes to the vacumn port on the carb. 71 longbed the solenoid is a fast idle solenoid and you can unhook it, it was put in place to the prevent run on and spark knock after the engine was shut down as well as a load compensator when things lie a/c were in place to prevent the idle speed from falling too low- has something to do with the lean drop issue in the carb- GM was detuning everything to meet new emission standards that started in 71 and carried forward.

07-19-2004, 11:55 PM	#1
gman Registered User Join Date: Nov 2000 Location: Ogden, Utah Posts: 290	Stock arrangement of emission hoses Does anyone have a layout with pictures of the proper routing and location of the emission hoses on a '72 with a 350 motor and quadrajet? I'm referring to the hoses coming from and going to the charcoal canister........I know the vent line from the gas tank goes to the "gas" connection on the canister. But I'm uncertain of the exact routing of the other two. I know they attach to the carb but not sure how. Can't find specifics in the service manual. Any help would be greatly appreciated. Thanks. __________________ 72 Chevy SWB Custom Deluxe K10, 350/SM465, PS, PB, Fact. Air 2000 Harley...Wide Glide

07-20-2004, 12:32 AM	#2
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	the assembly manual has those pictures maybe somebody can scan them for you __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

07-20-2004, 02:35 AM	#3
71-longbed Its Magically Delicious Join Date: Jan 2003 Location: oregon Posts: 2,398	i wouldnt mind that either .. just to make sure mine are running right __________________ 71 C10 LWB 350sbc -TH350 12 bolt 3.42 Posi Of all my favorite things to do, The utmost is to have a brew. My love grows for my foamy friend, with each thirst-quenching elbow bend. Beer so frosty, smooth, and cold it's paradise pure liquid gold. Yes beer means many things to me that's all for now cus I gotta pee.

07-22-2004, 02:15 PM	#5
gman Registered User Join Date: Nov 2000 Location: Ogden, Utah Posts: 290	I've got a factory assembly manual and I can't find a pic of it in there anywhere. Harold..........I do have the 4MV q-jet. Just so I understand then......the 1/4 inch line goes into a "T" fitting that will also have the line from the PVC line going into the "T", which will then go into the unported vacuum at the bottom of the carb. The smaller 3/16 inch line goes where? I have the original air cleaner and I thought one of those lines from the canister attached to the air cleaner? Anybody else? __________________ 72 Chevy SWB Custom Deluxe K10, 350/SM465, PS, PB, Fact. Air 2000 Harley...Wide Glide

07-22-2004, 02:30 PM	#6
71-longbed Its Magically Delicious Join Date: Jan 2003 Location: oregon Posts: 2,398	the air cleaner hooks to the passenger side port on the carb... mine is capped in the pic... i believe the rest of the hoses are stock ... hope this helps let me know if anyone has it diferently .. notice the tee on the pcv hose Attached Images __________________ 71 C10 LWB 350sbc -TH350 12 bolt 3.42 Posi Of all my favorite things to do, The utmost is to have a brew. My love grows for my foamy friend, with each thirst-quenching elbow bend. Beer so frosty, smooth, and cold it's paradise pure liquid gold. Yes beer means many things to me that's all for now cus I gotta pee.

07-20-2004, 12:03 PM	#4
Harold Shepard Registered User Join Date: May 2004 Location: Canton North Carolina Posts: 466	The hose that comes from the canister to the carb 1/4 line gets a tee fitting and ties into the pvc system at the front of the carb. The smaller vaccum line attaches at the higher ported vac. port on the carb. On the 4mv carb the vac. advance should attach at the port on the lower right and the canister should attach at upper left port on the carb.

07-22-2004, 08:36 PM	#7
Harold Shepard Registered User Join Date: May 2004 Location: Canton North Carolina Posts: 466	If you look at 71 longbed's pic, the capped port is for the door located in the stock air cleaner, as he said. The tee is correct, mine is located closer to the port, personal preference looks a little cleaner, the 3/16 hose FROM the canister should attach to the port just above the fuel inlet fitting, not tho be confused with the one for the choke pull-off almost directly behind the fitting and the vaccumn advanve should hook to the port on the driver's side next to the fast idle solenoid. Hope that helps you out.

07-22-2004, 10:20 PM	#8
gman Registered User Join Date: Nov 2000 Location: Ogden, Utah Posts: 290	Thank you very much. __________________ 72 Chevy SWB Custom Deluxe K10, 350/SM465, PS, PB, Fact. Air 2000 Harley...Wide Glide

07-23-2004, 01:28 AM	#9
71-longbed Its Magically Delicious Join Date: Jan 2003 Location: oregon Posts: 2,398	my vacuum advance comes from the a port on the fast idle solenoid ... i know it works *becuase i've always had it that way".... does anyone know if there are any advantages or disadvantages to tweaking with the stock setup ?? __________________ 71 C10 LWB 350sbc -TH350 12 bolt 3.42 Posi Of all my favorite things to do, The utmost is to have a brew. My love grows for my foamy friend, with each thirst-quenching elbow bend. Beer so frosty, smooth, and cold it's paradise pure liquid gold. Yes beer means many things to me that's all for now cus I gotta pee.

07-26-2004, 11:07 PM	#10
CaperCat Registered User Join Date: Sep 2003 Location: Concord, North Carolina 28027 Posts: 64	Thanks for the emission hose lesson. I just need one more thing; There are two vacuum ports on the A/C solenoid. What connects to those ports and all should be well. I too have a '71 350 with A/C. Thanks. Steve

07-27-2004, 04:13 AM	#11
71-longbed Its Magically Delicious Join Date: Jan 2003 Location: oregon Posts: 2,398	ok .. is it a ac solenoid or a fast idle ....fast idle cams on the passenger side ... i'fe heard that solenoid called many diferent things .... according to gm its a idle control solenoid... but some tell me its AC related ... which is it ... __________________ 71 C10 LWB 350sbc -TH350 12 bolt 3.42 Posi Of all my favorite things to do, The utmost is to have a brew. My love grows for my foamy friend, with each thirst-quenching elbow bend. Beer so frosty, smooth, and cold it's paradise pure liquid gold. Yes beer means many things to me that's all for now cus I gotta pee.

07-27-2004, 09:09 AM	#12
CaperCat Registered User Join Date: Sep 2003 Location: Concord, North Carolina 28027 Posts: 64	That solendoid only kick in when the A/C is turned on. That's why you do not adjust the fast idle speed with this solenoid. It is an idle control solenoid used when the A/C is turned on. It compensates for the extra load on the engine to run the A/C compressor. We have the same truck, except mine is light red and white and stock.

07-27-2004, 11:25 AM	#13
71-longbed Its Magically Delicious Join Date: Jan 2003 Location: oregon Posts: 2,398	ok ..now my question is .. my truck doesn't have AC ... can i bypass the solenoid some how ?? __________________ 71 C10 LWB 350sbc -TH350 12 bolt 3.42 Posi Of all my favorite things to do, The utmost is to have a brew. My love grows for my foamy friend, with each thirst-quenching elbow bend. Beer so frosty, smooth, and cold it's paradise pure liquid gold. Yes beer means many things to me that's all for now cus I gotta pee.

07-27-2004, 01:42 PM	#14
Harold Shepard Registered User Join Date: May 2004 Location: Canton North Carolina Posts: 466	Capercat, Which side of the intake is the solenoid you are talking about on? The solenoid on the carb is a fast idle solenoid, but it should only have an electical connection on it. If the solenoid is on the passenger side, it may be the TCS solenoid. If this is the case it connects by a flat conector to the transmission and attaches to the distributer's vacumn line- I think the nipple that points up is the in - and the nipple that points to the front goes to the vacumn port on the carb. 71 longbed the solenoid is a fast idle solenoid and you can unhook it, it was put in place to the prevent run on and spark knock after the engine was shut down as well as a load compensator when things lie a/c were in place to prevent the idle speed from falling too low- has something to do with the lean drop issue in the carb- GM was detuning everything to meet new emission standards that started in 71 and carried forward.



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