# Tri power Fast idle



## Droach6498 (Nov 1, 2020)

Im having my engine etc installed and the guy doing it is having a problem with the idle which is around 2500rpm. Is it or possibly be a vacuum leak. They are 1966 3/2s with a 66 manifold going on my 67 400ci engine in my 65 gto. Engine is bored 60 over so its 460ci now, aluminum heads.


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## geeteeohguy (Feb 2, 2008)

That is not a '66 tripower or intake. It is a '65 with the smaller middle carb and heat tube choke. '66 units have equal sized carbs (center as large as end units) and a heat stove choke on the intake like a Q-jet from '67. Verify timing is not too advanced, and that the throttle blades are closed. Very simple carbs to work on and adjust. Also, the vacuum for the vacuum advance comes from a hollow carb stud mounted to the left rear of the center carb. Do you have the correct 'F" PCV fitting that connects the PCV hose to BOTH intake plenum ports?


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## Droach6498 (Nov 1, 2020)

geeteeohguy said:


> That is not a '66 tripower or intake. It is a '65 with the smaller middle carb and heat tube choke. '66 units have equal sized carbs (center as large as end units) and a heat stove choke on the intake like a Q-jet from '67. Verify timing is not too advanced, and that the throttle blades are closed. Very simple carbs to work on and adjust. Also, the vacuum for the vacuum advance comes from a hollow carb stud mounted to the left rear of the center carb. Do you have the correct 'F" PCV fitting that connects the PCV hose to BOTH intake plenum ports?


No on the F fitting, is that N210M in the Ames cat your meaning? Not sure how it would connect it has 2 steel lines coming out of the manifold to the center carb in the pic. The manifold has a date of 66 on it I beleive I'll have to take another look but Impretty sure. The braided steel on the left of the center carb is connected to the vacuum


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## mcguiremcd (May 23, 2012)

Droach6498 said:


> No on the F fitting, is that N210M in the Ames cat your meaning? Not sure how it would connect it has 2 steel lines coming out of the manifold to the center carb in the pic. The manifold has a date of 66 on it I beleive I'll have to take another look but Impretty sure. The braided steel on the left of the center carb is connected to the vacuum


Sorry but I agree with Geetee. Not a 66.


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## Droach6498 (Nov 1, 2020)

No worries my car is a 65 so it would be a + if it is thats what the owner told me and the date on the manifold ends 66 I dont have it here so I cant verify


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## geeteeohguy (Feb 2, 2008)

The pipes pressed into the manifold connect to the 'F' fitting with short rubber hoses, and the end of the fitting connects to the PCV valve. So, two short hoses, one longer one, so the PCV pulls vacuum from both intake plenums.


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## Droach6498 (Nov 1, 2020)

anyone have a pic of the setup?


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## Droach6498 (Nov 1, 2020)

I just watched a vid of Dave whatever and he said theres the connection to the back of the middle carb that connects to vacuum, where are you supposed to get from what connects to the distributor?
Anyone with some pics would be a great help
Thanks for your help I get the F connection seems like theres alot of vacuum connections


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## geeteeohguy (Feb 2, 2008)

Only one vacuum connection for the vacuum advance, gotten through a hollow carb stud at the LR center carb. Mine is taken off the back of the center carb through a fitting. Been that way for the 40 years I've had the car. Two short PCV hoses going to the fitting, with one hose going from there to the PCV valve. Easy Peasy.


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## PontiacJim (Dec 29, 2012)

Droach6498 said:


> I just watched a vid of Dave whatever and he said theres the connection to the back of the middle carb that connects to vacuum, where are you supposed to get from what connects to the distributor?
> Anyone with some pics would be a great help
> Thanks for your help I get the F connection seems like theres alot of vacuum connections



Check out the "F"fitting and how it goes on the intake - this hooks to the PCV valve in the back of the valley pan.









PCV


There are a pair of 5/16" posts threaded into the intake between the center and rear carbs. Hoses attach to this fitting. The fitting points to the passenger side. A 3/8" hose runs to the PCV valve in the valley pan. The original "F" fittings were plastic. Heat and age have taken their toll and...



pontiactripower.com





The Vacuum advance hose gets attached to a hollow carb stud having threads for the carb hold down nut and a nipple on the end for the hose to be attached. The carb stud hole will go through the manifold and into the open plenum - it is not a "blind hole" where the hole is sealed off. This way the manifold vacuum pulls through the hollow stud to create the needed vacuum for the vacuum advance. So you will be removing 1 of your solid carb studs and substituting it for the hollow stud for the vacuum advance hose connection.









1965 Hollow Carb Stud


Not available elsewhere. The 65 hollow stud is shorter than the 66, which is sold by others. Also, it is located in a different position that the 66. In 65, it is located in center carb.passenger side, rear. If your A body has air conditioning, the hollow stud is a vacuum source for air...



pontiactripower.com





I would suggest another mechanic who knows how to work on older cars as most of this is very basic and easy to research on the internet.


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## Droach6498 (Nov 1, 2020)

PontiacJim said:


> Check out the "F"fitting and how it goes on the intake - this hooks to the PCV valve in the back of the valley pan.
> 
> 
> 
> ...



Thanks. I would and wanted to use someone familiar with Pontiacs but here in the SF bay area its crazy ridiculous most charge $200-$250 hr and its 6 months to a year until they can even look at it. I was lucky to find this guy. Found him through Bob Oliver of comp carbs hes super busy too took mine on right away has done alot of work getting things together, he builds race cars dirt track chevys
hes way the hell out in the sticks on a farm
I know about the F bracket Im ordering one its all the other vacuums like front of center carb theres a port, on the side of the carb is another where do they need to be connected? One for the power brake booster and the other ? Couldnt one goto the vacuum advance?
I just looked at Pontiac tri power they show the power brake booster coming off th center carb vacuum, I think thats what it looks like.
Thanks again for your time
Lost


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## Droach6498 (Nov 1, 2020)

More thinking
How many of these vacuum ports are there? Is there anywhere where they show all this in a drawing? I want to show the mechanic and it helps me understand.


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## Droach6498 (Nov 1, 2020)

geeteeohguy said:


> Only one vacuum connection for the vacuum advance, gotten through a hollow carb stud at the LR center carb. Mine is taken off the back of the center carb through a fitting. Been that way for the 40 years I've had the car. Two short PCV hoses going to the fitting, with one hose going from there to the PCV valve. Easy Peasy.
> View attachment 155475
> View attachment 155475
> View attachment 155476
> View attachment 155477


By LR I assume driver side rear. I hate to be fussy but some of the pics are way to big I dont know whats what in them but thanks for your hellp its all good Im learning


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## O52 (Jan 27, 2019)

The service manuals usually have good pictorial diagrams of the engine and its components. PCV will probably found in the emissions chapter 6D


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## geeteeohguy (Feb 2, 2008)

What Jim said. This is one of the simplest vacuum lay-outs in history. Recommend educating yourself with available on-line vacuum diagrams, books, etc. Research and learning is a huge part of the fun with these old cars. If your car has power brakes, the vacuum needs to come off the back of one of the carbs. If it has an automatic, the vacuum needs to come off the the center carb below the throttle plates (manifold vacuum). The PCV vacuum comes off the F fitting (not bracket....it's a vacuum fitting, not a mount), and the distributor needs to come off the hollow stud. I lived in Oakland from '69 to '03....if I were still there I would show you where it all goes for free.


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## Droach6498 (Nov 1, 2020)

O52 said:


> The service manuals usually have good pictorial diagrams of the engine and its components. PCV will probably found in the emissions chapter 6D


I have the resto mod 64-72 but it really sucks I get more info looking at pics on Ames than it
So far I have the F connectors, then I guess Im supposed to remove a carb bolt and replace with a hollow bolt and that vacuum goes to my brake booster or vac advance
1) F port to PCV valve
2) Hollow bolt to vacuum advance
3) What feeds brake booster? any other vacuum port I guess?
A diagram would be great or a video. Surprised no one has done a vid on exactly how everything goes. I got some info off Youtube from Dave so& so, but his info about the F tube is all nothing about a hollow bolt, he doesnt answer questions.
Can you reccomend a service manual that has tri power setup? hate to by something then return it
TY u all very very much


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## geeteeohguy (Feb 2, 2008)

Hard to see, but looks like your PCV is hooked up to one plenum of the intake and the power booster is hooked up to where the other PCV hose should be. Not optimal. As Jim said, you need someone familiar with these cars.


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## geeteeohguy (Feb 2, 2008)

Look at the back of the carbs, at the base-plates. The cast iron part that mounts to the intake. Either the center or rear carb. Should be a pipe plug there. That gets replaced with a nipple for the brake booster hose. It's 1/2" or so. You'll never get vacuum for the booster from a carb stud...it's too small and for the distributor vac advance only.


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## geeteeohguy (Feb 2, 2008)

So, F-fitting to PCV valve (three hoses). Rear of carb big fitting to brake booster. (one hose) Hollow stud to vac advance (one small hose). If a manual trans, that's all there is. If auto trans, need manifold vacuum to the trans modulator. Can also be off another stud or tee-d into the back of one of the carb bases.


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## Droach6498 (Nov 1, 2020)

geeteeohguy said:


> What Jim said. This is one of the simplest vacuum lay-outs in history. Recommend educating yourself with available on-line vacuum diagrams, books, etc. Research and learning is a huge part of the fun with these old cars. If your car has power brakes, the vacuum needs to come off the back of one of the carbs. If it has an automatic, the vacuum needs to come off the the center carb below the throttle plates (manifold vacuum). The PCV vacuum comes off the F fitting (not bracket....it's a vacuum fitting, not a mount), and the distributor needs to come off the hollow stud. I lived in Oakland from '69 to '03....if I were still there I would show you where it all goes for free.


I talked to John at Pontiac Tri Power and Ive got it all figured out and the mechanic actually has it all together OK I think. The 2 mani ports he has one to PCV valve and the other to brake booster and others are capped. Dont need vacuum advance doesnt have it. Soif thats all OK its leaking elseware. Maybe PCV valve is bad its the one that came with the carbs & mani so get a new one, gaskets could be bad they're old he didnt see the new ones provided by Comp carbs
Think that setup is OK? He thinks so 
It is easy if you know all that stuff, hollow stud, F bar


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## geeteeohguy (Feb 2, 2008)

Set up is NOT ok, as the port your mechanic is using for a brake hose is _supposed_ to be a PCV port used _in tandem _with the OTHER PCV port to _get proper scavenging_. Not running vacuum advance on a street driven car is pretty much unheard of, as it causes overheating and excessive fuel consumption. If your 'mechanic' is ok with this he is not a mechanic IMO. I am not the sharpest tool in the shed, but I am a retired ASE Master Auto Tech with 42 years in the business and a licensed smog check tech for 40 years, 1981-2021. Have owned and driven tripower first gen GTO's since the 1970's non stop and still do. This is my last post in this thread. Good luck to you, Sir.


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## Gtowally (Jan 19, 2019)

Also if not previously addressed if the throttle plates are not closed tight on the 2 end carbs you will have a massive. vacuum leak…..high idle


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## Zeypher69 (Dec 25, 2020)

Droach6498 said:


> Thanks. I would and wanted to use someone familiar with Pontiacs but here in the SF bay area its crazy ridiculous most charge $200-$250 hr and its 6 months to a year until they can even look at it. I was lucky to find this guy. Found him through Bob Oliver of comp carbs hes super busy too took mine on right away has done alot of work getting things together, he builds race cars dirt track chevys
> hes way the hell out in the sticks on a farm
> I know about the F bracket Im ordering one its all the other vacuums like front of center carb theres a port, on the side of the carb is another where do they need to be connected? One for the power brake booster and the other ? Couldnt one goto the vacuum advance?
> I just looked at Pontiac tri power they show the power brake booster coming off th center carb vacuum, I think thats what it looks like.
> ...


I have heard that so many times and I will never understand why "he builds race car motors" means he's a good mechanic. Do you have a race car?
I'm not too far from you, Santa Rosa, and I gave been a mechanic 45 years and thanks to my dad working on Pontiacs even longer.
I'm down to only one now, 64 GTO tripower 4 speed convertible.
I would happy to help you out but gas is expensive in California!
Sounds the guy working on is lost.


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## Droach6498 (Nov 1, 2020)

Zeypher69 said:


> I have heard that so many times and I will never understand why "he builds race car motors" means he's a good mechanic. Do you have a race car?
> I'm not too far from you, Santa Rosa, and I gave been a mechanic 45 years and thanks to my dad working on Pontiacs even longer.
> I'm down to only one now, 64 GTO tripower 4 speed convertible.
> I would happy to help you out but gas is expensive in California!
> Sounds the guy working on is lost.


I had no other chioce I contacted at least 8 mechanics/ shops they all were to busy didnt want my project, which wasnt really much installing the radiator to differential, it would be done if it wasnt the vacuum leaks, I about 90% sure its the throttle ates and possibly the throttle arm seals, etc they're old catbs probably never had any work done until I sent them to Comp Carbs in NV which I dont think he really had a clue about the vacuum of these carbs, I sent him an email yesterday asking if he addressed that at all Im waiting to hear what he says.
He is lost a little but hes doing the best he can its down to just this problem I have done alot of research so I know how to test for vac leaks, a bit, I ordered the correct parts for the vacuum lines when I get them Im going to install them test it if it still persists the only thing I can do is send them off to Pontiac tri power, John Wright, have him fixem and then install and go from there. 
Santa Rosa is a long way from Walnut Creek i woud be glad topay you have you help possibly when I getthrough all this if it still persists I'll let you know. Send me an email or TM if you like I wont contact you unless I have to [email protected]/ 925-575-1892
And Thanks for youe help


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