# Question about GA16i throttle body



## ahardb0dy (Nov 9, 2003)

So I discovered last night that I have a water leak on the front of the TB where the 2 rubber hoses attach, these are the 2 hoses that come up from under the intake manifold. The TB has two 90 degree fittings that the rubber hoses connect to and the one on the right side also has a metal nipple that sticks up straight and a hose connects to it and goes to the thermal element.

My leak is from the metal nipple that sticks up, actually the nipple part broke off.

So my question, why does the TB have water flowing into it? Wouldn't the warm/hot water effect the performance by heating everything?

Looking on Nissan Fast it appears I can purchase the bottom half of the TB which should have these fittings in it for about $50, local junkyard is not showing any sentra's of pulsar's that would have the GA16i engine and did not see any on E-bay.

thanks


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## smj999smj (Jan 1, 2006)

The throttle body has a thermo element (also referred to as a "wax kit") used to control cold start fast idle, which is heated by the flow of coolant through the thermo element's housing. The wax expands or contracts depending on coolant temperature.


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## ahardb0dy (Nov 9, 2003)

Ok, just took somepics to explain what I'm talking about:

the two fittings where the hoses coming thru the manifold attach too:










the hose on the right goes to the thermo element, it is sitting on the fitting in this pic because the metal nipple it is supposed to slide over broke off:











pic showing the two hoses coming from under the manifold:










the thermo element, looks like there may have been/still may be a leak there due to the green corrosion:


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## smj999smj (Jan 1, 2006)

I wish the Nissan part catalog images showed the other side! At first I thought it was part of the $55 air horn assy., P/N: 16266-84A10. They have a N.O.S. air horn on Ebay for $25 with a new wax kit:

NEW 88 - 90 NISSAN SENTRA PULSAR NX CARBURETOR AIR HORN | eBay

BUT, the more I look at your pic, I think it's the "throttle body" of the TBI unit that you need, P/N: 16119-84A10 which is showing for $242 online. 

Have you tried searching for a used one at Car-part.com?


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## ahardb0dy (Nov 9, 2003)

I thought it was the air horn part number also, No didn't go to that site. Went to junkyard today but they only had one sentra and it wasn't the GA16I engine. So I had an idea to bypass the connections on the TB but still have the hose go to the thermo element.

Hard to see in my picture below but what I did was I bought the following:
1/2" brass tee
two 1/2" x 3/8" barb fittings 
1/2" x 1/4" barb fitting
1/2" street elbow

I assembled it so the tee was facing with one opening up, down and to the left, than screwed the street elbow into the tee on the left opening, than installed the two 3/8" barb fittings pointing down, and the 1/4" barb fitting facing up. I put the 2 hoses from under the intake manifold onto the two 3/8" barb fittings with the factory clamps and than put the hose going to the thermo element onto the 1/4" barb fitting, again with the factory clamp. This way it bypasses the TB but still feeds the thermo element.

Only problem I had is both upper ends of the hoses from under the intake manifold had leaking ends so I had to cut about 3/4" off the ends.

Everything looks good if anything I have a very small drip but I'll probably replace the factory clamps with regular hose clamps.

Than after bolting the TB back on and plugging everything back in, went to start the car and nothing!! Couldn't figure out why it wouldn't start so I was looking at the injector wondering if it was getting power and I followed the wires right to the connector that wasn't plugged IN !! DUH !!, plugged that in and it fired right up.

here's the pic I took:


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## ahardb0dy (Nov 9, 2003)

so why does coolant flow thru the TB anyway?


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## smj999smj (Jan 1, 2006)

I'm sure they had their reason; I just can't tell you what it is!


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## ahardb0dy (Nov 9, 2003)

Come on now, I was waiting for an answer from you ! LOL

Someone I work with said maybe it's to cool it but I said how could it cool the TB when it has hot coolant running thru those lines??


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## smj999smj (Jan 1, 2006)

Engine coolant runs about 190 degrees F. So, I guess the question is how hot does the throttle body get sitting on top of the engine? I don't really see the TBI unit needing to be cooled, either, as all it is doing is serving as an entryway for the air entering the engine, a mounting point for the MAS and TPS, as well as the fuel injector. You'll have to find an old Nissan engineer and ask him, so study up on your Japanese!


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## ahardb0dy (Nov 9, 2003)

ありがとう (thank you)


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## Crazy-Mart (Jul 14, 2002)

coolant goes heat up the TB because : at really low temps (mostly where i live) the TB plate could built ice from condensation (hot air coming in/over below 0 thin metal sheet) could block/make operation difficult for the TB to move freely... waths it do really is keep the metal hot/as per motor temp to keep it going freely ...

as you can see, those hose are just a loop that goes in and out the TB and are on all nissan engine and mostly all engine there is ! ...

PERF note : just get rid of it !! and if you run in hot weither it just wont hurt anything.. i used to ditch the fuel evaporator too (brown thing sandwiched in the TBI unit that as some kind of injection plug receiving 12volt but that another story)


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## ahardb0dy (Nov 9, 2003)

So I guess down here in Hot as hell Florida your saying I don't need the TB to be warmed up? LOL

The thing under the TB is the mixture heater


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## Crazy-Mart (Jul 14, 2002)

ahardb0dy said:


> So I guess down here in Hot as hell Florida your saying I don't need the TB to be warmed up? LOL
> 
> The thing under the TB is the mixture heater


mostly  ... ive been running my e16i without those and without issues... old memories  actually it is complementary to the water passage in the intake manifold runners... performance wise, nowadays, peeps just go on with thermospacer on their intake, wich cant be done to the old e16/ga16i because of the water passage in the intake (has to confirm the ga taught) mixture heater is somewath usefull as it keeps the fuel in gazeous form while travelling to the head... (wich make for a better burned fuel) old technology


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