Technical Tube that goes from air filter to engine.

[chinman01]

Hi,

I recently bought a Fiat Punto MK1 and its missing a tube (or hose) that goes from the air filter to the engine. I've been looking in the internet but wasn't able to find it.

Anyone know what's the name of that tube or where I can find it?

Thanks!

 

[Eklipze3k]

Welcome.

A picture would help, if you can use the attachments feature to upload one. If I had to guess though, I'd say we're talking about the breather hose? Which engine do you have?

 

[chinman01]

Hi,

My engine is a 1.1 (The car's a Punto 55 sx).
I don't have pictures of my car specifically as I don't have it with me right now, but here are some pictures indicating the tube I'm talking about:

 

[Eklipze3k]

Ahh you mean the metal tube at the front? Don't worry about it, it's not necessary except in very cold climates! It helps the engine warm up faster by drawing heat from the exhaust manifold. Engine can quite happily run without it, unless you plan to move to Norway or Iceland

 

[chinman01]

Yeah, the white tube in the image. Can't it affect fuel consumption?

Also, can it be the cause of high rpms (in the 2000s) when I first turn the car on?

 

[Eklipze3k]

No, and no. It does nothing special other than provide a little warmth to the air to aid initial warmup in cold climates.

If you're over-revving on startup you have another issue, and whatever it is may well be linked to greater fuel consumption. This is outside of my expertise though.

 

[chinman01]

Ok, thank you very much!

 

[blu73]

high idle is usually a vacuum leak so check all the vac cum lines, there is a nice diagram showing where they all go to from the throttle body in the guides section

 

[chinman01]

Will do, thanks!

 

[g8rpi]

Ahh you mean the metal tube at the front? Don't worry about it, it's not necessary except in very cold climates! It helps the engine warm up faster by drawing heat from the exhaust manifold. Engine can quite happily run without it, unless you plan to move to Norway or Iceland

Hi,
Not totally correct. It does not aid warm up much. The primary purpose of the warm air inlet is to prevent ICE forming in the venturi of the carburetter. This can happen even when the air temerature is above freezing. The air and any moisture in it is cooled by the pressure drop and latent heat of vapourisation of the fuel in the venturi and ice builds up. This leads to a gradual loss of power until you have wide open throttle but no power. You stop the car scratch your head looking at the engine for a bit, try again and it's OK because the ice has melted.
It only affects carburetter engines whichis why you don't see it on modern cars or Diesels. There should be a flap in the air box that is thermostatically controlled (some have vacuum assistance). The flap opens at low temperatures. Some cars had a manual flap or rotatable inlet that you had to change for winter or summer.
It will work without the hose but best to fit it. It is a generic aluminium flexible heater hose or duct, just check the diameter of the spigots it pushes over. A good parts supplier should have it or try ebay.
Anytime you have cool moist air you can get carburetter icing, it kills several people every year. Google carb ice aircraft or ask a light aircraft pilot.

Robert G8RPI

 

[Eklipze3k]

OK, but the 55 is Injection, not carb. The same engine as in my Sei sporting, which also had this heat transfer pipe, and is also injection.

 

[blu73]

:yeahthat: and they run coolant through the throttle body too

 

[g8rpi]

OK, but the 55 is Injection, not carb. The same engine as in my Sei sporting, which also had this heat transfer pipe, and is also injection.

I assume that is single point (throttle body) injection. This is essentially the same as a carburetter and can still suffer from icing. While there is no (or very little) venturi effect, the cooling caused by the fuel evaporating causes the icing. I consider single point injection as an electronically controlled carburetter rather than true injection. Multipoint systems do not have warm air inlet. There may be exceptions for extreme climates.

Robert G8RPI.

 

[rolandbrindley]

On my 1994 Punto 55 I removed and discarded all the heater tinware and pipe related to the warm air intake, and glued shut the flap underneath the air filter body. In the climate of southern Spain it does nothing. I would probably do the same if I had my car in UK or in a cooler climate. If it was in Canada or Russia I would leave it alone.

 

[g8rpi]

The UK is cold enough for carb icing, I've had it happen to me. It can happen well over 10 deg C if the humidity is high enough. Anywhere in the red below can cause carb icing.

It could even happen in southern europe.


Robert G8RPI.

 

[Eklipze3k]

I take your point on board Robert, but anecdotal evidence suggests that absolutely none of the Cinq's and Sei's (which share the exact same setup as the P55), which have had the air filter system modified to not have this heat transfer pipe have ever had an issue. In the 10 years I've been on this forum I've never heard anyone mention it even once. Also, as blu73 mentions, the throttle body has coolant channels through it, which should keep it plenty warm enough to prevent icing.

 

[g8rpi]

Agreed, and I'm not saying a Cinq or Sei will suffer from icing. It's just that it's counter intuative for it to happen above freezing outside and there is seldom any evidence of what happened. Often the driver won't even know, they just press the throttle a little harder to compensate for the power loss. Fiat would not have put the plate, hose, flap and actuator in there if they did not think it was needed needed The water jacket only helps when the engine has warmed up.

Robert G8RPI.