no_3of4

I have a 86 toyota truck, 4x4 22re, I noticed that there is a water line that runs through the throttle body on the intake. Is there any need to have this on there. My thinking is its for heating the air but wouldnt cooler air make for better running? Please give some input on this.

Flash319

It is not for heating or cooling it is to operate the high idle bypass. The coolent temperature makes a plunger close as it heats up causing the cold idle to drop.

no_3of4

ok, thanks for the information.

thook

Yep, it's there for a very good reason. You don't want to remove it.

91diesel

I removed mine on my diesel with no problems and honda racers do it a lot too. Google search the throttle body bypass and you'll see. Some claim problems, some do not. I've noticed much cooler intake temps on my truck which is a good thing.

Matt16

How does it ever run properly on cold starts then? If the intake is too cold (as in a cold start on a cold morning) the gas burns very inefficiently and the motor barely runs. The Idle Air Bypass opens an alternate passage around the throttle plate so more air (and thus gas) can get into the cylinder and the engine can run properly. Once the engine warms up, it takes a lot less fuel/air to idle. When the thermostat is closed (cold engine), the Idle Air Bypass is open (and vice versa) and more air can get by.

Maybe this works in Florida, Arizona, Texas where it is always unbearably hot, but I have my doubts you'd be happy with that mod in Canada or the colder states.

Maybe that wor

91diesel

Keep in mind mine is a diesel so I have no idea what you mean by proper air/fuel ratios or throttle plates?! :-)

I only know about doing this on a gas motor from the honda forums. You are probably right about trying this in Canada, although one poster did say he was in Colorado and had no problem at all. Some reported weird idling.............

Flash319

If you take it off a 22re you will have a 1800rpm idle all the time.......

annoyingrob

I always thought it was to keep the throttle from icing up in the cold. All my Toyotas have had them, even ones with electronic ISCVs.

abecedarian

On a Diesel engine, its purpose is to warm the air as it enters the engine, no more nor no less. Diesels are 'compression ignition' and the warmer the air entering the engine is, the easier it is to ignite the fuel mixture.

On a Gasoline engine, a more rich mixture when cold and consequently a higher idle speed helps them warm up more quickly. The ECU will add extra fuel (after the cold start system has done its job getting the engine started) but they still like a little higher idle speed until things start to warm up.

no_3of4

well i do live in Texas and on average the temp is warm, however this past deer season it was never above 25F for 5 days and below 0 at night. so i do belive i will be leaving the line on there. Thanks for all the information on this.