IAC Question

[silver93sho]

So does the IAC need the coolant that runs through the block that it is bolted to it function properly? I left those hoses off when i bypassed my TB last weekend...engine surges to 2k at startup and idles rough, like 400~1k. I already tried the idle reset also. Would like to know since im taking her back apart this week due to a massive oil leak (4qts. from sat. to monday, i think a cam seal let go or wasnt properly seated) and ill have the intake off so if i need to have those coolant hoses hooked up ill do that.

 

[hawkeye18]

nope. In fact, getting rid of the hoses that run through there is called the throttle body bypass, and is very common. I've actually removed that little block in my wife's car. It's run fine ever since.

I think the IAC might be bad, though.

 

[silver93sho]

Ok, im going to try cleaning it first then ill go after a new one. Thx!

 

[sperold]

Maybe it helps in the cold weather?

 

[shoon]

Nope, as far as I know the reason they put that heater there was to warm the throttle body to prevent it from sticking in freezing temperatures. You should be fine without it.

Surging kinda sounds like a MAF problem, try cleaning and/or unplugging the MAF to see if the idle smooths out.

 

[silver93sho]

cleaning the IAC and MAF was on my list since the car has sat for 8 months not running at all. Ill try unplugging the MAF too, cant make things any worse!

 

[silver93sho]

Nope, as far as I know the reason they put that heater there was to warm the throttle body to prevent it from sticking in freezing temperatures. You should be fine without it.

I can see the logic if you are driving in sub 0 temps with cruise control on for long periods of time but thats about it!

 

[shoon]

I can see the logic if you are driving in sub 0 temps with cruise control on for long periods of time but thats about it!

That's the only plausible explanation I've heard for the purpose of that heater block... I'm no ford engineer though

Edit:
A quick google confirms it;
With the stock setup, antifreeze from the cooling system flows through a housing attached to the bottom of the throttle body. This heats the throttle body and the upper intake manifold, somewhat raising the temperature of the air being sucked into the engine. The only reason this is there is to prevent the TB from icing up during the winter in cold climates, but this has never been known to actually happen. I havn't had any problems since the bypass (been through 3 winters), and it gets pretty cold in Iowa. You probably won't notice much, if any extra power from this mod, but it will make the top of your engine much cooler, and make the removal of the TB in the future much easier.

http://www.v6z24.com/howto/heaterbypass


There must have been an issue at some point with tb's sticking, so they might have made it a standard feature to avoid risk of recalls.

 

[walser]

my car is running real rough it'll clean out for a while but then it will randomly start surging. rpms dont fluxuate to much but i can feel it when sitting in the car and is very easily heard, but if i unplug the MAF it smooths right out, MAF problem?

 

[hawkeye18]

my car is running real rough it'll clean out for a while but then it will randomly start surging. rpms dont fluxuate to much but i can feel it when sitting in the car and is very easily heard, but if i unplug the MAF it smooths right out, MAF problem?

Yup. If a problem goes away right when you unplug something, 99% of the time the problem is whatever you just unplugged.