Does coolant run through the IAC?

[aheroicrevolt]

I installed a FFIM with a IAC flange on it, but blocked it off.
My car is surging very badly when starting. It'll rev to about 1800rpms and then kill itself until it drops to about 1000rpms and it will turn itself back on, then climb back to 1800 and do it over and over and over. This happens rather quickly it is not a slow increase in rpm, pretty rapid.
So ide like to put my IAC back on, but I am not sure what all the fittings go to.
2 small fittings on the underside- I thought one hose might come off the coolant tube under the Intake manifold and flow into the IAC then the other flows out of the IAC to the fitting on the stock throttle body and then out the TB back down to the coolant tube? Why would they pump coolant through the IAC? Am I actually right in that thought?
1 large fitting that bends around towards the "top" No idea what this tube/fitting should connect too on a FFIM that's running a q45 throttlebody.....

my knowledge is limited :nono:
my search is limited. :nono:
But I have tried for a couple hours. Just no definitive answer :nono:

 

[hvyman]

Yes the 2 small ones are coolant. its so when in cols temps the engine will warm up and not freeze or stick.

If your on stock ecu you need to run the big one to the intake before the turbo.


when searching try searching with basic words and more than 3 letters. if 3 letters use * at the end. The search is great here and there is lots of good stuff to almost 10 years ago.

 

[aheroicrevolt]

Yes the 2 small ones are coolant. its so when in cols temps the engine will warm up and not freeze or stick.

If your on stock ecu you need to run the big one to the intake before the turbo.

SO run a rubber hose from the intake tube- just after the MAF housing- but before the turbo inlet correct?

My car is a summer car. In Michigan.....you cant drive the Supra from November to March lol so I can leave the coolant passages open I presume

 

[IndigoMKII]

Check your tps and make sure your throttle body isn't sticking open.

If your throttle body is sticking open and the ecu is seeing the IDL contact as grounded, it'll cut fuel above XXXX rpm then turn the fuel back on at XXXX rpm rinse and repeat.

 

[emericaskater285]

you can also just put the iac valve back on without the coolant hoses ran to it. A good friend of mines car hasn't had the coolant lines on it for around 5 years now and is running great, no issues what so ever with it. I have mine deleted from my white car that has a ffim, but the black car still has it on it, but I bypassed the coolant lines on it doesn't run any different.

 

[hvyman]

Bypassing the coolant lines wont effect how it runs. Its more of preventive design and pretty much every engine manufactuer does it. Some people do drive there cars when its below freezing and thats when it will be useful as anti freeze doesnt freeze so it will help with your throttle not stick because its frozen.

 

[aheroicrevolt]

Check your tps and make sure your throttle body isn't sticking open.

If your throttle body is sticking open and the ecu is seeing the IDL contact as grounded, it'll cut fuel above XXXX rpm then turn the fuel back on at XXXX rpm rinse and repeat.

Thanks! This is exactly what I wanted, some ideas of what else it could be instead of the IAC lol.
Ill check into this right after mounting the IAC if the car is still surging. I currently have the idle screw holding it open a tiny tiny bit so air can still flow to engine.
Should I adjust the idle screw all the way out even though there is not an air bypass like stock TB? Wouldn't it be completely sealed then? Thus cutting off the air flow completely to the engine?
This is the Throttle body I am running>>> http://www.rc-turbo.com/images/dyn/fsi/TOYOTA-TB-(WM).jpg

 

[hvyman]

If you adjust the idle screw you need to adjust the tps to match.

 

[aheroicrevolt]

I found this by searching. :biglaugh:

Does this really work for adjusting the tps? Because I do have code 5-1 right now...

Simple and plain the easiest way to setup the TPS:

1. install the TPS with the screws loose enough to rotate the TPS
2. Bridge the Diagnosis terminals like you'd check for codes
3. Rotate the TPS in very small increments until code 5-1 stops flashing (if it is at all)
4. tighten screws

 

[IndigoMKII]

You want the throttle body to completely close. The reason for this is because you're still using an idle speed control valve(ISCV) and it'll flow enough air to keep the engine idling. With the throttle body cracked open slightly and still running an ISCV, it's much easier to close the throttle body fully and let the ISCV do what it was designed to do.

http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&P=125 this is what you're seeing correct? 1800-1200 rinse and repeat.

 

[aheroicrevolt]

That is exactly what is happening!! 1,600 it shuts off and picks back up about 1000-1200. Thanks Indigo!
So the fix is>>>

1- to hook up the IAC/ISCV module
2-close the throttle body completely
3-calibrate the TPS by slightly moving it back and forth while jumper wires are in until the 5-1 goes off the dash?

I do not have an Ohm reader, so the loosen and twist method would work awesome for me!

 

[3p141592654]

By the way, the IAC coolant helps prevent icing in high humidity conditions even when ambient is above freezing (see Joule–Thomson effect).

 

[jony89]

Any pics of your ffim setup?

 

[IndigoMKII]

No problem, keep us updated after you get it fixed.

 

[aheroicrevolt]

So its not code 51. Its 52 which is knock sensor. I have to drain the gas and get new stuff in there.
Cant start the car now because I just learned that I have 0 oil pressure. So the revs will have to wait.

I shimmed the pump when installing, what ciuld be wrong? Now I have to undo the driveshaft, take the transmount off, and speedo cable, undo a bunch of wiring, and let the trans tilt downwards. Does the whole engine need to come up 8inches or just the front like its tilted?
ugH what a headache

 

[super51fan]

drop down the sub frame.

 

[Bmettie]

^This!!!!!

Get one of these, easy as pie.

 

[jetjock]

Crack me up...

 

[Nick M]

Crack me up...

Would you like some pie?