nos_fx

iTrader: (1)

So this long weekend I had time to play with the car, one of the parts that I had that i put on was a TB that had the TB mod done to it. The secondary plates were removed and it was bored out a little...I know it works because it came from a race car that used it for a long time, but now runs ITB's with a bridge port...but both cars are S4 NA, so it should be ok.

Anyways, I installed it yesterday and now whenever I start it up it revs up to 5000rpm or so and stays there...also I noticed moisture coming out the exhaust...looks, and feels like coolant.

I've been looking at the car, looking at ALLDATA and reading all the posts I could find about the air bypass solenoid valve, but can't get it figured out. There is a hose that goes to the water pump that has coolant in it, but why do they want coolant going into the intake I don't get it...and what is causeing the rpm to go so high?

any thoughts?

thanks a million!!!

-Kyle

nos_fx

iTrader: (1)

here are some pics to help show what I'm talking about.



see this hose comes from the water pump and has coolant in it.





this is just showing that the secondary plates were removed.

I transferd this over from my original TB, but as the next pic shows I caped off the vacume hose that goes to the secondary plates...this is really the only thing different between the two tb's



should i maybe transfer this over to the new TB but not have it do anything, other then just somewhere to run the vac line I caped....?

and this is just an extra shot of the engine bay...

nvrdone

adjust the idle.

nos_fx

iTrader: (1)

I did try to adjust the idle screw on the top of the tb, I also tried the dash pot, thinking that it was holing it open a little, and I also tried adjusting the TPS, none of these helped, or changed it in any way.

nos_fx

iTrader: (1)

should I try unpluging and caping the lines for the BAC and see what that does? Would this likely be the direction I should go?

nvrdone

The BAC helps idle, unpluging will prolly make it worse.

MidnightOwl

Is the throttle cable stuck? Unplug the throttle cable and see if it does it.

hhn2002

remove your bac. see if its leaking any coolant into the intake. sounds like it might be a large vac leak. having rpms that high at a cold start up is bad for your engine. get a garden hose and spray directly at your intake for a while getting it from as many directions as possible with ur engine on then see if ur idle improves. if it does than its a vac leak. u can unplug ur bac safely and run it that way for a while.

ramses666

iTrader: (1)

I would say to ditch the coolant lines to the throttle body and BAC. Remove all the thermowax and fast idle stuff if for some stupid reason it's all still there. you said the TB was modded? So this was already done?...

Don't remove the BAC valve. You can diconnect the coolant lines that went to it. Or maybe yours is gone too! BAC helps the motor increase idle when the brake is pressed, or the AC is running or your turning the steering wheel. Anything that increases the load the BAC lets air in.

Sounds like something in the linkage is stuck. Or maybe really leaky injectors.

Ramses666

nos_fx

iTrader: (1)

Thank you all for taking time to answer...

The throttle cable and all linkages are ok, I am able to open the throtle all the way and it closes properly with the srping tension. leaky injectors don't make sence either, I drove the car eariler that day, and it ran great. I think I'll try unpluging the BAC and disconecting the coolant lines tomorrow.

Yes the TB was already modiffied when I bought it. It had the TB mod done, and then ran a few seasons on a race car before I picked it up. So I know it should work...

Thanks again for all your help, I'll post results whenI have them.

-Kyle

hhn2002

with such a high idle it could only be a vacuum leak or stuck throttle plates. u confirmed it ur self that it wasnt a stuck plate. leaky injectors would just make it run rich but with throttle plates closed it would be too starved of air to increase idle by that much. its got to be a vac leak plain and simple. make sure also that you've got no open vacuum nipples that u may have left. again try the garden hose test or starter fluid spray test. you'll find ur culprit. GL

Icemark

The BAC can't leak coolant into the intake. If you look at the BAC design, the coolant line is a small alum tube bolted onto the back of the BAC. BTW, the alum tube is isolated by the BAC and BAC gasket from actually being connected to the intake manifold. You can unbolt the coolant line from the BAC if you so desired, as again, it is not part of the BAC, but rather part of the cooling system.

The only way that coolant can be dumped through there would be if the alum coolant tube was drilled out and the BAC valve was rotted out in exactly the same spot, and that spot was within the last 1/2 inch of the BAC valve.

So if you have coolant in the engine/exhaust, it is getting in there from somewhere else (probably a blown coolant seal).

hhn2002

woah i could have sworn they shared passageways jk
yea i was just throwing out ideas. i wasnt sure at all but hey it couldnt hurt.thanks icemark for sharing ur godly fc wisdom upon my unlearned'd newbness.

Aaron Cake

iTrader: (1)

All that will accomplish is making the car a real pain to drive in the cold weather. The thermowax, fast idle cam and related will never cause a 5K "idle". Removal of this stuff is totally pointless and has only downsids.

The original posters problem is likely due to a large vacuum leak or a physically struck throttle linkage.

Leaky injectors would flood the engine with fuel, causing a low and unsteady idle.

nos_fx

iTrader: (1)

I put the stock TB back on, and it seems to run much better...its not idleing at 5000rpm...but still has coolant coming out of the exhaust...where could this be coming from? All I did was change the TB, it never burned any coolant before, The engine only has 76,000km on it...what could possibally changed when I changed the TB? the only related part that has coolant in it, is the BAC...so for diagnoses should I cap off all lines for coolant for the BAC and run the engine to see if that makes it stop?

-Kyle

Icemark

Did you not read my post in this thread?

What didn't you understand in it?

THERE IS NO POSSIBLE WAY THAT COOLANT CAN GET FROM THE BAC INTO THE INTAKE OF THE ENGINE.

SpikeDerailed

iTrader: (7)

What does this "coolant" look like coming out of the exhaust now? A decently heavy white smoke, or physical water? Have a maple syrup smell? The exhaust system will have condensation in it till it heats up and causes all of it to evaporate.

nos_fx

iTrader: (1)

Yes, it is white smoke with a sweet kind of smell to it.

-Kyle

23Racer

Kyle, the throttle body came off a BP and had the idle settings changed. The physical adjuster is on the bottom of the throttle body and is a screw with a jam nut. It is almost impossible to adjust with the throttle body on the car. You will need to set it back to stock settings to get a reasonable idle. I think that somebody here can get the drill gauge setting for you. The other thing I would look into is the freeplay in the throttle cable. If it is too tight then the cable will prevent the throttle plates from closing.

I hate to agree with everybody on your smoke and sweet smelling exhaust, but it sounds like a coolant seal. I would check your coolant levels to see if you are loosing any. It sounds like you have a seal going away and they can pop without warning. That is a pain as your car is gorgeous and I hate to see you having problems.

Let me know if I can help in any other way.
Eric