Hey guys, so like the title says, not sure but I think I have a boost leak. I was driving home one day and as I hit a red light, all of a sudden my idle dropped and I stalled the car. After restarting the car, I noticed my car wouldn't keep idle so I had to continuously gas it at every stop light until I got home.

When I got home, I tried trouble shooting but haven't come up with anything amazing. The car runs fine without MAF but won't hit past 3k rpm (don't plan to drive like that but was testing to see if maybe the MAF was faulty). I'm getting some white smoke at idle and black smoke when I gas. I feel like it's a vacuum leak but I have no idea where I could be leaking from. I was going through my engine bay and found this hose on the fire wall:



not sure what it's for so I thought I'd ask here.

Aside from that I checked all the piping and everything seems perfectly fine. My boost gauge is reading -10 though so I'm fairly certain there's a leak somewhere. At this point the car doesn't idle and it dies everytime I start it.

Please help!!

 

That hose is for the A/C system. It drains condensation from the system inside the cabin. I would check the vacuum lines around your injectors. The EGR solenoid vacuum lines pop off easily under boost and are easily overlooked. I would also check to make sure your injectors are seated correctly inside their insulators in your intake manifold. I've popped injectors out of place under boost due to fuel rail bolts that backed themselves out over time. But you definitely have a vacuum leak somewhere.

The white smoke at idle might be an indication of a bad head gasket. Check in your oil to see if you have coolant and check in your coolant to see if you have oil or can smell exhaust in the coolant overflow.

 

idle vacuum is 18-22 hg in. you have a vacuum leak somewhere dont forget the throttle body shaft seals

 

awesome thanks a lot for your input guys! i'll check those out tomorrow morning!

and yes, normally idle is -22 for me as well. just strange because I wasn't even boosting when it happened. Didn't know the injectors could have a leak. is there any test? or am I just listening for a hissing noise?

 

i had this problem with my car also, but it was because of my piggy, one pin was disconnected, and the behavior of my car was exactly the same. but that was my problem.

 

hey guys just letting you know that i found the leak -_-" my dp bolts blew off so i just replaced them, hahaha thanks for the help!

 

your dp bolts made it do that? i have mine still tho, so i get to keep looking for some other leak. this is awesome..

 

mine turned out to be the throttle body idle speed sensor. its the black thing mounted below the inlet in the throttle body that the uicp goes into. its also known at the stepper motor or idle motor. just figured i would share this info for anybody else that has this problem.

 

i dont know about in utah, but here in America we call that an idle air control valve(iac valve)... lol

 

I've ran into these type symptoms before...once it was the TPS plug came slightly unplugged losing contact and another time was an ECM plug not fully seated

 

I used to work for mits. go look in their computer and see what they call it....

oh ya i did, throttle body idle control sensor

 

if you look at it its obviously not a valve, its pretty aparent its a sensor

 

Acually it is a valve...aka IACV....it regulates the amount of air flow that bypasses the throttle body when closed...in turn regulating the idle....a sensor only sends information it is reading to the ECM.....The IACV also helps keep the engine idling based off different loads such as when the A/C is turned on...the engine will just about stall if the IACV didn't activate in which more air bypasses the TB blade in turn raising the idle.

 

i sir, also use to work at a mitsubishi dealership and i know that 75% of the people working there know didly squat about cars. regardless of what they "call it" , its a IACV(idle air control valve). mine is in the process of going out on me, well it has been for the last two years, so it throws my CEL every few hundred miles. when you pull up the code is says faulty idle air control valve.

also this has never caused my car to stall, just fluctuate rpm at idle from around 500 to 1000rpm. also it only does this on hot days or very long drives.

perfect definition if you have ever taken one apart, which i have several times, its very clear that it is a valve. theres a spring and everything..lol

 

yeah put your turbo in a bucket of water connected to a vacumm and if its not making bubbles you have a leak sir lol JK