MitsuJDM

iTrader: (6)

It's insanely cold out right now and supposed to snow, so I take my car over to a friends house and hang out for a little. On the drive there, I did a hard pull up through the gears and noticed just a slight lack of power. The car usually spikes at 25psi and settles at 22psi in lower gears but in higher gears will hold 24psi. It was spiking 21psi and dropping to 19 or so. So of course, like most people by now are thinking... I better do a boost leak test.

Here's the tricky part. I did a hard pull up through third and forth gear. If starting from 1st or 2nd gear and going up through the gears, 4th gear will do the same as the lower gears (spikes 21psi, drop to 19psi)... but when rolling in 4th gear and I go WOT, it'll spike 26psi and hold 24psi.. like it should I understand the engine's under a greater load there for will hold boost better. But why was it not doing this (italics) earlier (in the bold)?

So I was assuming boost leak. Most of you will recommend a boost leak check. No big deal, but I was thinking it may be doing something else here, maybe the air temp, ECU doing something funky due to air intake temps, or wastegate doing something weird. I took a quick look but to see if I could see any visable leaks like vac. lines popping off as that's happened in the past, but didn't see anything. It's 24 degrees right now with 20mph winds... I don't feel like looking in detail

sparky

iTrader: (1)

It is so insanely much colder today than when your car was originally tuned that you probably would need a retune. Are you able to do any comparative AFR logs? It's not a boost leak. It is just the way that the ambient temp drop has impacted your AFR's. The colder air means more densely packed oxygen molecules.

MitsuJDM

iTrader: (6)

I was thinking colder air made boost pressure rise. or else I would have just brushed this off as no problem. But I've been wrong before.

Unfortunately, I'm lame and don't have a wideband or any way of logging.

MitsuJDM

iTrader: (6)

Sooo yeah. I was just a boost leak. I check it today. The cooling fan made it's way through the OEM IC pipe coupler I guess when it expands under boost. I can see a black mark on the fan and can feel a hole through the coupler. I used a smoke machine to find it.

sparky

iTrader: (1)

Do you have the stock thickness radiator? Just curious. Glad you found the problem though. I was wrong about it not being a boost leak then, duh!

boosted91t

iTrader: (65)

Had a similar problem with mine when I had the stock uicp, caught it before it wore through totally. Atleast its an easy fix

MitsuJDM

iTrader: (6)

Well the problem is, the bolt to the bracket that bolts the IC piping to the chassis of the car is missing, letting the UICP sit a little loose. Then under boost, the rubber couplers expand and it rubs the cooling fan. I need to replace that bolt.

I didn't see the need to order an aftermarket UICP as they give very little gains anyway. I just ordered the OEM coupler as a replacement. It's $60 shipped , but better than $300+ for a pretty UICP that doesn't do anything. I don't care for a pretty engine bay, just clean and to the point. The car is a 2005 VIII with a IX turbo. I'll eventually do a CBRD BBK upgrade, but even then, the OEM UICP shouldn't limit the car. So I didn't feel a aftermarket UICP was a justified purchase.

I didn't think it was a boost leak either. But I figured I'd check just to cross it off the list. I almost didn't find anything, but right when I was about to confirm it wasn't a leak, I found it. I was SOOO happy Easy fix.

Now I need to find the coolant leak causing air pockets in my cooling system, causing my temp gauge to fluctuate These damn cars..... And then the decel noise from the input shaft...ugh

cij911

iTrader: (14)

Your boost issue was obvious - you don't need to retune a car for cold weather on pump gas (sparky - tisk tisk ). I'm glad you checked for boost leaks (and found it).

Unless you are noticing your coolant level decrease, I'm sure you are looking for the wrong solution here as well ...

What are the symptoms with your temperature gauge ? Did you recently change your coolant and not let it purge properly ?

MitsuJDM

iTrader: (6)

I can smell a coolant leak. It's very, VERY slow. Every now and then I'll add some coolant and bleed the system and it'll go away for awhile. The car has been taking awhile to warm up, but it'll usually reach operating temp and stay there. Then, I know to re-bleed the system when it starts fluctuating. It'll go up and down from operating temp, to about the 1/4 way mark, to completely cold on the highway. The getting off the highway, it'll slowly warm back up and fluctuate depending on speed or throttle.

I've already replace the T-stat as the first, easy fix. Didn't solve it. I've thought about it being a head gasket, but I'm not too sure. It doesn't have any head gasket symptoms.

So I was just set on there being a leak, allowing air pockets in the system.

heaveho

Change the rad cap. Probably not that, but cheap to try.

Also, if you can smell coolant in the car, check the heater matrix and associated pipework.

Good luck finding a cure.

Ginglingston11

iTrader: (8)

good idea....way tooo many times over looked

heaveho

I'm a bright guy, but I hide it well!