newbie question/stock boost gauge

[khrispy]

The stock boost gauge on my 1G eclipse does't work correctly: it either reads at the extreme bottom, or shoots up past the top past about 3000 RPM. Is this a problem with the gauge (ECU?) or could it be an actual boost problem? I just bought the car three days ago and I'm not all that familiar with turbos yet. When should the boost kick in and what should it sound/feel like in normal operation?

Thanks for your patience

-Chris

 

[talon1987]

The stock boost gauge is pretty much crap ... it doesnt judge the amount of boost you are really running ...it judges that amount of air that goes through your mas ... so pick up a aftermarket boost gauge there alot more accurate

 

[oldman]

The stock boost gauge on my 1G eclipse does't work correctly: it either reads at the extreme bottom, or shoots up past the top past about 3000 RPM. Is this a problem with the gauge (ECU?) or could it be an actual boost problem? I just bought the car three days ago and I'm not all that familiar with turbos yet. When should the boost kick in and what should it sound/feel like in normal operation?

Thanks for your patience

-Chris

More reason to get a real boost gauge immediately so you can figure out what is causing it, worst beening overboosting.

 

[Tsi_User]

what PSI does it say it's reading at when it spikes? These guys are right though, the stock boost gauge is just a computer approximation and your first mod should be getting a new one. As soon as you start modding the car (even minor mods) it's gonna throw the stock gauge off.

 

[khrispy]

The needle flips all the way up till it hits the turbo symbol on the gauge (past the numbers). The previous owner removed the cowling over the intake filter after replacing it with a K&N, could that be messing up the airflow sensor?

what PSI does it say it's reading at when it spikes? These guys are right though, the stock boost gauge is just a computer approximation and your first mod should be getting a new one. As soon as you start modding the car (even minor mods) it's gonna throw the stock gauge off.

 

[khrispy]

about what RPM should boost start to kick in?

 

[Tsi_User]

when you say "cowling" are you talking about the air can that the K&N sits in? If so, not that shouln't be the problem.

Af far as when boost kicks in, i'm sad to say that I don't know because i haven't driven mine in over 8 months and I don't remember

what I would do is buy a boost gauge/pod and screw the stock boost gauge. If the needle spiking up all the time gets annoying do what I did and cover it up with some electrical tape.

 

[DSM Loki]

the turbo spools about 3000 rpm if you're on the stock 14b

 

[khrispy]

Good to know, thanks. I've noticed the engine also makes a kind of growling, deep vibration noise around 3000 instead of the normal turbo whine if I'm not giving it more than 1/2- WOT. Is that normal?

 

[khrispy]

From the 1000 already asked questions website:

The stock 'boost gauge' actually reads out an educated guess from the ECU as to what the boost should be.# The guess is based on RPM and airflow into the engine, both of which the computer does monitor for other reasons.

...so is my MAF messed up?

 

[oldman]

It's time to stop guessing and do some trouble shooting. Install that boost gauge now and post back with some real boost numbers and we'll help you figure this out, can't really do anything without a boost gauge. In the mean time, DO NOT WOT except for test runs after you install the gauge.

 

[khrispy]

Sorry, should have mentioned- I installed an aftermarket boost gauge last week, I'm only getting about 5 psi boost at WOT and 7000 RPM, so there's a huge leak somewhere...

 

[oldman]

Sorry, should have mentioned- I installed an aftermarket boost gauge last week, I'm only getting about 5 psi boost at WOT and 7000 RPM, so there's a huge leak somewhere...

Can be a lot of things boost leak included but not limited to. This what I would do in sequence.

1. Make sure the actuator arm is still connected to the wastegate lever.

2. Check and make sure there are no huge exhaust leaks before o2 housing.

3. Perform a REAL boost leak test, fix all leaks until system able to hold 20psi for a reasonable amount of time, like 30 seconds. This is important. http://www.vfaq.com/mods/ICtester.html

4. Disconnect the hose to the actuator (disabling the actuator) and test run. If problem persists, turbo is the problem. If you get all out boost, I assume you have the common sense to let off at about 20psi, you have a actuator that opens prematurely.

Good luck.

 

[khrispy]

Wastegate- check
Exhaust leaks- had a cracked manifold, but got that replaced
Boost leak test- gotta get a hold of the parts and pressurized air... and find time to do it
Disable actuator test- Hmm, maybe I'll try that when I get home today

I read that the stock boost gauge needle flopping around and rough idle (which I also have) can be a symptom of a vacuum leak- got any suggestions on how to pinpoint it?

Thanks for your help

Can be a lot of things boost leak included but not limited to. This what I would do in sequence.

1. Make sure the actuator arm is still connected to the wastegate lever.

2. Check and make sure there are no huge exhaust leaks before o2 housing.

3. Perform a REAL boost leak test, fix all leaks until system able to hold 20psi for a reasonable amount of time, like 30 seconds. This is important. http://www.vfaq.com/mods/ICtester.html

4. Disconnect the hose to the actuator (disabling the actuator) and test run. If problem persists, turbo is the problem. If you get all out boost, I assume you have the common sense to let off at about 20psi, you have a actuator that opens prematurely.

Good luck.

 

[oldman]

Boost leak test- gotta get a hold of the parts and pressurized air... and find time to do it
Disable actuator test- Hmm, maybe I'll try that when I get home today

There's a reason I stated the leak test first, if problem persists after you remove the hose, you still don't know if problem is leak or turbo. Doing the leak test first can also ensure you don't over boost the turbo accidentally.

I read that the stock boost gauge needle flopping around and rough idle (which I also have) can be a symptom of a vacuum leak- got any suggestions on how to pinpoint it?

boost leak test does wonders.