[RESOLVED] I think im underboosting!

[2gangel90]

How everyone doing! I need some help please!
I think im underboosting the problem is that i have a 99 GST with a 16g turbo with a bfmi and a greddy bov stock internals! Im runing 14psi and im pretty sure every one knows what a car sound like at missfire well thats what it sounds like when i go from first to second gear and hold my boost at 14 right before i shift. I want to assume im not getting enough air and its causing me to under boost i dont know! If i don't make myself clear please let me know to try to explain better. I was reccomended to buy a safc2 to manage air flow but im not quite familiar with that yet. Thanks for your time!

 

[Mr PopUps]

Yea i cant really tell what youre trying to say. If youre holding the gas pedal down when you shift, youre hitting the rev limiter, not misfiring. Thats not really good to do, plus you can spin your clutch and shorten its life.

On a turbo car, unless you completely block the inlet, you cant 'not get enough air' and you cant 'underboost'. When you shift, its normal for the boost gauge, stock or aftermarket, to go to vacuum until youre accelerating again.

 

[booostedGSX]

Is the Greddy BOV re-circulated? If not, that can cause some funky stuff to happen.

 

[Mr PopUps]

Is the Greddy BOV re-circulated? If not, that can cause some funky stuff to happen.

True.

When i was looking for my DSM back in 98, i drove a 97 and was amazed how fast the rev limiter comes up without that throw you back in the seat yank of the 1G's tha ti was used from driving my friends car. Its still possible that in 'holding my boost at 14psi before i shift' she is hitting the limiter.

 

[2gangel90]

Yea i see what your saying but i dont mean missfire its just the sound that a missfire makes coming out of the exhaust at idle. Its sort of the same sound its making when i hold the gas pedal down to hold my boost and its coming out of the exhaust i dont loose any boost it just makes that sound repeatedly that worrys me.
Sorry yea the bov is recirculated.

 

[Colt4G63 also]

What RPM does the tach indicate when it makes this noise?

 

[Mr PopUps]

Yea i see what your saying but i dont mean missfire its just the sound that a missfire makes coming out of the exhaust at idle. Its sort of the same sound its making when i hold the gas pedal down to hold my boost and its coming out of the exhaust i dont loose any boost it just makes that sound repeatedly that worrys me.
Sorry yea the bov is recirculated.

Are you shifting with your foot down?

What RPM does the tach indicate when it makes this noise?

Yea, thats a good one

 

[2gangel90]

I dont know if this helps but its worth a try. Its kind of a discription of the sound in words!
Rmmm then i hold my boost (holding gas pedal) then pough pough pough at boost limit, then release gas and shift.

 

[Mr PopUps]

I dont know if this helps but its worth a try. Its kind of a discription of the sound in words!
Rmmm then i hold my boost (holding gas pedal) then pough pough pough at boost limit, then release gas and shift.

So, youre IN gear or not?

Or: rmmmmm (in 1st gear) pough pough pough (STILL in 1st gear), let off gas (STILL in 1st gear, but pressing in the clutch), SHIFT, rmmmmm in 2nd gear.....

What size injectors and FP are you running also? You left that out of the first post.

 

[2gangel90]

No my foot is compleatly off the gas.
I realease the gas apply the clutch bring down to second gear once in gear apply the gas and level after that. Im not sure i havent payed attention to the rpm's but my guess is between 4 and 5.

 

[2gangel90]

Thats exactly right!
When i bought the car it was stock it only had a sway bar, stock turbo and set up, and a thermal exhaust. I bought it off a older women she claimed it was her sons that had gone into the army and was sent to iraq. So my guess is stock injectors and fuel pump not really sure.

 

[oVaBoost]

might have a boost leak or your safc2 isnt controlling air/fuel mixture right and if you have stock injectors its kinda worthless

 

[Boosted SuFi]

If you have a larger exhaust over stock and no cat, with the higher boost level and the tweak on the SAFC (I think I read something about one), you may just be hearing exhaust "gargle". If so, it's not that big a deal, my car does it and its fine.

 

[2gangel90]

I see but thats the thing i don't have the safc2 yet i was told that would fix my problem.
But i wanted to be sure it would help before i bought or getting the injectors and the fp first.

 

[phill]

I didn't think miss-fires made a noise? Isn't that why its called a miss-fire, it doesn't ignite? so no noise right?

Do you mean it BACK-fires? It could be the gurgle from the exhaust the above post mentioned, mine does that too.

 

[Colt4G63 also]

Ok then it's not the rev limiter . I had to ask sorry. Is it just a sound, or do you feel a loss of power? My car was making a sort of fluttering or pulsing noise when my boost controller decided to go on strike. I think my wastegate was fluttering open and closed. I have an aftermarket boost gauge, so my second clue that something wasn't right was when I noticed that I was pushing over 20 psi.

 

[2gangel90]

I see what your saying but its two different noises we are talking about. I see what you mean tough dont get me wrong but for example whe you turn your car on it struggles to stay on not idleing right making a noise thats sounds like pough pough pough out of the exhaust. Well if you can kind of picture what im saying but know just that same noise nothing to do with the missfire concept just happening how i explained earlier.

 

[phill]

Are you throwing any codes? A missfire should make the CEL blink a few times if I'm not mistaken

 

[2gangel90]

No none at all thats why im having trouble finding where the problem lies. Im going to try runing a boost leak test see if that leads me any where. Wierd huh!

 

[Mr PopUps]

Im thinking melted pistons..... might be running too lean. I hope im wrong on that!

 

[phill]

if you're not throwing any codes I'm 99% sure its not a misfire. you're car takes into account how much air is being put into your engine and adjusts fuel accordingly. the only thing I can think of is a boost leak after the MAF. But idk the 4g63 too well, I like my 420a

 

[Colt4G63 also]

Do you have an aftermarket boost gauge? If it's making pough pough pough noise, but it doesn't feel like a missfire, how do you know it's not the wastegate or BOV fluttering. A missfire would give you a dramatic loss of power, a fluttering wastegate might just give you a pough pough pough noise under full boost. As long as you have the fuel to support the unexpected boost, you could be knocking and pulling timing, and not even know it. Stock boost gauges just give an estimated reading, and can easily be wrong. If you have a boost leak. they will read higher than true, because it's extrapolated based on how much air is coming in.

I'm not saying not to boost leak test, just that when you do, check that your wastegate arm opens at the correct pressure.

 

[caseyk]

I hope this helps you with your problem. When I first bought my eclipse, it would have like a misfire type thing going on when your WOT. It didn't happen when I was driving normal, Only when I was full throttle. It would act like a misfire throughout the rpms. I found out that I just had to re-gap my spark plugs. It's kind of hard to tell whats your problem.

 

[mrTalonAWD95]

youre running a vented bov. does your car die when you stop shortly after you ream on it? check to see if your bov is leaking.

 

[2gangel90]

I hope this helps you with your problem. When I first bought my eclipse, it would have like a misfire type thing going on when your WOT. It didn't happen when I was driving normal, Only when I was full throttle. It would act like a misfire throughout the rpms. I found out that I just had to re-gap my spark plugs. It's kind of hard to tell whats your problem.

Problem Solved guys. This was actually my fault i started thinking about what member Caseyk said in his earlier post and something was just not making sence. I had changed my spark plugs last tuesday but heres the problem i bought platinum denso plugs because that is what the employee at autozone suggested which also said were already pre gapped so i listnen to him and as of then is when i started having this prob so today i took the plugs out and they were burnt out i went to checkers and got their ngk iridium plugs and problem solved. I want to thank everyone for their suggestion and for taking their time to help me! Greatly appreciated. DONT USE PLATINUM PLUGS!