what could be wrong with my gst?

[boostingsx98]

I currently have a 95 gst. Mods are 16g, full 3inch exhaust,fmic, walbro 255, ported and polished head. Boostin at 11-12psi. So here is the story. Yesterday i was driving my gst with my buddy and everything was fine. This morning i wake up to turn the car on and its idling a bit rough. So i let it warm up things got a little bit better. I started to drive it and i could go passed 3 thousand rpm because it would bog. So i check for a blown coupler or boost leak but i couldnt find one.. another weird thing i noticed is when i gased it in neutral i would build boost up to ten pounds! how is that possible?? Can anybody give me an idea or clue on what could be wrong with my gst?

 

[gregalmighty]

Sounds like you have a BAD boost leak. Just because nothing is visibly wrong doesn't mean there is nothing wrong. Make a boost leak tester: http://www.dsmtuners.com/forums/new...se-troubleshoot-boost-leak-tester-merged.html

Pressurize the system to 20-25 psi, have a buddy watch the boost gauge to see if and how fast it drops. Listen and use soapy water to find it. Could be in the injector seals, intake manifold gasket, throttle body, bov, any of the couplers, or even your wastegate malfunctioning.

I don't see anything about an aftermarket boost gauge in your mods but I am assuming you have one.

 

[boostingsx98]

yes i have an after market boost gauge..

 

[gofer]

i just want to say that your mods make no sense to me whatsoever...

-youve got a walbro 255 but you have no afpr or injectors.

-your running a 16g at 12psi.

-you have a fmic running 12psi.

alright, back on the topic of bogging. watch your boost gauge when its bogging, whats it doing exactly? do a quick scope of the engine bay... MAF connected, uicp, licp, etc. etc. for obvious boost leaks. im saying if your idling rough and its bogging hard at 3k then your over running your stock fpr with that 255 making you run rich.

 

[sparco431]

for sure a boost leak

 

[boostingsx98]

Well the weird thing is the blow off valve goes of at 3 thousand as loud as it does when its at 5 to 6 thousand and i build ten pounds of boost in neutral when just reving it......

 

[gsxeclipse97]

I would check maf also then go to boost leak test. check intercooler to make sure there are no cracks and what not.

 

[92ts1]

How much boost are you building around 3k? Sounds to me like it's getting put under and extreme load. Have you checked your timing? Both belt and ignition?

 

[boostingsx98]

Yes timing and ignition are fine. Iv been driving my gst for the past 2 months and it has not given me any problems. This just suddenly happened and i have no idea what it could be.....

 

[92ts1]

So have you looked to see how much boost you have at 3k?

 

[boostingsx98]

yes it shoots up to ten pounds in idle.

 

[bsm4590]

Is your mass airflow sensor next to the air filter unplugged?

 

[boostingsx98]

no everything is plugged in.

 

[eclipsemustang]

my car did this when my SAFCII got unplugged

 

[boostingsx98]

i dnt have a safcII....

 

[90T5I]

my car is doing the same thing. does it smell rich? try running it then unhooking the maf. it should run a bit smoother with it unhooked. after u unhook it the computer goes to a base setting. if it runs a lil smoother then the maf is your problem

 

[All_Boost16G]

Couldn't the wally 255 pump overran the regulator finally and some its just super rich causing it to bog, kinda of like a boost leak.

 

[motomattxxx]

yes it shoots up to ten pounds in idle.

Are you sure that you dont have 10 in of VACUUM instead?

 

[Talon64]

When your car is running. Tap the top of the maf. If it rpms goes up or down you know what it is. Would be a good idea to get a fuel pressure regulator.

 

[boostingsx98]

well i was tryin to get the gst into my garage and the rpm guage started to bounce up and down to 9k and back but engine sounded normal like it was just idling. Then it shut off and now i cant start it! i dnt know what to do?? any ideas?

 

[gofer]

9k? our cars can't even rev that high! it would be a lot easier to help you fix your car if you give everyone information we can use. the stuff your telling us doesn't make sense man...

 

[boostingsx98]

yea i know it doesnt make sence, thats y i dnt no whats goin on....

 

[talon187]

i cant understand what hes trying to say

 

[motomattxxx]

Loose battery cable maybe or an alternator that isn't charging possibly.

 

[boostingsx98]

the rpm gauge bounces up and down but the car sounds like its idling fine.