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Discussion Starter #1
this is the continuation of an earlier post but I would really appreaciate it if you performance gurus would help me out here and tell me what to check and what to look for. I have the ATR and HKS evc ez, 440cc injectors, fuel pump, afc2, dual friction centerforce clutch...I am just wondering if there is a sensor that's burned causing my car to feel like it's out of breath...after 4500rpm even with turbos at 15psi the cars feels like a n/a hehehe sort of...I have a 96. I thought that my cluctch was slipping but I realized that this was not the case cuz I spoke to Vr-4Tissimo and he said that his 1st gear at 7000rpm hits 41mph...which is the same as mine...so it's gotta be something with the engine management...a sensor? or is it that the wastegates are not calibrated or are letting to much exhaust escape? also, when I bought this car in 97 (stock). I took it to the dealer and had them look at the clutch cuz it was grinding on 2nd...ok I get the car back and the car was not as fast as I initially felt. then, I changed the motor oil and then took it for a spin. I step on the pedal and I saw the stock boost gauge hit 14psi and did feel like the turbos where kicking...but as you know the stock gauge is inaccurate but then suddenly I let go off the throtle and then I just step on it half way just so that the turbos spool up to 14psi (turbos already whistleling)when all of the sudden I hear a louder wistle (I did not move my right foot--it was in the same position)..then I feel the car THRUST forward!!! Real fast!!!! My brother was on the car and he too was scared...I think he was going to pi on his pants...
Anywayz, the car felt like it breathed so well and the engine was doing everything so effortlessly...but now even with the boost controller set at 15psi...the car feels like it's out of breath...and never felt that THRUSTING feeling anymore!!
I heard that somebody on the msgboard said that these cars are known to have problems with the wastegates or something related...PLEASE Help...I've been driving my car like this for the past 2 years! Brian or Roger or anybody who is adept in the subject


p.s. please look at my earlier post (boost dropping to 10psi at 5000rpm) for more info...thanks!

[This message has been edited by fastboy (edited December 08, 1999).]
 

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does the y-pipe gasket going bad cause decreased performance? mine got stuck somehow in the intake manifold and the rpms got increased all by themselves up to redline because of that. I took off the y-pipe and replaced (the same) gasket and that stopped that problem. There was a crack in part of the gasket. Would this cause decreased performance, leaking boost?
 

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Sorry I wasn't able to respond to this earlier(I work late shift sometimes) but time is better now. 1st I'm going to state that I don't have as much experience as Brian or Roger in this area yet, so bear with my troubleshooting..

From my understanding of it, the air is calculated in the MAS and if it is getting lost before it reaches the throttle body air intake, it can cause your car to run rich and probably even sluggish, which could be why you feel the lose of power more then just the normal 9b turbos not being able to hold 15 PSI boost to redline, but then wouldn't it run sluggish all the time..? although, the leak could be only apparent under heavy pressure. It's hard to diagnose through end users description that's for sure! I can only hope these ideas we give you help you look in the right areas and solve the problem. Try checking for leaks.

BTW,

When did this become noticeable?

Did you recently change anything, then notice this..?

Do you have a BOV?

What kind of exhaust do you have, stock..?

Mario

[This message has been edited by VR-4 Tissimo (edited December 09, 1999).]
 

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As stated in the other thread I think that the AFC is not tuned in properly. But all the other repliers are right as it is easiyl possible that you have a leak. Especially the hiss you can hear is a sound that could be the problem.

I for myself would start in removing the y-pipe to check it fully out, especially the TB gasket. Also the BPV should be removed and checked. Furthermore, remove the soft-IC pipes and check them out for any cracks. If everything is ok and you but the stuff together, eliminate the boost controller simply by reconnecting the stock hose from the y-pipe to the 4-way connector and the also make sure the stock boost solenoid is connected as well. The car must peak up to 10-12psi then max and you should not feel any problem. Of course, the AFC MUST be tuned in properly. If this test fails then I'm pretty sure that you simply dump fuel in what is not good.

Follow these steps to be able to eliminate possible problems. Also write down your findings for later reference.
 

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Discussion Starter #6
Thank you all of you for replying.

Brian,
you mean the TB gasket right? between the plenum and the TB? OK I'll check that one out...I will also follow Roger and VR4Tissimo's advice on checking all the hoses making sure there is no leak and no cracks...thanks

VR4Tissimo,
I have an ATR exhaust, EVC ez, AFC2, HKS SS BOV, K&N, my car started to run like this even without all these mods...it all started after I took it to KOEPEL MItSu and had them check the clucth cuz 2nd was grinding. after I got the car back...it was lacking in performance and after I changed the oil (as stated above) I pressed the throtle half way and I see the stock boost build up to 14psi when all of the sudden (not moving the throtle) I hear another hiss as if I had sequential turbos and I feel that the car is breathing so good and working effortlessly...BTW, I was bone stock then running stock solenoid...what can be the cause of this? wastegates getting tied up?

Roger,
thanks for your advice...but I really don't think is the AFC2 not being tune right cuz it's been running like this right after I bought it and took it to the dealer...before the dealer it was running super great!!! I will check the hoses, I/c, TB gasket, etc...could it be that my wastegates are tied up just like a previous post said...? that our cars are common to have this problem? I shalll take all of your advice and strip down my car....oh, even on stock solenoid the cars spikes up to 12 and then drops down to 8psi!!! that's something wrong right? please feel free to give me more insights...I can't stand driving without performance....I got the ebc just so because I thought it was the stock solenoid that was malfunctioning....but I guess this is not the case though it feels much better. with the ebc I can maintain boost at 15psi on 3rd gear, 4th etc...well I guess I'll have to check for leaks...OH, I forgot to mention that at one point I pulled out the tube that was connected to the stock solenoid to run 18psi...but even that didn't feel fast...can you explain what the heck is going on???? I am desperate!

Thanks again guys...and please fill me up with some insights
 

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Discussion Starter #7
billvp,
sorry...I left you out...thanks for your reply and I will look into the TB gasket as well...but did you feel boost leak when the broken gasket was on? I mean did the car feel sluggish?
 

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Well, running the car stock the 12-8psi sound pretty normal to me. No one know what they did as they checked the tranny or whatever. I just dont know how this could have an influence to the power ! They only possible cause is that the fried something, bent a tube or whatever. The tear-down of the vacuum stuff is done in a few mintes, but I'd especially check the IC hoses and the y-pipe as the gasket there is known to crack, leak and more. And no I doubt Brian meant the gasket betwen TB and plenum as this one will not be removed when one works on it. But the whole intake trakt is removed then to gain access to the tranny and therefore I think the problem is somewhere down there ! Start with removing the y-pipe, IC hoses, filter, MAS, BPV, intake rubber parts leading to the turbos. For better access to the rear I also suppose to remove the battery. And no, this is not complicated at all and also doesn't take too much time. When puttign everything back together make sure that theres is no leak, the clamps not too tight and the stuff properly aligned. Be careful in getting the y-pipe back onto the TB (you may use some grease or so).

Good luck !
Roger
 

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Discussion Starter #9
roger,
thanks for replying again..I can always count on you! well I have done the spark plugs myself so removing the y-pipe is no problem and yeah I do use some high vaccum grease when i try putting the y-pipe back into its position...Ok I'll check all the i/c piping and i/c, TB gasket, the HKS ss bov is fine cuz I just checked that yesterday...but don't understand why I have to check the MAS being that it's a whole piece? can you elaborate more on that roger? and also...why would I try to take the battery out? what sort of hoses run under the battery assembly?
 

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The MAS should be out for getting all the rubber stuff out. Or how you want to check the large rubber hoses going to the turbos ? And without the battery, it's much easier to get onto the stuff
But when you removed the y-pipe and clamps and smaller/larger hoses you should be fine.
 

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Discussion Starter #11
oh, ok roger...I understand...you mean get the hoses that go to the turbos out? but those are only intake hoses for they are not under pressure when boost builds up...can you explain why I must take those out? I will take the whole I/c system out to check...please get back to me roger will you?


thanks!
 

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Yes, you are right but this was one of the problems we had on a friends car where we installed an EU engine in an US Stealth (with 13Gs). We did not look properly and one clamp was loose and when we cranked the engine up it runned (i.e. vibration) But after a few minutes one of the hoses was so loose and it fell almost off. But this was enough to suck in unmetered (unfiltered air) and idle became damn crappy. The behaviour was almost the same as when any IC hose was loose or leaking. Of course, you do not have pressure before the turbos but I like to keep as much eventualities in mind as possible ;-)

Good luck !
Roger
 

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Discussion Starter #13
roger,
my idle is fine but I shall check the hoses anyway...cuz anything counts...thanks roger! take care!
 
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