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Discussion Starter #1
Well after a night of racing (and winning a few) my #2 Turbo wont come online anymore... these are the low mileage twins I just put on... there is no foul noise, the boost never goes above 11-12psi... and when #2 should be coming online my boost guage only shows #1 spooling down... there is no movement or odd characteristics when I hit the #2 rpm range... just #1 spooling down...

I checked the #2 turbo actuator hose or whatever you wanna call it that popped off a week or two ago and caused the same problem.. it was on securely... I looked as best as I could all over the engine bay and found nothing... however on the other side I THINK its for the EGR one of the hoses was off the little blue nub because the wire clamp was loose as hell... we put that back on, all it did was stop a hissing sound... no effect on #2... I checked all hoses around VSV... etc... I dunno what to check now... I cant find anything loose... so suggestions are very much appreciated... I wanna get this back to working tommorrow so I can have more fun... there is no death whine or sound at all.. #2 doesnt even seem to be awake.. so... Im clueless.

Im sure the suggestion of TTC will pop up... Id like to try everything else first, but I may go TTC tommorrow if its my last hope... im automatic bpu btw.. so lag might suck, but if it prevents killing #2 Its all worth it Id say... but ANYTHING I can check and hopefully may be a solution Id like to hear, thanks a ton.
 

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I had a similar problem and it turned out to be a bad vsv for the IACV. don't worry about the lag in TTC you are only doing it for diagnostic reasons( in a 6spd however I love it ) if this solves the problem then you KNOW that it has to be one of 4 things I am going to quote from a letter sent to me on mkiv list

FROM JOHN CRIBB
If any of these valves aren't working properly, you'll have low end boost problems:

1. BOV (boost will get bled back to intake)
2. EBV (loss of exhaust energy)
3. EGCV (loss of exhaust energy)
4. WG (loss of exhaust energy)

Now if the EGCV, or EBV aren't working properly, you should have strange transition problems, as well as low boost on the low end.

If the problem is the WG, you should suffer low boost consistently, whether it's only #1 or 1+2.

If you're suspecting a stiff/sticking EBV, try pressurising its actuator with air and see if the motion is jerky. This is a real tough one to watch, especially on a hot engine.

Being a lazy individual and knowing that Supra failures tend to follow patterns, I'd look hard at the EGCV actuator. Mohd and others have found this to be one of the culprits of low boost.
************************************************8

Going TTC will isolate the whole transition dance tehn you can test the components ( or in my case replace them ) one by one. Do the temp mod with the check valves. VSV can go bad the egcv diaphram is notaious for failure the pressure tank can go bad. Remember by upping the boost on an older car we are stressing older components which were not designed to see 18 psi. This whole thing should be in a FAQ someplace , if you read this forum regulary it is as common as dirt. Hope this helps some
 

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Discussion Starter #3
Thanks for the info... are these check valves something I can ONLY Get at Toyota... this sucks, because it looks like I most likely need to ORDER parts or replace something, I dont wanna wait I want my car back today :(

But hopefully its not a big deal... I just hate waiting for Toyotas slow ass to get parts in, if it was monday I suppose I wouldnt really give a shit... but im gonna go check extensively under the hood... thanks for the information :)
 

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Discussion Starter #4 (Edited)
would ETTC work too... if I cant get those check valves?

edit: I called Autozone and they told me to try a PET STORE for 1 way checkvalves because they use them in aquariums or something lol... I guess Ill give it a try, cant hurt I suppose.
 

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Discussion Starter #6 (Edited)
I actually found some vac checkvalves at Napa so its all hooked up, I went for a drive... I do have the louder exhaust note but the highest boost I could hit was 13lbs... I was running about 20lbs on my modified stockers... so something is still wrong..

If I go TTC and I still dont get my monster boost does that mean I have a big problem.. like #2 dead (again), because thats really going to piss me off... I dunno what to do now... this car is driving me nuts :(

I dont know how to 'test' all of the VSV's and what not.. Im just doing anything I can find on mkiv.com... how would I actually test these? I dont have a huge tool arsenal unfortunately :( ... the only thing I can see is replacing them and hoping for the best but that could just waste money.. heh.. Im gonna try the VSV bypass mod, if that vsv is bad wouldnt bypassing it work?... plus does the VSV bypass mod work with TTC?

Thanks again
 

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whos slow down you don't need to do the vsv mod if you previoulsy did the t mod ( aasume that is how youhit 20 psi) if you are still not getting the boost you got before after going TTC it is not your vsv or actuators as that eliminates that possibility ditto the pressure tank. You could have a boost leak. you have an older car and the vacuum hoses crack after a while. The most likely place for a boost leak is in the tubing going from the ic to the throttle body check the worm clmaps( better yet go to napa and get t clamps you need the 2.75" the cost abotu 2 and change each part number is 705-1532 - 2.75") look under the rubber protector that covrs the ic hosing that goes into the fender some people have split it there. Pull the undre engine cover and look at the connectors. you can pressurize teh engine by gettign a plastic pipe cap and a schrader tire valve disconnect one of the ic hoses and pump up the engine with a bicycle valve it should hold pressure If you want to isolate the ic hoses put a soup can in the hose near the Throttle body. I bet you have a small leak somewhere . Usualy the turbo when it goes will give you hte death whine blow smoke and express it's mechanical displeausure in some other way then low boost. BTW if you keep on hitting 20 psi+ you will blow the turbo sooner rather than later. I understand your frustation however teh twin turbo system is complicated it is an older performance car and you did modify it. Don't expect it to behave like a Camry.
 

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Discussion Starter #8
I did pull the IC hose off that goes into the fender which was over the Intake... it had a little bit of oil in it... I have not checked the IC hose that connects to the throttle body, although it does look a little old for sure so maybe that will help... my friend said it smoked a little... some white smoke which he thought was 'dry' but im not sure how accurate that was, I never saw it he saw it cruising behind me last night... but from what I hear Supras smoke for a number of reasons a lot... and it was just little bits out of the exhuast I think.. plus it was about 38 degrees so half of it was probably steam from hot air hitting cold.. I hope

Im not too sure what you meant about the soup can thing.. and if I disconnect the IC hose, and put a plastic pipe cap in it... how will it hold boost if the other end is completely disconnected? I have a general idea of what you are saying.. but I cant quite picture it perfectly.. where do you connect the pipecap and the bike valve... underneath the bumper where the IC hose runs... over the intake area where the IC hose runs to the turbo setup?... where it runs to the TB?... if I disconnect it do I need to somehow plug the other end of the IC hose which is going to be wide open.. last time I checked a pipe cap isnt gonna cover up more than one of the openings created from taking the IC pipe off :D

I wish I had photos of this stuff, photos make everything click instantly.. once again you are being very helpful and I appreciate it... the only reason im running 20+ lbs is because of the weather and boost spikes, I dont have a boost controller yet.. but I was told it should be fine since my turbos are ported/polished.. but thats just going based on what other people with similar stockers have said to me... once again thanks hopefully I can get this sucker working...

BTW... Im hitting about 13lbs... in TTC... and if I remember correctly #1 wont do more than about 10-11lbs by itself... so maybe #2 is giving me a LITTLE... but it wasnt giving me jack shit in sequential mode.. but in TTC im getting about 2lbs more boost.
 

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Discussion Starter #9
Oh yea... and I do here a 'hisssssssssss' sound under the hood... which is pretty faint, my car always made that sound though, even when I boost fine... but it does make me think there could be a leak.. its not like a LOUD HISS its just subtle when the car is idling.. I cant isolate the area either :(
 

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Discussion Starter #10
lol I keep having more little things I need to report... so here is another... Im not even 100% sure where my pressure tank is, but judging by the looks of things, I think its the big black tank on the passenger side RIGHT next to the fender near the firewall right? it has 3 black hoses coming off the top of it... Im guessing thats what it is...

Anyway, when I was messing with the IC hose that goes into the fender, just putting pressure on it and moving the rubber protection sleeve thing all of a sudden from what I think is the pressure tank a wierd quiet "brr r r r r rr r rr" sorta very low volume rattle almost came from that area... then I pulled the hose off, middle one which runs to the turbo assembly and kinda knocked on it with my hand and it made that same 'rattle' sound until it stopped vibrating... is that a sign of anything? it was odd so I figured I should post it as well.
 

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disconnect the ic tubing where it connects to the y connector on the turbo collector. Leave the other end on the tB on this will pressurize teh whole engine. If you disconnect the end at the TB you have to plug it up ( soup can) or you cant' pressurize it. The 1st stocker can make 13 psi by it self sorry and porting and polishing won't give you turbos any more longevity at over boost they may make them more efficent. Turbos fail for two reaons the bearing get fucked up after a while and #2 when the 2 nd turbo sees the higher than normal boost when it come sonin a rush you get shaft twist. That is why a lot of people at BPU run TTC becasue since the boostis more progressive and you eliminate the chance of a foul up formt he sequential system you decrease the chance of it not perfroming properly and fubar your turbos. any way hope this helps
 

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Discussion Starter #13 (Edited)
ok cool thanks.... Im gonna have to run to a hardware store and buy that stuff I guess... I dont even have a bike pump.. but my neighbor does im sure... I dunno if I wanna keep up with this tonight or not.. but you have been super helpful... I am running through the MKIV list archives too digging up everything I can... I still have hope in me that #2 is fine.. since im not getting the death whine.. I blew my #2 no more than a couple months ago so I remember exactly what it was like... and the car is running great, just lacking the boost... Ill try all this stuff later and post what happens... I hear its supposed to be able to hold upto 20-30lbs for like 30 minutes if everything is perfect with no leak right?

Also... how big of a pipecap do I need... will it go over the metal y pipe or inside it, im assuming the pipe cap will be threaded, so do I just jam it in there securely?... Im not sure what size it is so Im gonna take a ruler to it right now... looks like 2.5" so thats what ill get and hope its ok :D ... but if I dont get there anytime soon... could you tell me what size pipecap to get and if it should go in the metal pipe or over it?... heh sorry I have so many questions, thanks.
 

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i'm going to home depot tommorow to get a cap to put in the ic hose at the y area. i know they don't sell 2.5, so it will have to 2''. hopefully i'll find my boost leak.

dzeiler, thxs for steeping up and helping:)

gl with your situation,
 
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