North American Turbocoupe Organization



help! no boost! wierd story!
tyler477 Offline
Junior Member
#1
ok, so just got my ride [Image: biggrin.gif] and it has a rebuilt turbo on it. 119k recently ground heads, here is the prob...


when i first got it the turbo did not work, it was locked up from sitting for 2 years. i did work on it one day... this is what i did;

installed different 02 sensor
unlocked turbo
tightened belts (were loose and sqeaky)
put on different exhaust (needed a cat for emmissions)
checked the dizzy
new air filter


then it drove great!!! i was turboing all up and down!......then terror struck, i was turboing very quickly up a hill and i cought major air!!!! [Image: cool.gif]

about a minute later on the freeway i heard a loud hissing sound from under the car and lost my boost....
checked the hoses and there are some cracks in one but none of the cracks go all the way through. checked the turbo and it still spins tried and true(does not rub)
the hissing (i think) is coming from the exhaust pipe inbetween the cat and muffler.
i'm not so worried about the pipe leak but i need my turbo!!!!
so this is the major question.. also today i noticed the belts were not as tight as i had set them the day before (was squealing at idle) if the belts got loose in one day could that have thrown my timing, from the jump?? i have no boost... nada, and car is sluggish as hell. the day before though it was running like it was just off the assembly line. the only reason i question it is cause i heard a hissing sound and it is related to other problems with the turbo... thanks in advance for helpin' a noob.... this place is great!!
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Nsw Offline
Senior Member
#2
well getting air cant be good for anything. a leak in your exhaust behind the turbo would not really effect it. i would say check the wastegate to see if it operates or if its stuck open. i would also check all the vacuum hoses around there
1988 5speed black every option. 3inch single turbo to tail(stinger), manual boost control. k&n cone walbro fuel pump

1986 xr4ti project car..... way to many mods to list.
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tyler477 Offline
Junior Member
#3
the wastegate isnt stuck, where are the vacuum tubes?
thnx for a quick response!
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rpratt Offline
Senior Member
#4
I suspect that you blew the line off of the boost gauge, that is the hissing sound, and the gauge isn't moving because it doesn't "see" any boost.

I suspect that it runs almost the same as far as performance though, doesn't it.
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TurboE Offline
Posting Freak
#5
I had a similar problem and even tho they looked fine (no cracks to my site) replaced the turbo to intercooler & intercooler to throttle body hoses and all the sudden back to normal. Forced4 in the vendors section sells them for $25. Any time i hear the "hissing" noise its normally them or occasionally another vacuum/boost line.
-88 TC Black
5spd, Precision SC50 T3/T4, QH/SD Tune, Gillis, AFPR, 255FP, WB O2, K&N, Ported E6, 3" DP, ATR 2.5" Duals, 3:73 Rear, Konis, Eibachs, 18" Voxx Wheels, X Drilled Rotors.
-06 G35 Coupe Diamond Graphite
-97 Pathfinder
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tyler477 Offline
Junior Member
#6
no, the boost is gone, no power, i could tell immediately... the hiss i thought was coming from the exhaust pipe, i can feel exhaust coming from the pipe and i can hear the hiss from the spot on the pipe, that is why i thought it was timing rather than a busted hose. can someone show me a diagram on where all the vacuum hoses are? i have never dealt with them.... also i need an answer on the timing belt as i was going to get it timed today.... thankx guys!
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Pete D Offline
Administrator
#7
Vacuum diagram for 87-88 http://www.turbotbird.com/FAQPage/Vac_Diagram.htm

What belts were loose and squeaky? Not trying to be a wise ass, but do you know which is the timing belt and which are the accessory belts. See this article for how to determine if the timing belt jumped position: http://www.turbotbird.com/techinfo/CamTi...Timing.htm

Also I would replace the intercooler hoses, the two big ones. If they are cracked, they could be leaking. Also make sure the lower one is properly positioned and clamped
Pete Dunham


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TurboE Offline
Posting Freak
#8
I was going to say the same thing about the timing belt, that doesn't sound as likely, as it would not be boost related, and with a jumped tooth it would run rough an have no power but should still try to boost. You may have a combination of leaks exhaust and intake in my experience exhaust leaks are LOUD and intake leaks HISS.
-88 TC Black
5spd, Precision SC50 T3/T4, QH/SD Tune, Gillis, AFPR, 255FP, WB O2, K&N, Ported E6, 3" DP, ATR 2.5" Duals, 3:73 Rear, Konis, Eibachs, 18" Voxx Wheels, X Drilled Rotors.
-06 G35 Coupe Diamond Graphite
-97 Pathfinder
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tyler477 Offline
Junior Member
#9
went to mechanic and they want to cahrge me 350$ for timing and new belts!!! if i do that and it doesn't fix the turbo i will be mad!!!!! would it be stupid for me to do this? the car doesn't run rough, it just has no boost. it doesn't even try to boost, the boost guagu works but always stays in the vacuum. how do i test the vacuum hoses for leaks? any other thoughts of what might be wrong?
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Qwertys Offline
Senior Member
#10
i'm betting its not the belts.
double and TRIPLE check the IC hoses and make sure the wastegate vacuum line is connected properly.
there are only 2 things that will cause hissing, exaust leak, and boost leak. if you hear your turbo spool up then its a boost leak, if you smell exaust in the engine bay and hear a small "putt-putt" sound then its an exaust leak. check your manifold bolts. its also possible the manifold to turbo gasket went out.
also if there is a gasket on the manifold to head then you WILL have a leak.

but from the sounds of it you have a boost leak. even the smallest of leaks/cracks in those hoses will cause olmost 100% boost loss. those rubber couplings tend to crack after a long time or they get loose or when you put them on you don't get them on right.
but make sure there is no shaft play in the turbo and make sure the turbine or compressor wheel isn't cracked or damaged.
'85 TC BPV and Ford FMIC
'88 TC Kirban AFPR, Autometer Boost, FP and A/R Gauge, 8.8 to 4.10 rear, Walboro 255lph Fuel pump, Garrett GT3071R T3/T4 Dual Ball bearing Turbo, Custom AWIC.
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