adam120674

iTrader: (2)

I have a 99 z28 with twin turbos (truck manifolds) .62 a/r with internal wastegate set at 8psi. I have oil in my charge pipe (i think, I see it under the blowoff). Moved the turbo up about a month ago,plenty of drop for gravity to do it's job. No boost, installed boost controller no help, tighten the rod on the wastegate actulor, checked piping, looks good, Switched internal wastegate refence line, no help, tightened intake manifold, no change.Boost gauge reads 20 vac to 0 when accerating. Wondering if it is my engine, replaced with a used one from a juckyard after I bottomed out and cracked my block with a rear mount turbo that I done myself (had no problem with that, except when I bottomed it out). Went to front mount so that wuld not happen again. Is it possible it could be my engine, compression wasn't nearly what my old one was?Can turn it with a small rachet when tighten the flywheel.

Fondle

iTrader: (4)

you should still be getting boost, where is your boost gauge referenced too? can you hear your blow off valve go off when driving?

possibly your wastegate on your turbos are stuck open? seems odd that both would be stuck though

MY99TAWS6

iTrader: (3)

Can't see both turbos going out so would think you would have some boost. Sounds like boost is not getting into engine. Turbos can work with pretty low compression. I guess do compression test at least some easy cylinders for starters. Also each turbo has an internal gate ? If so again then should have boost from at least one of them if the gate was stuck open.

Still put my money on boost leak.And huge one if you are getting no boost.
If you have non beaded pipes and non t bolt clamps or not high quailty silicone couplers pretty easy for one to come off or tear maybe.

adam120674

iTrader: (2)

boost gauge coming out of line coming out of intake on drivers side that runs back to fuel line. moved blowoff refence to brake booster , because I heard it wasn't good to refence wastegate,gauge and blowoff out of the same point. Very light if any sound on blowoff. You can hear turbos spooling up fine , just no boost.

Camaro Chris

iTrader: (1)

Do you have pic to post of the set up you got?

XtremeDime

iTrader: (16)

Sounds like a malfunctioning boost gauge or an awful boost leak.

BadgeZ28

iTrader: (28)

I assume it is a dog when accelerating compared to when you had boost? Can you see the impellers turning on the air intake side of the turbos? Are you running an IC? Can you bypass the IC going directly into the intake? Is it possible to check the internal waste gates? Just a few ideas. Good Luck

MY99TAWS6

iTrader: (3)

Yeah if you hear turbos spooling up sounds like huge boost leak pre tb or as said your boost gauge is not working right.

Assume blow offs are not leaking the boost out..what type of blow off and did you change settings on them lately?

Sure you dont' have coupler off or ripped.That would give no boost into the engine.Could intercooler be leaking big time ?

Seriously not much else it can be .As said not likely for both turbos to be blown and unlikely engine. If you really blew engine would expect giant clouds of smoke.

adam120674

iTrader: (2)

Ok still no boost. Replace some t-bolt clamps and some couplings that looked worn or in bad shape. Left unhooked at tb and reved engine . Can feel air pushing out ( a good bit of it) . Tighten intake manifold . (no good) Is it possible a crack in the intake that I can't see or a bad gasket??? Boost gauge shows a good vacume (20hg) Would this happen if intake manifold was cracked

Tzion_ben_Arthur

iTrader: (19)

This may seem like an odd question, but could you post some pics of your system, BOV and WG. Let us get a visual. sometimes a new set of eyes can help.

When you bottomed out, did you intercooler get hurt?

MY99TAWS6

iTrader: (3)

Well..still has to be what was said before. Almost impossible for two turbos to have no boost. Simply unhook lines from gate, put screws in the lines or golf tees. Carefully push on gas when car is under load and watch boost guage.
You will of course have no boost in neutral just revving it up you have to drive the car around.Auto can build some boost brake torquing ,more on two step. Manual cars dont' really build any boost just revving it up.
And leak would have to be massive to have zero boost. Its not a vacuum leak if you get 20hg vacuum at idle. Its boost leak ahead of the tb.
Time to start listing your hardware..all of it..what type of blow off,are there two or one blow off? Gates shoudln't both be leaking ,one mabye but not both.
Try replacing pipe or hose to bypass blow off or intercooler for temp testing. You can run no blow off or no intercooler for testing.
Intercooler if its cheap one can easily be leaking huge.Cracked,split..etc.
As said if engine was blown you should see clouds of smoke.
But it cant' hurt to do compression at least on some cylinders that are easy to get to.And leakdown if you find compression really low.
Cracked intake is going to show low vacuum not 20inch hg.
This should be simple to find.
List all your hardware, take pics of things. Take off couplers and recheck ,might have torn one.
Coupler not on right can give no boost.
Possibly make boost tester with home depot parts and compressor.Some plumbing parts, and bicycle tire valve can make a boost tester or try to go get automotive smoke machine test.

stevieturbo

It isnt rocket science, and nobody is going to diagnose such a basic yet major problem without a good visual checkover.

If the OP cant do this himself, he needs to take it to someone who can.

ta02zx10r

iTrader: (19)

If it's a boost leak and you're getting 0 pressure you should be able to hear the leak unless you're deaf.

adam120674

iTrader: (2)

Ok, re routed pipe and took out intercooler. Getting 5 psi , still not 8 but headed in the right direction. Loosing a decent about of exhaust air around the weld on turbo flange, could this restrict my turbo and be where my other 3 psi is going?? (Damn flux core mig wire )

MY99TAWS6

iTrader: (3)

Well if you picked up 5psi when you bypassed intercooler it must have massive leak in it.So now you got 5psi back..getting there.. And anything that stops exhaust gas from going into turbo will hurt boosting ,how much depends on how bad the leaking.
I once had gasket get sideways in one of my talons and really caused some issues with boost,gasket between exhaust manifold and turbo.

Maybe the turbos are not doing so great. They can boost but still be fubared although as said you have two so one can sometime make up for a bad one. Also not sure but that Ar might be too tiny to get maybe max boost..Did you get 8 before and now suddenly you don't have it or you never had 8? Are the gates moving freely opening or closing properly. I think time to start giving us some hardware specs..type of turbos,etc.
If this is a cut all the corners build with knock off parts that might be part of the answer. Blow off can bleed off 3psi as well if its not closing or set right..intercooler does sound like its got massive leak,etc.
So list all of it now and likely can give more help.

pwrtrip75

iTrader: (8)

If theres a boost leak the turbos should be trying to still reach their targeted PSI....so it would be blowing and hissing or whistling out of somewhere.

Ive split my intercooler and intake before.....air blowing out is loud. Sounded like a super turbo under the hood. If you have little air blowing off....and not reading much boost.... ever consider that its not set to make much boost? Crank it up.

ModularTurbo

iTrader: (14)

Call me lets get this figured out!