Editing Forums/Z31P/z31-repairs-forums engine-mechanical/Whats the matter with my Turbo

{{ForumImport
|op_user=CanadianTZ
|op_date=2009-05-08 06:38:36
|post_count=25
|archive_url=/Z31performance_archive/forum/z31-repairs-forums/engine-mechanical/7398-whats-the-matter-with-my-turbo.html
}}

'''CanadianTZ:''' <small>(2009-05-08 06:38:36)</small>

Boost comes on…Barely..It hits at diffrent times. It does not hit hard does not boost hard. But the Turbo still spins freely and has been Dailey driven like this for over a month. What could be causing this problem, whats my best option? New Turbo??

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'''DMANN:''' <small>(2009-05-08 11:31:09)</small>

Wastegate sticking, leak somewhere in the system, both.

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'''CanadianTZ:''' <small>(2009-05-08 18:58:06)</small>

Hmm. SO what is my best bet? Should i just get a new Turbo? It dosent seem like there is a leak in the system, leaning more towards the wastegate. As when You rev the engine in neutral the Turbo may boost a bit But There is no apparent wastegate movement, you dont see it move at all. Should i just take the Turbo off and see what i can do?

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'''Durkin:''' <small>(2009-05-08 19:06:46)</small>

when you say "hard" do you mean it does not boost to the factory PSI? do you have a boost gauge (non-factory) either in Bar or PSI? if the turbo original it could be seizing up. erratic boost can be many things, first off as mentioned, i'd make sure all the lines are intact and not loose. take the inlet off do you feel any play in the compressor shaft? probably as mentioned a sticky wastegate or a leak, but check everything, and can you give more information?

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'''CanadianTZ:''' <small>(2009-05-08 19:14:06)</small>

Sorry about the lack of detail. Im not shure, ive never seen a boost gauge? like a stock one. There is no aftermarket one. The Turbo Does boost, But it dosent hit hard like it should i know its not that big of a turbo but my Turbo Z is alot slower than my friends N/A. I might just start taking things apart and inspecting, seeing what the shaft play is like and inspecting the hoses. Should i get back to you guys then?

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'''DeleriousZ:''' <small>(2009-05-08 19:19:11)</small>

run your ecu codes first off.. that's the very first thing you should ever do when working on running problems.

find an aftermarket boost gauge, tape it to the dash if you have to…run its own source to the intake manifold if you can, if not, tee into a larger vacuum line.

take the intake piping off, check for shaft play in the turbo, both axial and thrust play.

inspect the vacuum hose that goes between your turbo's compressor housing and the wastegate… it's probably dry rotted and/or cracked after being exposed to that much heat for so long.

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'''CanadianTZ:''' <small>(2009-05-08 19:27:23)</small>

How do i run the codes? Also i do have a boost gauge but it's at my friends 45mins away! dang.

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'''CanadianTZ:''' <small>(2009-05-08 19:28:27)</small>

Oh and by axial and thrust play do you mean, how it spins and if the shaft moves up and down, i know a tiny bit of movement is acceptable.

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'''DeleriousZ:''' <small>(2009-05-08 19:45:25)</small>

[http://xenonz31.com/ECUcodes.html http://xenonz31.com/ECUcodes.html]

axial = side to side

thrust = in and out

the turbo should spin freely.

even a princess auto gauge is better than the stocker.

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'''CanadianTZ:''' <small>(2009-05-08 20:53:34)</small>

I skipped the whole ECU code thing for now, because ive never worked on these cars much and thought it would be fun. Ive disasembeled all the intake stuff, i found one minor crack in a hose attaching to the charge pipe but i think i caused the worst of it, i didnt think it was leaking…until now. Im having troubles getting the pre-turbo elbow to clear, im shure ill get it here pretty soon. As inspecting the turbo all lines look intact, i tryed moving the waste gate manually and i could move it with my hand and sounds like everything is working, opening and closing, is this a bad thing that i can use my hand?

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'''CanadianTZ:''' <small>(2009-05-08 21:31:32)</small>

Hold onto your seat boys.

Code 13- Cylinder Head Temperature Circuit

Code 21-Ignition signal missing in primary coil ( i do have Distrubutor ground disconnected)

Code 23-Throttle Valve Switch circuit ( Car warms up and idles fine)

Code 24-Neutral/ Park switch (What the hell, my car's a 5 speed?)

Code 31- Just random electrical things, i can handle this.

Code 34-Detonation Sensor

Code 41-Fuel temperature sensor circuit.

okay… Car just went on a 1000km road trip has been daily driven for over a month, only problem was the turbo and some exhaust leak issues. Now this, Where do i go from here. What Sensors can be swapped from my 86 N/A parts car.

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'''CanadianTZ:''' <small>(2009-05-08 21:44:27)</small>

I just got the pre-turbo elbow off, this turbo spins freely and has absolutly no shaft play at all, im not shure what the problem is, where is the stock boos solenoid on these things, or do they use one? im confused!

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'''CanadianTZ:''' <small>(2009-05-08 21:57:10)</small>

So for shits and giggles i turned the car on with no maf or no intake connected, car idles fine, i held the waste gate fully open while lightly reving it, the turbo was not boosting at all, im assuming due to lack of maf?, does this prove anything? What the hell is the matter with my car! i dont get it.

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'''Durkin:''' <small>(2009-05-08 22:15:09)</small>

if you're holding the wastegate open, it wont build boost, especially under light throttle because the exhaust gasses bypass the turbine and go straight into the exhaust system. if the actuator moves easily, that might be the problem, there should be a decently strong spring inside the wastegate actuator that holds the exhaust port shut, forcing the exhaust gas to turn the turbine.

and the car should idle without the maf, but after 2,000 rpms you might bog it down and stall. hopefully someone else can chime in?

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'''DeleriousZ:''' <small>(2009-05-08 22:18:31)</small>

goddammit, i had a whole post written out then hit 'back' on my mouse and erased everything (fucking IE at work)

anyway.

open wastegate = no boost, that should be obvious.

replace chts and its subharness.

fix your distributor.

recalibrate your tps… this causes idle and driveability issues.

was your car always a 5 spd?

fix the detonation sensor, it shouldn't be too difficult, it's either wiring or the sensor itself.

either fully disconnect your fuel temp sensor, or clean the connections and test the wiring.

DO NOT USE OR RE-USE OLD SENSORS you are just asking for trouble. get new ones from nissan.

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'''CanadianTZ:''' <small>(2009-05-08 22:40:06)</small>

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Sorry im not the best with cars, The open wategate with no boost, what is obvious about that? that the Turbo is shot?

Ya i believe this car was always a 5 speed.

Where is the fuel temp sensor? ill use my little book for that, chiltons or something i got.

replace chts and its subharness. What is this?

How do i recalibrate the TPS?

Sorry for being such a noob, im trying. And sorry about your deleted post that just sucks and thanks a bunch for all the help!

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'''DMANN:''' <small>(2009-05-08 22:50:26)</small>

It should all be covered in your Chiltons or haynes manuel where and how to test these things!

Your car won't build any boost if there is no load on the car/engine.

Where are your exhaust leaks?

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'''Durkin:''' <small>(2009-05-08 23:04:25)</small>

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basics: if the wastegate is open''', less exhaust gas spins the turbine, therefore the turbo doesnt build boost… think about it like that for now, till you research it more..

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'''nutsaq:''' <small>(2009-05-08 23:15:56)</small>

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uh, no, axial means 'along the axis'.

radial side to side. Not that it matter this post just had nothing else going for it.

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'''CanadianTZ:''' <small>(2009-05-08 23:44:38)</small>

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Ive got lovely exhaust leaks on the manifolds, More and more are building day by day, god dammit im broke.

And ya i got it back together.. i dont know where to go from here other than to replace those sensors…

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'''Durkin:''' <small>(2009-05-08 23:53:51)</small>

if the leaks on the manifolds are bad enough (i'm unsure as to what is "bad enough" ) you wont build boost. or, which seems likely to be the case, you'll have inconsistent boost.

someone correct me if i'm wrong, but that might be a major cause of his car's ailments?

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'''CanadianTZ:''' <small>(2009-05-09 03:22:14)</small>

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Car acted the same way prior to this exhaust leak, but ya, these leaks are definatly making it worse..

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'''DeleriousZ:''' <small>(2009-05-09 03:36:22)</small>

radial, not axial, my bad.

DOWNLOAD AND READ THE FSM. it is so many times better than the shitty haynes or chilton manuals.

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'''CanadianTZ:''' <small>(2009-05-09 04:26:26)</small>

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Alright will do, thanks.

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'''Z-day:''' <small>(2009-05-22 07:29:55)</small>

a bad enough exhaust leak will sometimes let O2 get in to the sensor thowing it off. you can also cook valves if i remember right. and no… you should not be able to open the wastegate easily by hand. check the diaphram in the actuator. if its leaking that can screw with consistancy big time. Anyone correct me on any of this, I am F^#&ing tired…