Overboosting.

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rob300zx

Member +
Evening guys,

Ever since the day i bought the car its been overboosting, not long after the turbo died due to this and now its really starting to annoying me as I cannot put my foot down otherwise it will overboost itsself to death and would end up killing the engine/turbo.
Fairly recently i fitted a Greddy Profec A EBC and even that is not controlling the boost.
Ive checked all IC piping for any leaks etc, Ive taken off the manifold heat shield to try and feel if any air is pissing out of a crack but nothing, Im so confused.

Can anyone suggest as to what else I can check?

If i put it on the diagnostic will that maybe show up anything?
The HI/Low solenoid has also been removed before I got my hands on it.


Thanks in advance

Rob
 
Rory

Rory

Lifer
Have you tried putting it back to stock?

Take the Greddy out and run a pipe between the turbo housing and the actuator and see id it still does it.

Have you a rough list of what has been done to the engine?
 
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rob300zx

Member +
The car was stock when I bought it mate, apart from the HKS exhaust and HKS filter.

Since then ive added a FMIC, Greddy BOV and shortened the EFI pipe a tad so its got rid of the bend.

There was a pipe between the turbo housing and the actuator before I added the EBC and was still over boosting.

Rob
 
Rory

Rory

Lifer
So its still running a standard actuator?

Does it just boost as much as it wants, or does it get to a point, then creep to fuel cut?
 
Chris@CCM

Chris@CCM

Member +
port the waste gate on the turbo out it should stop the boost creep search for it been covered loads of times
 
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GTdan

In The Closet
hey bud

sounds like boost creep - same as what im having, was boosting to aroun 1.2bar and only stopped as we belive the injectors ran out of puff.

try putting the efi pipe/air filter back to stock - when you reduced the length of it, it sounds like its made it more free flowing.

Or as a temp fix, rap duc tape around the filter to restrick the free flowing air flow ive done this, its now boosting to around a bar and coming back down to 0.6ish.
 
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rob300zx

Member +
Rory - Yes mate, still running the standard actuator, I have a HKS waiting to go on.
In all honnesty mate i dont want to put my foot down to try and see what it will boost too, But i do remember it boosting to 1.2bar when I first picked it up and then the turbo died not long after.

My Apologise, I forgot to mention it has a JAM FCD also.


GTDan - The EFI pipe is pretty much stock mate, ive only just recently got rid of the 'S' type bend in the EFI pipe so its straight infront of the battery.
 
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GTdan

In The Closet
whats the boost controller set too??

can you bypass the the EBC and run it off the actuator and see if it still boosts?

the FCD will allow it go past 0.8bar, so if you remove this, you will hit fuel cut and not run at high boost.

have you got a decat?
 
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rob300zx

Member +
The Boost controller is set to 0.8.. but I can set it to 0 and it will still boost normally.

What do you mean bypass the EBC? Connect the actuator to the turbo housing?

I dont fancy removing the FCD, it looks complicated lol.

No i do not have a decat mate.

Rob
 
Rory

Rory

Lifer
Are you sure you dont have a jam actuator on there?
It would compliment the Jam FCD. They look stock aswell.

That would be reason why the boost controller cant control it, as the controller cant set the boost lower than the actuator set preasure.
 
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rob300zx

Member +
To be honnest mate i never even thought of that, And yes it does look totally stock.

Is there anything at all that differs the stock actuator to a JAM's one? If so il have a look and try and find out.

Regards

Rob
 
K

keirz

Member +
go back to basics, pipe from turbo to actuator. get the hks actuator on and set the boost just using that, if its still creeping port the wastgate or restrict the airflow. to be honest i would think that the hks actuator should sort it.
 
stedee

stedee

Member +
porting the wastegate will definitely help, i did mine and it hardly spikes at all now, it used to spike to 1.2 from 1 bar.
 
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rob300zx

Member +
Its an everyday car mate so porting it really isnt an option, if the actuator doesnt sort it then il be stumped on what to do next, ive tried restricting the airflow but that does not effect it in the slightest.

Might be worth a trip to toytuning or somewhere along those lines even if they are miles away, atleast it will get sorted.
 
Rory

Rory

Lifer
Nothing looks any diffirent to them, ive seen them first hand, and they look exactlly the same :(

Take the boost controler off. Run a line from the housing to the wastegate, and see what happens. Im geusing it will be 1.2 bar or there about.

if you have an HKS unit on order, then whip it on and set it as low as possible, without opening the wastegate, should be about 0.8bar.
Have a run and see what preasures your seeing, if ok, then put the boost controller back on and tune away.

If the problem persits, then see if anyone local can come have a look, and see if they can spot anything out the ordinary.

Porting the wastegate, will only help if the boost is creeping

Rory
 
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rob300zx

Member +
:(.. Yeah it will probably boost to around 1.2bar, but I dont want to try it mate incase i blow something IE the turbo or anything else?

I have a HKS actuator sat with me now, it just needs fitting.

Is is the further out the actuator rod the lower it is or the other way round mate?

Rob
 
kieran.s gt

kieran.s gt

Member +
rob300zx said:
:(.. Yeah it will probably boost to around 1.2bar, but I dont want to try it mate incase i blow something IE the turbo or anything else?

I have a HKS actuator sat with me now, it just needs fitting.

Is is the further out the actuator rod the lower it is or the other way round mate?

Rob
Click to expand...

lenthen the actuator to lower the boost and shorten it to raise boost
 
stuart

stuart

Member +
Let me know if you have any troubles Rob, you only a short trip away from us, although it is pissing it down at the moment :)
 
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