boost gauge fluctuates erratically

[wildplumdx]

engine 4d56 turbo

my boost gauge fluctuates erratically between +3psi and -3psi around there so fast its blurry at idle only, whats that mean ? ive hooked the gauge up to the manifold, didn't have a vacuum pipe off manifold so where ive plated over the ERG ive tapped a little brass fitting in there and hooked the gauge up there, also turned up the boost controller maxed it out and it didnt change anything ? ive hooked my controller from turbo to waste gate actuator line, also i had another problem earlier as my rpm gauge wasnt reading correct then i changed my turbo to fuel pipe line with a new one and its reading correct does that line control the rev gauge in some way ? so what i'm thinking is the waste gate line is also perish being same age and leaking boost ? i'm only guessing ?

[DieselBoy]

or the whole trucks just vibrating so much at idle its wobbling he needle around inside the gauge. Not as stupid as it sounds, because there's no pressure in the gauge at idle to keep the needle steady

[Pedro]

engine 4d56 turbo

my boost gauge fluctuates erratically between +3psi and -3psi around there so fast its blurry at idle only, whats that mean ? ive hooked the gauge up to the manifold, didn't have a vacuum pipe off manifold so where ive plated over the ERG ive tapped a little brass fitting in there and hooked the gauge up there, also turned up the boost controller maxed it out and it didnt change anything ? ive hooked my controller from turbo to waste gate actuator line, also i had another problem earlier as my rpm gauge wasnt reading correct then i changed my turbo to fuel pipe line with a new one and its reading correct does that line control the rev gauge in some way ? so what i'm thinking is the waste gate line is also perish being same age and leaking boost ? i'm only guessing ?

put a restrictor in line, will dampen the pulsations down, two methods you can use is a plastic fuel filter inline, or i used a cotton cloth forced into the hose, before it goes into the gauge,

pedro

[wildplumdx]

sweet i'll do that fuel filter one, also any ideas on the controller situation ?

[KiwiBacon]

sweet i'll do that fuel filter one, also any ideas on the controller situation ?

Block the line, go for a careful drive and see what it does.

[wildplumdx]

i got told to remove the wastegate line and go for a drive so i did and no difference ? whats that mean ? also kiwi i got a egt dial gauge with probe off trademe for 128, what would be the max temperature i would wanna go etc?

[KiwiBacon]

i got told to remove the wastegate line and go for a drive so i did and no difference ? whats that mean ? also kiwi i got a egt dial gauge with probe off trademe for 128, what would be the max temperature i would wanna go etc?

If that's the case, then it's probably boosting as much as it can with the current parts and tune.

For EGT's, the maximum you ever want to hit is 750 deg C at the exhaust ports.
If your engine model has a less than perfect reputation, then lower that a bit.
If you think one cylinder runs hotter than the rest, then lower it a bit.
If you think your probe doesn't get right to the centre of the gas stream, then lower it a bit.
If you think there's significant heat loss between your exhaust ports and the location of the probe, then lower it a bit more.

Once you've thrown all the fudge factors in, you probably won't want to go past 600-650, especially for sustained load.
Don't put the probe after the turbo, it's a waste of time that'll tell you nothing important.

[wildplumdx]

yeah i put the probe in before the turbo where the instructions indicated, also i think my boost controller is labeled wrong it has the sticker with arrow pointing towards waste gate actuator and when its in this position the one way valve wont let any pressure through? this is blowing through with my mouth, is that the correct way ?

[KiwiBacon]

yeah i put the probe in before the turbo where the instructions indicated, also i think my boost controller is labeled wrong it has the sticker with arrow pointing towards waste gate actuator and when its in this position the one way valve wont let any pressure through? this is blowing through with my mouth, is that the correct way ?

It has to restrict pressure to the wastegate can to work. So if you can't blow through it that way it's probably right.

[wildplumdx]

sussed it boosting 15psi no worries zip tied the pressure valve down kept opening at 13 14psi and lossing all my boost but i honestly havnt noticed a difference in power which sucks i mean 6-7 psi more i think it would have done something noticeable but no luck there so might go back to factory specs

[DieselBoy]

sussed it boosting 15psi no worries zip tied the pressure valve down kept opening at 13 14psi and lossing all my boost but i honestly havnt noticed a difference in power which sucks i mean 6-7 psi more i think it would have done something noticeable but no luck there so might go back to factory specs

You need to add more fuel into the equation if your putting that much extra boost into the system!!!!!

You should notice a decent power increase then.

Turn up the fuel screw on the injector pump.

[wildplumdx]

so what would i be forcing in extra at the mo ? air ? now i gotta find the screw and how to you go about adjusting it ? just trial and error?

also when i installed the boost controller i never turned it up it was turned right off and it gave me 15psi without adjusting ?

[KiwiBacon]

Extra boost will give you a little more efficiency, but not much noticable power, your next step is to up the fuel to match.

That's where your EGT gauge comes in.

[wildplumdx]

woah turned up the fuel and man does it go better! but once i turned up the fuel the 15psi jumped to 20psi so wasnt keen on that but it went so well, smoked alot, i think my boost controller is broke.... coz what ever changes i do doesnt change a thing! so i'm back to standard till i suss things properly, would be keen for a custom manifold to get rid of gases faster as i hit 700 egt at high boost, but yeah i know what to do now its just playing round so thanks heaps guys i'll let you know how i go.

[Bulletproof]

woah turned up the fuel and man does it go better! but once i turned up the fuel the 15psi jumped to 20psi so wasnt keen on that but it went so well, smoked alot, i think my boost controller is broke.... coz what ever changes i do doesnt change a thing! so i'm back to standard till i suss things properly, would be keen for a custom manifold to get rid of gases faster as i hit 700 egt at high boost, but yeah i know what to do now its just playing round so thanks heaps guys i'll let you know how i go.

Sounds to me like you have turned it up too much if it is smoking like you say. Before you alter the screw on the pump you should note where it was. Generally you would not move it more than an 1/8 of a turn.

Cheers Richard

[wildplumdx]

yeah i measured it before i touched it yeah is up to much just something i gotta suss over time, also my egt is getting too high i think at 3,000rpm at 100 k i'm at 700 or just under or 800 under hard acceleration according to hks 750 is max what would be the best way to minimize egt but still running what i'm running ? custom manifold ?

[KiwiBacon]

woah turned up the fuel and man does it go better! but once i turned up the fuel the 15psi jumped to 20psi so wasnt keen on that but it went so well, smoked alot, i think my boost controller is broke.... coz what ever changes i do doesnt change a thing! so i'm back to standard till i suss things properly, would be keen for a custom manifold to get rid of gases faster as i hit 700 egt at high boost, but yeah i know what to do now its just playing round so thanks heaps guys i'll let you know how i go.

A custom manifold won't do jack. Your EGTs are high because you're burning lots of fuel, the way to reduce them is to turn the fuel down to an acceptable level.

You've got three main concerns when cranking up the power:
The first is EGT's, sounds like you've got a handle on that.
The second is mechanical stress. Can your engine handle the new power level, can all the associated parts handle it (drivetrain, turbo etc)?
The third is heat production. 50% more power means your radiator and exhaust have to shed around 50% more heat than previously. Can they do it without first overheating the engine and secondly overheating something else nearby?

[wildplumdx]

was watching the radiator temp and didnt go up at all if anything but yeah i really need to take it easy i aint about to go nuts over it... as for the engine i have a spare if worse happens spare turbo too but not about to go use it lol i would have thought a better manifold would help ? what about he exhaust system itself ?

[KiwiBacon]

The only way to truely tell if the exhaust is holding you up is to fit a pressure gauge just after the turbo.
I've been planning to do this for a long time, but life keeps getting in the way. I do have pressure readings from my exhaust manifold but they include turbo backpressure.