Thread: TD5 Turbo issues

Originally Posted by e166735

Hi All,

Could it be a dodgey gauge, It is a electronic stepper motor gauge and its the first one i have used so not sure about them. When the gauge is reading vacuum .

Hello,
If you are running over the 1 bar (14.5 psi) boost for more than a few seconds then you will get a fault in the ecu of over boost this will cut the fuel and you will get your hopping effect running 20 psi will do this. To fix this you need a boost box. As for you gauge reading a vacuum from the actuator pipe, NO WAY this is always positive when the engine is running, not unless you have hooked up to the old EGR pipe. From what you say it is a Discovery if you bypass the boost controller with a normal turbo not to sure how that will work, the ecu needs to control this. I would say get a new boost controller, and either get a boost box or turn the boost to under the 14.6 psi. and see how it goes.
Ian

Originally Posted by justfishing

Hello,
If you are running over the 1 bar (14.5 psi) boost for more than a few seconds then you will get a fault in the ecu of over boost this will cut the fuel and you will get your hopping effect running 20 psi will do this. To fix this you need a boost box. As for you gauge reading a vacuum from the actuator pipe, NO WAY this is always positive when the engine is running, not unless you have hooked up to the old EGR pipe. From what you say it is a Discovery if you bypass the boost controller with a normal turbo not to sure how that will work, the ecu needs to control this. I would say get a new boost controller, and either get a boost box or turn the boost to under the 14.6 psi. and see how it goes.
Ian

The ECU won't limit until around 21-22psi boost. The 14.6psi is way off, and is actually a bit less than stock.

This is a recent Nanocom recording from my D2, with no boost box installed and the wastegate adjusted to give a 3-4 psi extra boost.



This shows just under 60 seconds of boost levels above 14.6psi, and 46 seconds above 16psi.



The above shows the wastegate modulator duty and boost in psi on the same run. You can see that the modulator is fully closed below around 10-11psi so no pressure reaches the wastegate actuator. With the modulator bypassed the wastegate actuator will be partially open from 7-8psi which means the turbo is producing less boost than it would with the modulator connected. It doesn't effect maximum boost at all, just the level of boost in the 1000-2200rpm range, which improves tractability.

The quick and simple way to check if it's the gauge would be to hook up a diagnostic tool and compare the manifold pressure reading with what the gauge is displaying. It does sound like there is a problem with the gauge or installation rather than anything with the actually pressure.

cheers
Paul

Originally Posted by OffTrack

The ECU won't limit until around 21-22psi boost. The 14.6psi is way off, and is actually a bit less than stock.

This is a recent Nanocom recording from my D2, with no boost box installed and the wastegate adjusted to give a 3-4 psi extra boost.



This shows just under 60 seconds of boost levels above 14.6psi, and 46 seconds above 16psi.



The above shows the wastegate modulator duty and boost in psi on the same run. You can see that the modulator is fully closed below around 10-11psi so no pressure reaches the wastegate actuator. With the modulator bypassed the wastegate actuator will be partially open from 7-8psi which means the turbo is producing less boost than it would with the modulator connected. It doesn't effect maximum boost at all, just the level of boost in the 1000-2200rpm range, which improves tractability.

The quick and simple way to check if it's the gauge would be to hook up a diagnostic tool and compare the manifold pressure reading with what the gauge is displaying. It does sound like there is a problem with the gauge or installation rather than anything with the actually pressure.

cheers
Paul

I am now 2 weeks out from a month up at cape York, I have just ordered a nanocom evo, and the waste gate on the turbo was sticking shut so I have ordered a new turbo, this one has seen out 330,000 ks so it has done well. I ordered a vnt turbo technics turbo from bas in the uk. I have also sent the gauge back. I found that the pipe coming from the ic pipe to the boost solonoid had been oil effected and when engine bay heated up the pipe was sucking shut, prob worth while checking on all higher mileage discos. My ic hoses were doing same thing 6 months ago. Thanks for all your help everyone. My next post will be about installing the vnt turbo when it gets here Thursday.

Originally Posted by e166735

I found that the pipe coming from the ic pipe to the boost solonoid had been oil effected and when engine bay heated up the pipe was sucking shut, prob worth while checking on all higher mileage discos.

Yes, it's definitely worth checking. The hose between the IC pipe and wastegate solenoid shouldn't suck shut. It is actually subject to boost pressure + pre-intercooler temperatures which can easily be in the range of 100°C. The combination of heat/pressure and a bit of oil can reduce hoses to jelly very quickly. I've had SuperCheap vacuum hose fail within 2-3 months in this position.

cheers
Paul