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Corolla D4D Lacking Torque


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Hi all

I've been a avid user of the forum when researching issues with my rolla but have decided to join and post as I need some assitance.

I have a 2004 D4D T3 with 160k on the clock and whilst it seems spirited to drive it seems to be lackjing in low end torque. from 3k upwards it seesm to fly but below that theer doesn't seem to be much which I thought was surprising especially fro a turbo diesel. After a lot of research the folowihg has been done:

EGR cleaned repeatedly and now blanked

SVC's changed

Inlet sensor cleaned

All inlet and vac hoses checked for splits/leaks

New fuel filter

No fault codes (other than EGR fault but tis makes no difefrence to perfromance once reset)

Forte fuel cleaner and turbo vane cleaner put through the tank

I've tested the VSV and this appears to be working ok, the actuator on the turbo is moving freely but only when unbolted from the turbo. It seesm to be very stiff when in place (very compressed spring) and when the engine is running the arm wil move a little under vacuum but not much. I've bypassed the VSV and tis makes no difference and I've not disconnected vac hose from actuator and blanked off which does seem to have made a little difference but not much.

Questions are as folows:

How much should actuator arm move when vac is applied at idle, should it move all of the way or only a little?

As I understand it is a variable vane turbo so the vanes move with boost/vac to help turbo spool speed. Is it boost that controls this or vacuum. I note that the vac line eminates from a device at the right hand side of the head that also seems related to fuel (fuel pump?)

Does anyone know what stock boost limit is? According to my OBD reader it hits about 12psi but only gets that far at 4k rpm and it seems very slow top get there.

I get a whilsting noise when it boosts which I thought was the turbo spooling up but when the throttle is closed I can hear boost escaping (a little like a dump valve) even with VSV bypassed so part of me is thinking a boost leak but I can't find anything. Coul dit be a leaking intercooler? I've checked and changed all vac lines I can see around turbo, boost sensor, VSV and intercooler, are there any I have missed? Is there a way of testing?

ANy help on tis woudl be gratefully received as I like the car but I don't thnk it is running right and safe overtalking is a mission.

Many thanks in advance


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A whistling sound would point to an intercooler/pipe issue. When you spool up the turbo, does the car go into limp home mode while driving by any chance? Also, check your turbo, to see if there is much oil coming out. They will put a tiny amount out, but a good bit would point to turbo cores worn and on the way out. There is a core repacement available online for most turbos, and this can be a cost effective solution, if you like to get your hands dirty, and the usual knuckle skinning also :blow:

I wonder if your EGR was gumming up a good bit prior to removal. Also, is it 1.4 or 2.0 diesel.

Also to note is will the EGR removal affect your MOT in future?

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Thanks for the response. Its a 2.0 D4D, the turbo outlet hoses are pretty oily but there seems to be a fair bit coming out of of the rocker breather so I think this is where it comes from.

No, no engine light when spooling up. Short of turbo removal and investigation is there any way of checking the core? More than happy to remove the turbo but it seems like a fairly big job due to lack of space. Been thinking bout intercooler integrity but wasn't sure if there was anyway to test. Have been planning to remove and clean out as inlet temps getting high and wondering if it is a little choked with oil so I'll give it a good look over. Any idea if it would be worth converting to a proper front mount, intercooler is in front wing and has never seemed a very efficient way of doing it.


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If you have a fair bit of oil coming from the turbo, i would think it is coming from the oil feed into the core bearings. If you have you turbo pipe off, catch the spindle of the shaft with two fingers and see does it rattle. These have a fairly tight tolerance when manufactured. As regards the overboost, i'm not fully sure about toyota, but on the VAG models it won't flag an engine management fault. What you may find is the intercooler is choked up with oil, due to the turbo failing (that is if it is).

Adding a bigger intercooler, may require a remap of the ecu.

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OK, cool, thanks, I think most of the oil is coming from the rocker vent as the inlet hose to the turbo is pretty well coated but I'll check the turbo for play. Pretty sure it doesn't overboosting, using readings from ecu boost seems to struggle to get to 12psi and very rarely goes over, certainly seems to run out of revs before it gets any higher.

Point noted bout intercooler and remap but as I understand the ECU's on these things are locked so no chance of that.

Thanks for your help

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Would sound like a turbo then, but a clearout of the intercooler could help. Hope it works out ok mate.

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