Over boosting

[babajangas]

Well finally solved the over boosting issue thanks to weeksa from the forum!!!!! Turns out the grub screw on the turbo needed a couple of turns instantly over boosting fixed power back and running sweet. I took it to a turbo shop to ask if turning the grub screw out could have any negative affects and the said when running a chip(stienbauer with boost control) and three inch exhaust on these hiluxes it's a good idea to do so as it restricts the veins from opening right up and over boosting. Hope this thread helps anyone with the same issues and saves them a lot of time and money thanks for everyone who chimed in and offered advice
Cheers matt

[danmcccc]

mine used to throw p1251 (overboost) and go into limp mode once every now and then... then i blanked the EGR and it does it every drive, it also now blows zero smoke so it must be more efficient and therefore making turbo spool that lil bit harder.... Remap and HKS module or a FCD can sort the issue but i think ill have a go at playing with the grub screw like you did babajangas and see if that makes a difference. how many turns did you go with?

[TheGreenThing]

How do you remove/reinstall the actuator? Pics would be appreciated

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[onejayzee]

Babajangas what is this 'grub screw' and where is it located?

[fracturedranga]

The grub screw is at the bottom of the actuator arm locked with a nut.

[Luxxy2005]

Old post sort of

How many turn on grub screw? In or out?
Babajangas sent u PM too

[cooganstein]

Hey danmccc did over posting problem stop for you with grub screw adjustment? Also is your egr fully blocked or does yours have a hole?

[danmcccc]

yeah so adjusting the grub screw DOWN about 2mm has fixed mine. sometimes the boost still creeps but only very very rarely... i would call it FIXED

[sixes]

Driving from Darwin to Vic. 2012 Hilux D4D manual, loaded up but nothing unusual.

Cruising around 110/115 in the NT. Sitting over 2100 RPM. After a few hours of driving I hear a regular sound like a low whistle / whooooot. This varies from ~2-10 seconds and goes away. Will come back every so often, more often than not.

I have a scangauge plugged into the OBD port and it shows (at time of the noise) max boost of around 13psi and when sound goes away, the boost drops to normal pressure. No codes have been identified.

It has me worried as if I sit on a speed of around 94km/h (2000 RPM) the noise is not heard.

Noise goes away on 3/4 to full throttle but comes back when I back off to cruise speed.

1. All vac hoses are secure. What else can I check?
2. What part/s are liable to common break and easy to replace?

Typical something goes wrong on a road trip but this is really doing my head in and needless to say the lovely gentleman at Toyota was of no use at all and said I need to remove dual filter and Provent before they would look at it.... yeah riiiiight.

Any good info or tips would be greatly appreciated.

[TOYZX]

What exhaust do you have? What is the normal boost you are seeing at 110-115? I know mine with the egr blocked and 3 inch exhaust on 33s sits around 12-13psi at those speeds.

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[sixes]

Standard exhaust, normal boost around 6-9psi flatish terrain. 30inch tyres and speedo is accurate

[TOYZX]

Maybe put a boost gauge in to monitor it more closely. Could be a dodgy stepper motor in the turbo or simply just a bit sooted up in there.

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[sixes]

Car has 180k on her so possibly the stepper.

What controls the boost? Where does the OBD port get the boost signal from?

[Gipsy]

Maybe normal, do you normally travel at that speed? Just a slight rise in the road when the transmission is locked in od gear a slight rise unnoticed makes demand on the ECU asking for boost. Mine whistles at those speeds with a slight increase in load.
You have cruise control? It will do that on the slightest incline or even a slight headwind.

[TOYZX]

Gipsy makes a good point! Didn't think of that![emoji2357]

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[sixes]

Do I normally travel at 110? Ummm ofcourse....

So let me paint a picture:
Travelling on flat ground, 110 km/h at around 2200 rpm. Boost is around 6-9psi...
Noise is heard and boost spikes to maximum for a few seconds...
Noise goes away and boost returns to normal range.

Driving under 2000 rpm, noise is not heard nor boost spiking.

As mentioned by TOYZX, the stepper motor could be playing games and on its way out but would it make the noise? Is that what allows pressure to build and the ECU then dumps the excess through the EGR? I have seen these for around $400... are they easy to bolt on? I have not really looked that far yet.

I am happy to fix parts that could be farked but genuinely seeking info as to what this problem can be. Surely I am not the first?

[DeadlyBeast]

Nope...
Overboosting

[Gipsy]

Sixes, the stepper motor alters the vanes in the turbo to increase boost. I'm not convinced it's faulty but it could have an intermittent fault. In my original reply I mentioned 'load', it could be that at the cruise speed you talk of the load sensor in the ECU system is just on the parameters which asks for more boost which is normal. If you had a fault you would eventually throw a code. Don't worry yet, wait until you get a code then you will see what is causing it.
Look at overboosting thread as DB suggests above. There is no 'dumping' by the ECU through the EGR as all boost is controlled by the stepper and thus the variable vanes in the turbo.

[sixes]

Thanks, no code thrown yet and only a quick drive of around 800km to go.

I had a look at all the hoses and no leaks were found (from what I can see).

I forgot to mention that in Tennant Creek I found the small vacuum line with the purple band was pulled off from the silver EGR Valve No2 (silver disc with push rod). I think that was removed from when I cleaned out the little filter. Anyway, all good.

Cheers

[DeadlyBeast]

Good result
Threads merged