Low/Strange Boost on 2.0 D4D

[MrBenjaminHDM]

Hello,

 

I was wondering if anyone would be able to offer a bit of insight on a problem I'm having. I've had a remap done at a local garage using MonsterTuning for the maps. For the past year and a half I've been using a Tunit, I got fed up as it was shooting raw unburnt diesel out the back in the form of grey smoke. Now the remap was seemingly successful as the car kicks harder and seems quicker, however I'm experiencing a strange hesitation and upon hooking up to the OBD port and gathering some info the turbo doesn't seem to be boosting as high as some of the members on this forum are suggesting it should and it seems to fall off the face of the earth and come back. See the attached graphs, all are full throttle 3rd and 4th. In 5th and 6th it seems to judder like a bugger. 

Diagnostic steps taken so far: 
Checked for leaks in the hoses
Checked actuator for movement
Remapper says target boost is 20
Cleaned EGR (Closes at full load anyway)
Cleaned MAF

Guy that builds the remap reckoned it was either the actuator sticking which it doesn't seem to be or the catalytic converter has a blockage (The tunit concerned him) I had a stainless pipe from the expansion vessel back.
Car is back in the garage to take the cat out and pipe it, but failing that what else could the problem be?

 

Thanks in anticipation

[FROSTYBALLS]

Taking the cat out may mean it will fail the MOT

[MrBenjaminHDM]

Just now, FROSTYBALLS said:

Taking the cat out may mean it will fail the MOT

Yeah I'm aware of that thanks, need to find out if that is the problem, if it isn't it can go back on.

[lilpopjim]

Any strange noises when you start to loose power? Most notable whooshing etc

On the second graph there's a notable dip in boost when you start to hit 3750 RPM. Its also when you start to hit peak boost in that range as well. My first guess would be a fault wastegate not holding pressure as it stops right around 16psi so that would be the first thing i check.

By looking at this graph - https://goo.gl/lpqmHH - you can see that peak torque is around 2600 RPM - 3000 RPM so there's no reason to go over that to be honest, unless you're trying to get a top speed on the car!

[MrBenjaminHDM]

Thanks for your input. There's no unusual noises you can just feel the car hesitate. These graphs don't best represent this, it's more noticeable around 2500rpm. The boost starts to pull around 2000 then it pauses until just past 2500 when it kicks again. 

 

I'm having the cat looked at and the turbo checked and cleaned and should have it back tomorrow. The biggest concern from the chap doing the remap is the possibility of carbon buildup due to the Tunit over fueling, as you're all probably aware remaps have only just become available hence my decision to get the tunit.

I've heard of VGTs getting sticky from soot before which might explain the inconsistency as the vanes are struggling to adjust.

When I get the car back, if it's no different I'll record more data and come back.

I really appreciate the help, seems like a friendly community here!

[Heidfirst]

It is only very recently that anybody has been able to put a new map on these (Denso's ECU encryption was very good) - I don't think that there is much experience/knowledge etc. yet & they are still feeling their way as to what works.

[MrBenjaminHDM]

Yes I agree that it is still early days for us. He has said he's done around 30 Toyota vehicles with Denso ECUs in the last couple of months some of which are 1AD-FTV engines and mine doesn't behave as expected.

[lilpopjim]

I didn't realise these engines had VGTs.

That could be your issue, the over fuelling that is. Modern diesels are so sensitive to carbon build up these days.. especially with the EGR and strict emissions..

Hopefully it just just clogged vanes on the turbine and you'll get the car back tomorrow all well and true! 

If the vanes were blocked though, you shouldn't be getting the boost you're getting let alone the sudden drop and hesitance of the engine. If you're using a bluetooth OBD2 thingy, i'd graph your fuel pressure seeing it's essentially the burning of the fuel which drives the turbo etc. If you're getting a drop in boost without the audible sound of the waste gate opening then you've probably got low fuel pressure. Could mean a rather crappy map to be fair. Like you said; it's not behaving as expected.

[MrBenjaminHDM]

Garrett GT1749V turbo, same turbo as a lot of Audi, VW, Ford etc.

Car is ready for me to pick up later on today, fingers crossed.
I will collect all that info if it's no better and I'll be back in touch with the remap company straight away!

Thanks again.

[MrBenjaminHDM]

Got the car back and the issue still exists.

I must admit however at around peak power it doesn't half kick! I've been using Torque OBD and although it's Torque and Horsepower figures are superficial and only a guess it's gone from 122 with the Tunit to 145 with the remap and now 165 without the cat not to mention how much quicker it spools up. Turbo was looked at and it was clean and actuating. The next step as @lilpopjim said is fuel system. as per the graphs below fuel rail pressure drops with the boost but which is causing which? It has been suggested the tank, pump and filter are checked for buildup of crud. Service is due in the coming months and the fuel filer is due

The other point was that the issue didn't exist with the Tunit, however that was spoofing the rail into more pressure anyway which would push past the possible blockages.

Is there anything else to be suggested or do you think I'm looking in the right places here?

Thanks

[lilpopjim]

Oh that's cool. Must be a good Turbo then! I wonder if I have the same turbo on my 2.2. Probably will to be honest!

I use Torque Pro. Brilliant software... works great.

As for the fuel preasure I can't put a penny on that.. I had a similar problem with my very first car (Corsa C 1.3 CDTI). It was completely bone stock as well.. I do remember switching the paper filter which helped keep the preasure up.

You seem to be looking in the right places; like you said you probably have crud in the lines or in the filter basket; probably best to change the filter too.. you could also just remove the fuel filter and empty the whole thing out.. remove the sensor as well to drain all the water. Should only take you 30 minutes st the max!

 

[Devon Aygo]

The most likely source of sudden changes in fuel pressure is a sticking/failing suction control valve, cleaning it may give a temporary fix but there is a modified SCV Valve available ( Part # 04226-26020 ). Bare in mind increased turbo boost goes hand in hand with increased fuel pressure your SCV may be struggling to cope . -

[lilpopjim]

Good point Aygo. I've heard of that valve causing problems before.

[MrBenjaminHDM]

I would imagine the 2.2 has a bigger turbo, not done much reading into the 180 but I've heard you can get them to 250bhp fairly easily.

 

I'll definitely look into that SCV, if cleaning it will temporarily fix it that will narrow it down significantly. Thanks chaps.

Would you mind pointing me in the right direction @Devon Aygo? I believe its only a couple of bolts but where is the fuel pump? Its not going to be messy is it?

[lilpopjim]

I found a tutorial after a quick google search. 

 

[MrBenjaminHDM]

That engine seems to have a different layout to mine. However upon actually looking at my engine it looks to be stupidly simple. Am I right in thinking the part highlighted in the image could be the culprit? 

 

[lilpopjim]

That looks exactly the same size as the part in the video i linked. Probably is the SCV! Looks like one.. 

Wouldn't change it in the rain though :P

[MrBenjaminHDM]

Just now, lilpopjim said:

That looks exactly the same size as the part in the video i linked. Probably is the SCV! Looks like one.. 

Wouldn't change it in the rain though :P

Just having a look haha, dipped out from the office to find it 

[lilpopjim]

Haha that's the spirit

[MrBenjaminHDM]

Me and my army of mechanics have been baffled for too long! keeps me up at night... 

[TomdeGuerre]

So your car only has the single SCV (earlier) engine.  

[MrBenjaminHDM]

It's a 2007 Auris 2.0 D4D 1AD-FTV I believe. No DPF

I've not had any trouble starting it in the recent below 0 weather like most people with SCV issues.

[TomdeGuerre]

SCV's don't only give trouble for cold starting, like Devon Aygo advised you it/they can also give other trouble.

http://www.toyotaownersclub.com/forums/topic/170686-cold-start-valve-suction-control-valve/#comment-1402295  and other links

[MrBenjaminHDM]

I'll definitely be trying to clean the existing valve and then looking into replacing it if it works. The modified valve seems quite difficult to come by and expensive anywhere I've found it. The original valve is available from a lot of places for around £90 whereas the revised valve is more like £360!

Can either @TomdeGuerreor @Devon Aygo advise what the ECU changes are for the modified valve? Having had a remap done from a third party I would've thought anything Toyota would do might muddle things up. If it's an adjustment to fuel pressure I'm sure the remap company wouldn't have a problem making that change. Is it simply a case of the new valve allows more fuel pressure or is it just engine start fuel pressure that is adjusted?

Thanks in advance.

[TomdeGuerre]

It would need to be Devon Aygo to answer you about the Toyota software update, Ben