EGR delete on V9X

602 Views 30 Replies 3 Participants Last post by  Labsy

I am struggling with performance ever since I bought my 2010 Pathy 3.0 V6 diesel. First few months it was not so obvious nor irritating, but lately it has become real struggle. I wrote about it before, but no solution.
Driving on highway at around 1200-1500 rpm or going uphill some windy road, giving it some gas does nothing but a huge ammount of soth out of exhaust, then only after flooring it it suddenly kicks in and accelerates brutally, so to speak. It is real struggle overtaking or pulling out of curves, as it has soooo much delay and smooth acceleration is not possible.
BUT this does not happen always - sometimes it just accelerates smooth as I give it some gas.

So, my hacker, who did chiptuning and DPF delete says, it is quite possibly EGR either clogged or opened all the time.
But theres no DTC.

Thinking... should I try just blanking EGR temporarily to see if any difference? And if this goes well, we can just remove it programatically later.

Any thoughts? Anyone did it on V9X engine?
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Yes, I thought the same. I don't know how to test turbo vanes in this tight space, as I cannot disassemble anything.

The only things I can check is:

1. Is actuator rod moving? YES! It moves some 2-3 cm forward when vacuum activator gives command. I guess it must have been broken some part inside, if vanes would not mowe with actuator rod.

2. Another test was with engine running and I tried to keep steady accelerator pedal to keep near 2000 and then around 3000 rpm (red line) while observing boost pressure (green line). It looks like as I was trying to keep rpms steady, turbo boost was dropping by time. Does this mean vanes are working?
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Regarding possibly too high turbo boost...could it be that maybe a bit clogged intercooler and mostly broken Turbo boost pressure sensor could interfere 1 year ago when engineer was tunning the engine? Other way I do not see a reason why and how it was working under the same boost for 1 year till now.
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I would say the turbo is working correctly as the boost drops off around 0335.
That peak just after 0330 just seems too high.

I think the boost sensor is working as you wouldn't see the reading on the graph.

As you have replaced the boost control solenoid, I think we can rule that out.

I can't remember, did you have it remapped or a tuning chip? If it is a tuning chip you could remove it.
I have it remapped. It's not easy as removing chip, but I will go back next week and let them restore original maps back.
Update after remapping ECU back to original:
Still no go :(
What it does now is only throws P0235 code at lower boost and performance, meaning earlier.

But what I noticed today when driving 200 km of highway was when going long uphill and adding a little more gas pedal, turbine starts jerking and hissing sound is heard, "hissss", like when you go off throttle, but it was like 2 times per second, hisssss, hissss, hissss, and I felt vehicle was shaking.

On the graph it can be seen after down spike, when I went off the throttle as one 18-wheeler was in front of me on uphill, then I added some gas to overtake and those shaked lines are above mentioned turbine hissing and vehicle jerking.

I guess next step is to pull out turbo and examine/repair. Anybody knows if turbo can be removed without lifting up the cabin or taking whole engine out?
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I've not done it, but engine out, cab off or drop gearbox are the only methods.
I've not done it, but engine out, cab off or drop gearbox are the only methods.
I guess engine drop would require also front diff drop, transmission drop and...geez, they could have make vehicle 5cm longer just there, inbetween turbocharger and cabine firewall :)
Going the engine route would normally be lifting the engine. Quite involved as there are several radiators that would need to come out.
The gearbox drop would seem a bit easier.

Just thinking about it, it is possible the actuator is sticking, or at least not moving freely. Can you get to actuator to see if it is free to move?
Maybe try lubricating the part you can see?
My mechanic says, it would be enough to just tilt engine a bit forwards, but a radiator or two would still need to come out. But still he said it is 2 days of work just to get turbocharger out that way.

My plan now is to disconnect 2nd catalyst converter, as there are some chances it is clogged or seized. Even more - it might be some chunks got loose and clogged muffler. So by just breaking line right after 1st catalytic converter would tell quite a lot regarding the possible issue. I would also disconnect 1st one, but it is not accessible, just like turbocharger.

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Partial success so far:

mechanic removed 2nd CAT and muffler, but he says there was no difference. But he did not took a test ride.

But what he noticed was weird ticking sound when shutting off the engine from SCV Suction Control Valve, which I just replaced few weeks ago. So he replaced it once again and no more ticking sound + no more P0235 code + no more limp mode. Yippee?
Well...not entirely. Vehicle drives like before all those problems, but now I remember what was the main reason I went with replacing SCV and TC boost sensor + cleaning intercooler in the first place - it was because I was noticing more and more turbo lag, more and more dull response to accelerator pedal and more and more smoke.
So now it is even more dull when I press gas pedal - on highway it almost feels like it does not want to go, like driving against strong winds. Yes, I can go 100, 130 and 160 kph, but accelerating is PITA. When it is near or over 2000 rpm, it pulls, with chiptuning it actually pulls brutally. But when in lower RPMs, like crusing on highway at 1100 RPM and giving it some gas, it builds up turbo boost, even goes into higher RPM, and fuel pressure raises, too...but all it does is anormous volume of black smoke.
Tried with and without chiptuning, same story.

I was nagging about this even before, very annoying to drive it up some curvy roads, as it just smokes and does not pull, unless you kick it quickly on acc pedal, or downshift manually.

So, I am thinking further:
  • Can it be turbo vanes are sticking, but thise is not reflected on actuator rod? I mean...I am looking at turbo vanes actuator rod in idle - it moves smoothly from one to other extreme position. Then I disconnect vacuum line, and it returns to off position smothly. I repeat this many times and it looks like movement is smooth. So I am wondering, if somewhere behind the actuator rod turbo vanes could still be sticking, but I would not be able to diagnose it by observing actuator rod?
  • Could it be EGR failing somewhere else, except on EGR valve? I took is apart and did EGR valve test with diagnostic tool, and it also moved smooth, opened and closed as far as I know to full extent. And it is not so dirty at all. And I cleaned it with microfibre rag and plenty of brake cleaner.
  • Or what else could be the root cause of this not-accelerating-only-smoking effect at low RPM?


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Ok, so black smoke means unburnt fuel. Two reasons - too much fuel or not enough air.

Too much fuel. What could cause this? Faulty SCV, a failing injector or the wrong information from the mass air flow sensor.

Not enough air. What could cause that? Blockages or leaks in the intake. Not enough boost from the turbo.

I can only think of 4 things that would be causing not enough boost. Blocked cat or DPF, vanes not reacting, turbo bearings binding or boost control.

As a comparison, I monitored the same settings as you on mine. The app I am using doesn't do the nice scales on the X axis, but in comparison the boost pressure immediately goes high as soon as I accelerate. It almost exactly follows the pattern of the rev and fuel pressure, unlike yours which seems a long way behind.

It seems your boost control is working ok, so it must be either blockages in the exhaust/cat/dpf or blockages in the air filter or something is sticking in the turbo.

Not sure this has helped apart from saying it is unlikely to be the EGR.
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Not sure this has helped apart from saying it is unlikely to be the EGR.
Very helpful, thanx! If I find something interesting, I'll report back. But as I cannot inspect the turbocharger, I am without significant volume of diagnostic Thanx for now.
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