EGR delete on V9X

604 Views 30 Replies 3 Participants Last post by Labsy, 5 d ago

Labsy

Discussion Starter · 2 mo ago

Hi,

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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Lukavara

· #2 · 2 mo ago

No experience on Nissans (yet), but, on VWs, EGR delete goes hand in hand with DPF delete, so I'd imagine it'd be similar.

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landmannnn

· #3 · 2 mo ago

Blank it to see what happens.

I can't remember - did you check the boost control solenoid?

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Labsy

Discussion Starter · #4 · 2 mo ago

landmannnn said:
Blank it to see what happens.

I can't remember - did you check the boost control solenoid?

Hey, thank you for reminder! I forgot about boost solenoid valve.
I guess these are the two, working in conjunction. Is it some method easy to check their functionality?

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Labsy

Discussion Starter · #5 · 2 mo ago

Lukavara said:
No experience on Nissans (yet), but, on VWs, EGR delete goes hand in hand with DPF delete, so I'd imagine it'd be similar.

I read a lot about some blanking plate with at least 8mm hole, so to allow some minimum amount of gasses to pass throu to avoid Engine light and DTC code. But I guess this could be overcome by ECU deleting EGR, just like you said for DPF delete.

One other thing...I am wrote gas flow through EGR, all from exhaust manifold right before Turbo, and all way through EGR cooler, EGR valve to intake manifold, where it mixes with fresh air from intercooler. From my logical point of view it would be ideal to blank EGR gasses right at source, so to avoid sooth to accumulate all over EGR system. But I guess this part of exhaust manifold/turbocharger is tightly squeezed between engine and firewall, so it is almost impossible to reach without dissasembling half of the vehicle.

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landmannnn

· #6 · 2 mo ago

Labsy said:
Hey, thank you for reminder! I forgot about boost solenoid valve.
I guess these are the two, working in conjunction. Is it some method easy to check their functionality?
View attachment 67249

Yes, it is number 1. I have heard they can fail, not really sure how to check it.

landmannnn

· #7 · 2 mo ago

Labsy said:
I read a lot about some blanking plate with at least 8mm hole, so to allow some minimum amount of gasses to pass throu to avoid Engine light and DTC code. But I guess this could be overcome by ECU deleting EGR, just like you said for DPF delete.

One other thing...I am wrote gas flow through EGR, all from exhaust manifold right before Turbo, and all way through EGR cooler, EGR valve to intake manifold, where it mixes with fresh air from intercooler. From my logical point of view it would be ideal to blank EGR gasses right at source, so to avoid sooth to accumulate all over EGR system. But I guess this part of exhaust manifold/turbocharger is tightly squeezed between engine and firewall, so it is almost impossible to reach without dissasembling half of the vehicle.
View attachment 67250

They say it does a 8mm hole drilling to prevent a fault code.

It would probably be a good idea to disconnect the EGR and see if it is blocked up.

Reactions: 1

Labsy

Discussion Starter · #8 · 1 mo ago (Edited)

2

landmannnn said:
Yes, it is number 1. I have heard they can fail, not really sure how to check it.

Well, today I did some diagnostic on vacuum lines using simple syringe method (plug it extended to vacuum hose and you can see how it squeezes) and found out, that I probably do not have any vacuum leak, as it is simmilary strong on all check points, BUT it looks like Turbo boost solenoid valve (number (1) on top most picture here) is always OPEN and does not close after voltage is applied. I tried to took it apart, but solenoid part is sealed so I will just buy new.

Now, I am wondering, whther I should use the same look, or the "new" look:

I have this one inside, part number: 14956BC41A
NOTE: My "measurement" showed, that output vacuum is even at OPENED state some 80% reduced in volume/strength. One more reason to think about obtaining new design...

Now, some catalog I browsed says:
Replaced By: 149566215R
...which looks like this:

What do you say? Should I go with newer "replaced by" part, or should I stick to the old one, which I have now?

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landmannnn

· #9 · 1 mo ago (Edited)

Interesting, it looks like the same boost control solenoid (turbo control valve, turbo pressure converter) was fitted to most Renault engines - Mercedes to Nissan to Dacia.

I think they are a simple on off switch controlled by the ECU, pulsing up to several hundred times per second. So I don't suppose it is that important which one as long as the electrical connectors are the same

Does yours buzz quite loudly? I know mine does, not sure if it is supposed to be like that.

The reason I suggested the turbo control solenoid is that it sounds like your turbo isn't being activated sometimes. Maybe your old valve is sticking open or shut intermittently? I would give a squirt of lubricant through one of the connections to see if that makes a difference.

landmannnn

· #10 · 1 mo ago

I took this off a Renault forum, it sounds similar to yours (their spelling mistakes)

The Turbo pressure solenoide has a rubber diaphragm in it that can perforate or split with wear. It works on air suction from the intake manifold and if it fails it basically stops sending a variable voltage signal to the ecu. The car does not stop revving fully or go into limp mode if this solenoide fails, it just does not pull as hard or accelerate as quickly as it should.

Reactions: 1

Labsy

Discussion Starter · #11 · 1 mo ago

Thank you very much for this. In fact, I thought it operates in reverse mode - opening vacuum valve on electrical input, which would cause turbo vanes to move from "idle" position to normal "power boost" position.
But according to your excerpt from Renault forum, it operates just reverse - getting vacuum (from turbo?) and converting it to electrical pulses, so ECU knows what turbo is doing. And from what I saw when I disassembled it today, it is really more likely it has vacuum-to-electric conversion function.

So I am purchasing it, not so expensive (some 50 EUR) and will report back with results.

Thanx, Landmannnn

UPDATE: Looks like it has both functions:

The solenoid valve is a plastic block consisting of an electromagnetic coil and an air valve. It has two functions:

– Electrical function. The engine ECU sends an electrical impulse to an integrated coil creating an electromagnetic field that activates a core (or spool). As it moves, it opens the pneumatic circuit and controls the wastegate.

– Pneumatic function. The air valve, connected on one side to a vacuum source (vacuum pump, also used for braking assistance), controls the wastegate via a rubber tube. When there is a vacuum in the system, the valve is closed, and the turbo is driven. Thus, in the event of accidental vacuum suppression, the wastegate opens, neutralizing the turbocharger.

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landmannnn

· #12 · 1 mo ago

I think you are right. I think I might buy one too, that loud buzzing that mine makes doesn't seem right.

Labsy

Discussion Starter · #13 · 1 mo ago

Some update:
Today I changed the Boost Solenoid Valve with OEM one, which is exactly as my old. I also tested Turbo Boost actuator, which can actually be seen on this V9X machine. It looks like it functions like this:

when engine is OFF, boost actuator rod is parked in position towards cabine/back of engine bay
when engine is IDLING, the turbo boost solenoid valve OPENS and forwards vacuum from vacuum pump to turbo boost actuator, which then moves some 2 cm towards front of the engine. You can also hear light turbo whistling. TEST HERE: pull vacuum tube off the turbo boost actuator and you should see actuator rod move and you should also hear turbo lowering revs and wining sound vanishing (see video below)
when you give it some gas, I guess either boost solenoid valve should CLOSE, but I do not know whether this happens instantly over 1000 rpm, or gradually on command from ECU and depending on driving conditions.

Short video on this test procedure, easy:

Labsy

Discussion Starter · #14 · 1 mo ago

landmannnn said:
I think you are right. I think I might buy one too, that loud buzzing that mine makes doesn't seem right.

Now as you say, I remember hearing buzzing sound some month or so ago from under my hood, too. Mybe it was Boost Control Valve dying?

Regarding my initial problem, I am still struggling with the issue - when I give it some juice, vehicle falls into limp mode, throwing P0235 code. I can drive whole day, even faster like 130 on highway, but if I do not exagerate on gas pedal, it will be fine, But as soon as I push it under load, especially in low revs to black smoke, limp mode kicks in with above code.

What I found in manual, what's the logic behind this code P0235. At least one of these must be true:

ECM detects open circuit of turbocharger boost sensor circuit for 0.4 second or more.
ECM detects short circuit to power supply of turbocharger boost sensor circuit for 0.4 second or more.
ECM detects short circuit to ground of turbochargerboost sensor circuit for 0.4 second or more.
Difference of turbocharger boost sensor value and barometric pressure sensor value is 160 hPa or less for 2 seconds or more when ignition switch ON.
Difference of turbocharger boost sensor value and barometric pressure sensor value is 200 hPa or less for 10 seconds or more while running the engine at idle speed

In my case (1), (2) and (3) simply cannot be true, because code does not trigger when idling or standstil, even not with light driving. (4) is talking about comparing barometric pressure when engine is not runing, only ingition swithc is ON, to this rules it out, and (5) says at idle speed, which also does not apply in my case.

Might it be loads of oil in intercooler, messing with turbo boost sensor?
Or chiptuning...but this was done 1 year ago and no problems until now.

BTW... after all my tests with turbo actuator rod and replacing Boost Solenoid Valve, turbo exhaling is noticeably louder. Almost like there was no air filter, it is so loud...but maybe it is how it supposed to sound?

Need some brainstorming...ideas welcome.

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landmannnn

· #15 · 1 mo ago

On the boost control solenoid, if I run the engine, turn it off and then turn the ignition key on again without starting the engine, the BCS buzzes like mad, does yours do that?

The code is saying something wrong with the boost, so if not the BCS then it will be either a faulty boost sensor or an air leak in the intercooler... Probably!

Maybe worth replacing the boost sensor? I haven't looked for a price, hopefully not too expensive.

Remaps or tuning chips have nearly always caused problems on the V6. Saying that the normal remap or chip tuning is to fool the ECU and throw in extra fuel, I don't think that will cause the boost issue.

Labsy

Discussion Starter · #16 · 1 mo ago

landmannnn said:
On the boost control solenoid, if I run the engine, turn it off and then turn the ignition key on again without starting the engine, the BCS buzzes like mad, does yours do that?

My previous BCS did exactly that!

Regarding other things...tomorrow I will replace Turbo Boost sensor and clean intercooler, however I am not sure yet about what method to take, as I do not have smoke generator. Maybe I burn some indian smelly sticks

Reactions: 1

Labsy

Discussion Starter · #17 · 23 d ago

Update:

Today I got new OBD2 tester, pulls out all possible parameters. Worth the money (88 EUR with 1 year subscription). But when I wanted to perform some twsts...nada, battery dead.
Oh, it was dying all winter long, so I went spending some beer budget and bought new 95Ah one.

Started the vehicle, connected tester with eye on all turbo parameters and went some crazy rounds, pedal to the metal. But no DTC, no limp mode.

Will do some more crazy rounds tomorrow, but hey, could it be bad battery causing all my troubles and repetitive P0235 code?

landmannnn

· #18 · 23 d ago

Crazy if that is the solution. But yes, a bad battery can upset the various ECUs.

Labsy

Discussion Starter · #19 · 22 d ago

Update 2:
No, unfortunatelly it was not bad battery fault

I did few test runs and hit limp mode and P0235 code every time under same conditions:
RPM: 3250
Fuel rail pressure: 1600 bar
TC boost: 2.4 bar/35 psi (atmosferic pressure deducted already)
Torque: 530 Nm/390 ft lbs

Isn't that 35 psi a bit too high?
Might it be chiptuning, which was functioning just fine for past year?
OR might it be something with Turbo actuator, which I suspect, because ever since I have this P0235 code, I can hear turbo inhaling air more loudly, simmilar sound as if I would took off air filter assembly and put sport filter on. Actuator rod is moving some 2-3 centimeters when giving it some gas, but what if it is detached internally maybe, and is producing too much boost all the time? Dunno if this is possible, but I am out of ideas.

landmannnn

· #20 · 22 d ago

35 psi is way too high which is why you are getting the code.
I think the tuning chip could easily be the cause, I would agree that the only other likely issue is the turbo vanes getting stuck in the wrong position.

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