M2 1.5dci 106bhp - Reconditioned Turbo - Boost Drops

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Boggy22
Posts: 4
Joined: Thu May 18, 2017 6:24 am
Currently Drives:: Megane 2 1.5dci 106bhp > 125bhp & 320nM on Dyno

M2 1.5dci 106bhp - Reconditioned Turbo - Boost Drops

Postby Boggy22 » Thu May 18, 2017 6:54 am

First of all hello to all of you, this is my first post on this forum. Sadly it's with a problem which I hope to get some help with.

About 3 weeks ago I was in an overtake, and right in the middle of it I heard a "pfffiiuuu" sound, then the car won't respond to my throttle. Luckily, I was overtaking a scooter on an empty road. I even have the moment on video from the dashcam here:

https://www.youtube.com/watch?v=VlPxBY5bX4A

At first is the moment when the turbo shaft snaps, then some extracts from the way back home, foot all the way down on the pedal with snail-like acceleration. I really thought that some intercooler hose snapped and that's where all the pressure went, but apparently the turbo shaft broke.

I had to drive 300km like that until I got home and could get the car in a service. When I arrived, the new oil put in a week ago got on the "min" level, so I"m guessing it ate about 1l of oil through the turbo. This might be important because I think that maybe my problem might be a clogged catalyst?

Anyway, after reconditioning the turbo at one of the best places around, I noticed that the car drives differently. Most importantly in first gear it doesn't have that aggressiveness (I have a remap for 5 years, it went to 125bhp/320mN measured on dyno). Also, the turbo whistles when it goes past 1.2bar. And it's not the high pitched whistle of a Renault DCI turbo that you can only hear in a range of turbo RPMs, it's lower, more like a supercharger. I also don't think that the "new" turbo is unbalanced, because as I said, the whistle is only pressure related. Might it lose pressure through some hose?

I connected my OBD reader into the car and did some tests, and what I noticed is that it has strage turbo pressure drops. After the remap, the turbo is supposed to deliver 1.54 bar of pressure on all rev range (past 2300-2500rpm when it gets enough spool of course). Here's what it's doing now:

https://www.youtube.com/watch?v=RnOCWEsCHoI

0 > 1:20 - 3rd gear acceleration, you can notice the pressure drop(I can also feel it in how the car pulls) in between 3100 - 3700rpm, then it comes back to 1.5 and stays there up until 205km/h on the dash(the speed you see is the GPS speed).
1:20 > 1:50 - 6th gear acceleration, the pressure drops between 2500 > 2800rpm this time
1:50> final - Acceleration from 3000 rpm, pressure doesn't drop anymore.

(You can also hear the whistle on the video.)

I think this is why first gear is so changed now as well, the pressure drops, and until it spools back enough it's too late because I have to shift to 2nd. For example, before the turbo incident, if I "power-started" from 2500rpm, it would pull like crazy, but if I do that now it seems like that turbo pressure isn't going into the engine and it almost dies. I have to rev it to +3000 for a decent start, but not even then it's not like before.

Here's how it pulled before the turbo problem, even with idle starts.

https://www.youtube.com/watch?v=AI9yInXqRlY

Here are some things that I thought of:

1 - Clogged cat from the oil, when I drove 300km with a broken turbo
2 - Pressure boost controller (electrovalve) malfunction? I noticed when the turbo snapped and I was checking the engine bay, that the 3 wires from the Boost Controller rubbed on the engine cover and the wires were exposed? Could they have shorted and damaged the valve? I did wrap them in electrical tape immediately but maybe it got damaged then.
3 - Wrong actuator settings on the reconditioned turbo? It's a KKK BV39 VNT turbo btw.

Any tip or suggestion would greately help!

Thanks,
Bogdan

grandadbobby
Advanced Driver
Posts: 499
Joined: Thu Feb 16, 2017 9:05 pm
Currently Drives:: megan dynamique estate 1.9dci

Re: M2 1.5dci 106bhp - Reconditioned Turbo - Boost Drops

Postby grandadbobby » Thu May 18, 2017 12:24 pm

Hi,
you say turbo re-con by good place, but who fitted it and was the actuator altered.
l don't think it should whistle and if the rest of the engine is good, the vanes can't be closed properly to give the boost on low revs.
l suspect having been re-mapped, you should take it back there for proper diagnosis, but if you want to look at this yourself, you need to check that the boost control is working properly.
You can find some information on you tube.
Good luck
Bob.

quaker@eircom.net
Learner Driver
Posts: 55
Joined: Sat Nov 29, 2008 4:22 pm
Currently Drives:: renault megane 2005 1.5dci automatic

Re: M2 1.5dci 106bhp - Reconditioned Turbo - Boost Drops

Postby quaker@eircom.net » Thu May 18, 2017 1:17 pm

Hello there......Did you find out why the turbo shaft snapped?....Did you replace both turbo oil feed pipe and turbo return oil pipe or at least check that they are not blocked.? Did you get the intercooler and the associated piping properly cleaned? Get a vacuum pump and apply vacuum pressure to the pipe that connects with the diaphram unit attached to the turbo and see does it actuate the lever rod going into the turbo and also does it hold the vacuum. rgds Maurice

Boggy22
Posts: 4
Joined: Thu May 18, 2017 6:24 am
Currently Drives:: Megane 2 1.5dci 106bhp > 125bhp & 320nM on Dyno

Re: M2 1.5dci 106bhp - Reconditioned Turbo - Boost Drops

Postby Boggy22 » Thu May 18, 2017 2:16 pm

grandadbobby wrote:Hi,
you say turbo re-con by good place, but who fitted it and was the actuator altered.
l don't think it should whistle and if the rest of the engine is good, the vanes can't be closed properly to give the boost on low revs.
l suspect having been re-mapped, you should take it back there for proper diagnosis, but if you want to look at this yourself, you need to check that the boost control is working properly.
You can find some information on you tube.
Good luck
Bob.


I have no idea what they did to the actuator. The turbo was reconditioned in one place, and mounted in a different service(where the car was taken apart).

It really shouldn't whistle, the stock one did not. Being a pressure related whistle, I think air is escaping from somewhere. Maybe the mechanic didn't secure the hoses back properly on the turbo when putting it back on...

quaker@eircom.net wrote:Hello there......Did you find out why the turbo shaft snapped?....Did you replace both turbo oil feed pipe and turbo return oil pipe or at least check that they are not blocked.? Did you get the intercooler and the associated piping properly cleaned? Get a vacuum pump and apply vacuum pressure to the pipe that connects with the diaphram unit attached to the turbo and see does it actuate the lever rod going into the turbo and also does it hold the vacuum. rgds Maurice


The exhaust props were off-centered and stuck, the intake part was ok, rotating freely. I don't know why the shaft broke, but the mechanic said that the shaft usually breaks if there isn't enough oil getting to the turbo. He said that in case of low oil pressure(a known common problem on some dCi's), the engine might be also bad and need re-segmenting. So I asked him that after he puts the new turbo back in, to check the oil pressure.

He did it but with a 0-35bar manometer and got confused by the scale, and said that the pressure is very bad. 0.5-0.7bar, barely 1 bar at 3000rpm. I did not believe this and took the pressure at another service and it's better than perfect. The manual says that K9K should have 1.2bar at idle and 3.5bar at 3000rpm. My engine has 2.2bar at idle and 4.5-5bar with throttle. It's one of the best sounding dCi's out there, I take great care of it, service it regularly and only with good parts/fluids.

I did not however check the oil lines to/from the turbo, and I don't think the mechanic did it either, but that's what I'm going to do next(at a different mechanic, that doesn't give me missed heartbeats because he can't read a lousy manometer).

I also did not clean the intercooler, I planned doing that on my own but did not have the chance so far(I need a whole day off).

I have a friend with the same engine/car/year, I think I should ask him to lend me the boost controller of his for 10-20 minutes so I can check. At least it's easily accessible.

I wonder why is it losing boost at different RPM values, that's what puzzles me.

quaker@eircom.net
Learner Driver
Posts: 55
Joined: Sat Nov 29, 2008 4:22 pm
Currently Drives:: renault megane 2005 1.5dci automatic

Re: M2 1.5dci 106bhp - Reconditioned Turbo - Boost Drops

Postby quaker@eircom.net » Fri May 19, 2017 12:13 pm

hello......Might be worth checking the turbo boost sensor.
Maurice


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