Suzuki K10C (tgdi) had parts issues but keeps losing boost pressure

Superflan

Superflan

Joined
Apr 28, 2015
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Location
Reunion Island
Hi,

I'm having a quite unfortunate issue with the Suzuki Vitara MY2019 BoosterJet 1.0. Car was bought as new, and I always did regular oil and filter changes, with shortened OCIs, as well as for other filters, and spark plugs.

first signs of something wrong were around 50000km only when I would do some WOT accelerations, a "GPF malfunction" would pop on the multifunction screen in the middle on combination meter, but would disappear. Nothing more. (sorry I will continue the post after, I had to edit this one due to a miss tap on "save")
 
eww Gasoline particulate filter.. ew .ew ew. (will wait for the rest of your post to pop up after editing)
 
then, it started slowly losing power really noticably at 100000km or something. When I finally got into trying to understand what was wrong, and proceeded to remove the hoses connecting the GPF differential pressure sensor to the exhaust, I found out that the plastic nipples on the sensor broke off and that the sensor might as well be shot from a long time ago, preventing proper GPF cleaning operation.
I replaced the sensor and the GPF malfunction message definitely didn't came back even at WOT.

But the lost power... never came back. at this moment I could have 7 psi boost pressure at WOT. I didn't pursue further diagnosis, until wife complained that the engine was doing a big loud rattle and was lacking more and more power. 141000km: after diagnosing, and trying to plug the diverter valve closed to see if I can have boost again, I bought a younger fuel high pressure fuel pump from an European used parts suppliers, pulled from a 30000km car, since it's known to be an issue and I had every symptom of it failing. it solved the noise issue, and gained a little bit of power, but it's still lacking.

Now, boost pressure at WOT is 4 psi, and I still have no DTC, no nothing, just reduced performance and low boost pressure. My electronic gas pedal position seems to be working correctly as I can rev freely on neutral.

I don't know where to start diagnosing again with my limited tools around here.
clogged exhaust? remove and test?
worn/eroded/gripping turbo wheel? remove intake and exhaust and observe?
MAP sensor? replace and retest?
dump valve not holding boost but the first plugged test was irrelevant because the fuel pump was going bad?
dump valve solenoid? test?
wastegate control broken even if the pneumatic actuator do have movement, but it could be vacuum from start and be stuck? broken solenoid? test?

What would you do? what is the most plausible or seen on TGDI engines when power is reduced and you can't have boost? Stock boost was around 15psi when it was working.
 
My Suzukis have been uber reliable. Was just driving my 2006 Grand Vitara today. Yours sounds like it has a waste gate issue prematurely dumping boost. I don't think the US ever got a turbo Suzuki.
 
I'd keep it simple and start checking the intercooler hoses very carefully for splits, especially if they are all the originals. Look particularly in the bends and where the hose clamps go.
 
If there's boost getting spilled, the air mass will be off as will the fueling.

I would undo the exhaust prior dpf and go for a run. If you get full boost, hey presto!
 
Passport1 said:
Yours sounds like it has a waste gate issue prematurely dumping boost.
Click to expand...
Ive previously put sharpie on the wastegate actuator rod to make sure it moved, and the travel looked pretty good so I thought it was a non issue. I think the wastegate would be closed only when vacuum was fed to the actuator so I didn't bother more. But I'll check there if I had to undo the GPF

Jetronic said:
I would undo the exhaust prior dpf and go for a run. If you get full boost, hey presto!
Click to expand...
there's nothing between the GPF and the turbo hot side exit flange, which points horizontally parallel to the cylinder head. Any clue how to divert those hot exhaust gas and not burn anything while I go for a 3 minutes round-trip test drive?

hpb said:
I'd keep it simple and start checking the intercooler hoses very carefully for splits, especially if they are all the originals. Look particularly in the bends and where the hose clamps go.
Click to expand...
might be something, as the engine sounds slightly louder from others perspectives. Intake noise from the leak?

I think I'll proceed to inspections on Sunday and report back. TIA
 
Are you able to read the pre-GPF pressure like you are on a diesel? That would instantly give a clue to if you're suffering with GPF blockages.
 
Bailes1992 said:
Are you able to read the pre-GPF pressure like you are on a diesel? That would instantly give a clue to if you're suffering with GPF blockages.
Click to expand...
I currently don't have access to the differential pressure reading via OBDII, but I can either measure the sensor voltage output and do calculation, or assume that the ECU knows when there's a GPF blockage because there's a dashboard message documented for that in the user manual.

Since the MAP sensor is located not far away from the turbo and some mortified intake hoses (and PCV), I can assume that it had also been cooked by heat and needs replacement anyway ?
 
Passport1 said:
My Suzukis have been uber reliable. Was just driving my 2006 Grand Vitara today. Yours sounds like it has a waste gate issue prematurely dumping boost. I don't think the US ever got a turbo Suzuki.
Click to expand...
OK while chatting with my brother, he suggested that the wastegate actuator solenoid might as well be always passing vacuum, and that's why the sharpie mark I put on the rod went away, but that wastegate might be closed at rest, as opposed to opened at rest, leading to no boost situation since vacuum might be always present.

I'll be unplugging the wastegate actuator and plugging the vacuum hose, and see what happens.
 
Did you scan the engine computer for code? The Service Engine Soon light is on only when an emissions related code is present.
 
Superflan said:
I'll be unplugging the wastegate actuator and plugging the vacuum hose, and see what happens.
Click to expand...
So, when unplugging the wastegate actuator I run like full NA. 0.6 psi when I try to move on my 100% hill as the torque converter stalls, VS 1.7 psi when the actuator is plugged, so it's doing something, but maybe the vacuum solenoid is acting up, more to that later. I'd do some schematics, as the control system is interesting to me and I'm willing to learn how this works.

KrisZ said:
I would try unplugging the MAP sensor next. My in-laws Jetta tdi had a similar issue and I eventually ended up unplugging the MAF and the boost came back on.
Click to expand...
Good suggestion, I didn't unplug MAP yet, but when trying things tonight I unplugged MAF, and it went failsafe and ran full NA again, 0.6 psi at TQ stall rate and WOT.

Marcozi said:
Did you scan the engine computer for code? The Service Engine Soon light is on only when an emissions related code is present.
Click to expand...
Yes, I have no code active or pending. It's like everything is coherent for the ECU and fault detection isn't too demanding...
 
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KrisZ said:
I would try unplugging the MAP sensor next. My in-laws Jetta tdi had a similar issue and I eventually ended up unplugging the MAF and the boost came back on.
Click to expand...
so, while unplugging the MAF made the car go NA, unplugging only the MAP was really interesting! made the car go NA, the pressure reading was 22.6 psi all time, and the auto gearbox would only shift in 3 even in manual mode. on top of that, ESP warnings, everything.
 
bypassing the vacuum switch connected to the waste gate actuator had the actuator trigger even at idle, and no improvement while driving. so, I think I'm left with:
-MAP sensor
-MAF sensor
-broken/bent/jammed waste gate
-boost leak

or more dramatic suggestions:
-seized turbo
-electronic wizardry

I think I'll inspect wastegate and more generally turbo wheels on Sunday.
 
Passport1 said:
My Suzukis have been uber reliable. Was just driving my 2006 Grand Vitara today. Yours sounds like it has a waste gate issue prematurely dumping boost. I don't think the US ever got a turbo Suzuki.
Click to expand...
Someone heard the car noises when I arrived at a car meet today and immediately mentioned "it seems you have a wastegate rattle". I googled and found a fair share of YouTube videos sounding a bit like the sounds I had that I attributed to GDI noises.

Mine sometimes goes like this: especially on upshifts or foot lift just before coasting.



Then I saw it was a common issue on IHI turbos. Definitely going to check the wastegate tomorrow!
 
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