BOOST ISSUE

General Chat about the Mk1 QashQai
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Lukie86
Posts: 1
Joined: Wed Apr 13, 2022 12:43 pm
Qashqai Model: Mk.1 Qashqai - J10 (2006–2013)

Post by Lukie86 »

Hello sorry if I'm not able to explain my problem correctly my dyslexia don't help.

I have a 2008 J10 1.5dci but me and my mechanic are struggling to find out why my car is not boosting. When it's in idle it won't rev past 2k but once it heats up it will go past 3-3.5k but with no boost.

We have replaced the turbo, egr valve, maf sensor, check the cat and air filters, also have checked all components individually and everything is working as it should but it still does not want to give any boost, we also checked the timing as well and that's all ok. I believe we have checked and changed everything that we could. There was a boost fault on the car but after changing the parts there is no fault codes coming up at all. But yet the car is still not boosting if anyone has any ideas or has come across this before please let me know all suggestions will be appreciated thanks Luke.

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MikeGC
Posts: 1852
Joined: Tue Feb 07, 2017 11:50 am
Location: Stockport
Qashqai Model: Mk.3 Qashqai - J12 (2021+) New Model

Post by MikeGC »

Welcome to the forum, Luke
I’m completely non-technically mind but there are others who may be able to help

Good Luck
March '22 - J12 1.3DIG-T 160 CVT Tekna+ with all wheel drive - Pearl Black
July '19 - J11B 1.3DIG-T 160 DCT Tekna - Vivid Blue
March '17 - Qashqai J11A 1.5dci n-connecta - gunmetal
September '14 - Juke 1.5dci gunmetal ascenta premium (red accent packs)
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calnorth
Posts: 2719
Joined: Mon Feb 11, 2019 2:01 pm
Qashqai Model: Mk.2 Qashqai Facelift - J11b (2017–2021)

Post by calnorth »

This is about enabling the ECU to control the Turbo charge which relates to a number of critical inputs. The ECU matches those inputs to its internal performance map.

TBH I'm not familiar with the system and you appear to have changed many components of the system which might not be helpful. You maybe stabbing in the dark without the right system documents and procedures.

BOOST is about the ratio of Turbocharged air pressure to Atmospherics pressure at Sea Level within the inlet manifold. Boost is therefore an amplification of low pressure air that is not happening in your case. Hence the dead Boost you seem to experience...something like that anyway.

ENGINE TORQUE CONTROL

System Description
The torque structure is the system which translates the driver's request into a torque supplied by the engine. It
is required for certain functions such as the electronic stability program (ESP), the automatic gearbox or the
sequential gearbox if fitted).
Each inter-system (ESP, automatic gearbox, sequential gearbox) sends the ECM a torque request via the CAN
communication. The computer arbitrates between the inter-system torque requests and the driver's request
(comprised of the accelerator pedal or the cruise control/speed limiter function). The result of the arbitration
gives the torque setpoint.
From this torque setpoint, the computer determines the quantity of fuel to be injected (injection duration and
number of injections) and the amount of air required (turbocharging pressure and EGR rate) so that the engine
is able to provide the torque required in the best possible conditions (in terms of smooth running performance,
pollutant emissions, etc.).

The system will be governed by the sensing of air/fuel flow, temperature and pressures including EGR state and each within particular limits. Without the technical specifications to setup the system its impossible to diagnose. The DTCs if present would be useful.

Sorry to say I'm struggling to help here so my advice is very general. However, every component of the system needs to be accurately tested so that confidence can be acquired in enabling the ECU to command Boost correctly at the various states of the engine in relation to demand and load.
Mk2 Qashqai Facelift - J11b (2017–and onward)
1.6 Dig-T N-Connecta
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