No boost below 2000rpm 2,5DCI 126kW m/t with DPF

[user 50654]

Hello,
I have come to the end of my knowledge here. I have the 2,5DCI m/t with DPF engine. Once I get below 2000rpm, it makes almost no power. Also, when I take off, I need to be careful with the clutch and make sure I press the gas enough, otherwise it stalls easilly. Once I get above 2000rpm, the car comes alive and rockets all the way to the limiter. I can also see live data from the ECU and see that it makes almost no boost on low rpm. Fuel pressure is good.
The things, that were changed in recent past:
EGR, SCV, turbo regulation valve, fuel+air+oil filter, MAF sensor, turbo itself, timing chain kit. Vacuum lines are tight as well as turbo hoses with intercooler. I have also checked the exhaust whether its not blocked.
No CEL codes. No black smoke (could the DPF catch it all maybe?)

No idea what to do now..Thanks alot for any advice

 

[Chapster]

I currently have an issue with non-existent boost at lower RPM but when it eventually comes on I can hit 20psi no problem.
If you have a similar issue - and you have already replaced the turbo and boost control solenoid - your issue could be inadequate vacuum.
Or at least that is one of the things I will be investigating next!
Others much wiser than me may have other recommendations.

 

[user 50654]

Got more updates. I had the injectors tested and remanufactured with the results below. Unfortunately not ideal results,will get in touch with them on Monday. Now the car no longer wants to stall on take off, but the power is still not there, maybe a bit worse now.
I also sometimes get the p0135 o2 heater problem, don't know if it can have some relation to power delivery.
I have measured the vacuum, don't remember the value, but it was good.

Wow, this is really a headache.

 

[irie]

Hello,
I have come to the end of my knowledge here. I have the 2,5DCI m/t with DPF engine. Once I get below 2000rpm, it makes almost no power. Also, when I take off, I need to be careful with the clutch and make sure I press the gas enough, otherwise it stalls easilly. Once I get above 2000rpm, the car comes alive and rockets all the way to the limiter. I can also see live data from the ECU and see that it makes almost no boost on low rpm. Fuel pressure is good.
The things, that were changed in recent past:
EGR, SCV, turbo regulation valve, fuel+air+oil filter, MAF sensor, turbo itself, timing chain kit. Vacuum lines are tight as well as turbo hoses with intercooler. I have also checked the exhaust whether its not blocked.
No CEL codes. No black smoke (could the DPF catch it all maybe?)

No idea what to do now..Thanks alot for any advice

Having the same symptoms on mine. I’m also out of ideas.
Are you having trouble with cruise control? Heard some people solved the no boost by swapping the neutral position sensor.
See if it’s acting accordingly on your obd tool.
Let me know if you solve it. Would love to solve this myself.

 

[Old.Tony]

I'd disconnect the vacuum hose from the BCS and apply a small amount of vacuum to that hose. If the vacuum diminishes over a short period, you might have a leaking brake booster (which uses the same vacuum system). Braking performance may be affected - although if it happened gradually you might not have noticed it happening, it'll just be a case of pressing the pedal harder to stop the car.

Very rarely we've seen damage to the turbocharger actuator (the gold piece on the turbo that the vac hose connects to). It's just a rubber diaphragm inside, and if it's damaged it will also produce similar results - test this in the same way.

 

[manhnguyen]

Hello,
I have come to the end of my knowledge here. I have the 2,5DCI m/t with DPF engine. Once I get below 2000rpm, it makes almost no power. Also, when I take off, I need to be careful with the clutch and make sure I press the gas enough, otherwise it stalls easilly. Once I get above 2000rpm, the car comes alive and rockets all the way to the limiter. I can also see live data from the ECU and see that it makes almost no boost on low rpm. Fuel pressure is good.
The things, that were changed in recent past:
EGR, SCV, turbo regulation valve, fuel+air+oil filter, MAF sensor, turbo itself, timing chain kit. Vacuum lines are tight as well as turbo hoses with intercooler. I have also checked the exhaust whether its not blocked.
No CEL codes. No black smoke (could the DPF catch it all maybe?)

No idea what to do now..Thanks alot for any advice

My car has the problem same your car too. Do you find to solution for no boost on low rpm. Please show me. Thanks

 

[Chapster]

Hi Manh, what have you tested or tried already to get to the bottom of your problem?

 

[manhnguyen]

Hi Manh, what have you tested or tried already to get to the bottom of your problem?

I checked the fuel system including injectors and high pressure pump, turbo, carburetor system. All without mistakes, the car moving on the road saw slow acceleration from 700-2000 rpm, when the engine rpm was above 2000 rpm, it improved a little. Climbing vehicles show very weak performance, especially when starting on a slope even with the terrain on a normal single-wheel drive vehicle.

 

[Old.Tony]

I checked the fuel system including injectors and high pressure pump, turbo, carburetor system. All without mistakes, the car moving on the road saw slow acceleration from 700-2000 rpm, when the engine rpm was above 2000 rpm, it improved a little. Climbing vehicles show very weak performance, especially when starting on a slope even with the terrain on a normal single-wheel drive vehicle.

Have you checked the boost pressure during acceleration?