Rich237

1.6 TDCi P0299 code. Were to look before stripping turbo and pipes?

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3 hours ago, Finneagle64 said:

Would the actuator not working quite right cause my boost pressure to be low at high rpm and speed though? Because my car is completely fine until i get to around 70-90mph

Have you checked you are still getting the same P0299 error code? There are also error codes for boost pressure too high, or lots of other things.

If it is still saying underboost, then it could be that the expectations of the ECU are changing as rpm rises. 70mph is only a bit over 2000rpm in 5th, so below this it may be normal for boost pressure to be below max. Then as the exhaust gas flow rises, the ECU expects a rise in boost pressure. If the actuator is sticking, or the MAP is mis-reading, then it may not be seeing this rise.

If you have Forscan, it can log realtime boost pressure, rpm, and I think actuator duty cycle. It will also show just when an error is flagged, so could pin down the event a bit.

Without diagnostics, a fault like this is really only tested by changing bits until you find a bit that cures it. There is always the worry that one of the bits changed may be faulty or wrong, and confuses the situation even more!

 

 

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On 3/16/2019 at 4:25 PM, Tdci-Peter said:

Have you checked you are still getting the same P0299 error code? There are also error codes for boost pressure too high, or lots of other things.

If it is still saying underboost, then it could be that the expectations of the ECU are changing as rpm rises. 70mph is only a bit over 2000rpm in 5th, so below this it may be normal for boost pressure to be below max. Then as the exhaust gas flow rises, the ECU expects a rise in boost pressure. If the actuator is sticking, or the MAP is mis-reading, then it may not be seeing this rise.

If you have Forscan, it can log realtime boost pressure, rpm, and I think actuator duty cycle. It will also show just when an error is flagged, so could pin down the event a bit.

Without diagnostics, a fault like this is really only tested by changing bits until you find a bit that cures it. There is always the worry that one of the bits changed may be faulty or wrong, and confuses the situation even more!

 

 

Just bought myself a bluetooth obd reader to check the engine code so i will see what it says. 

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On 3/17/2019 at 8:03 PM, Finneagle64 said:

Just bought myself a bluetooth obd reader to check the engine code so i will see what it says. 

It is still underboost p0299.

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On 3/16/2019 at 12:28 PM, Finneagle64 said:

my car is completely fine until i get to around 70-90mph (it sometimes differs) and then it will just go into limp mode and i have to stop completely and turn the car off for it to reset

P0299 is an irritating one, it took me ages to find the cause on my car, mainly because out of blind foolishness I overlooked the most obvious cause, even though it was staring me in the face. The little hose that seems to have caused it is right at the top of the engine on the 1.8! I was so sure I had looked at it that I ignored it.

P0299 just means pressure reading from the MAP is too low. It could even be a blocked air filter, that would stack up with it happening only at high rpm & power.

If the car pulls well at lower rpm, then it seems the turbo is spooling up ok. If I recall, on the 1.6 the turbo actuator rests in the max boost position, and it needs vacuum on the actuator to move it to the no boost position for idling. So it should cycle when the ignition is turned on, or when the engine starts. That is one test of the actuator & vacuum system.

Blockages anywhere in the air intake system, including intercooler, throttle valve, inlet manifold, valve passages etc, could all cause pressure drop at high airflow. So could blockages in the exhaust, like DPF or cat. The DPF pressure drop is monitored, but if your DPF system is not working or disabled, like a broken hose to the DPF DP sensor, then that could do it.

The MAP sensor on the 1.6 is near the throttle valve & dipstick, see:

 

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On 3/19/2019 at 8:03 PM, Tdci-Peter said:

P0299 is an irritating one, it took me ages to find the cause on my car, mainly because out of blind foolishness I overlooked the most obvious cause, even though it was staring me in the face. The little hose that seems to have caused it is right at the top of the engine on the 1.8! I was so sure I had looked at it that I ignored it.

P0299 just means pressure reading from the MAP is too low. It could even be a blocked air filter, that would stack up with it happening only at high rpm & power.

If the car pulls well at lower rpm, then it seems the turbo is spooling up ok. If I recall, on the 1.6 the turbo actuator rests in the max boost position, and it needs vacuum on the actuator to move it to the no boost position for idling. So it should cycle when the ignition is turned on, or when the engine starts. That is one test of the actuator & vacuum system.

Blockages anywhere in the air intake system, including intercooler, throttle valve, inlet manifold, valve passages etc, could all cause pressure drop at high airflow. So could blockages in the exhaust, like DPF or cat. The DPF pressure drop is monitored, but if your DPF system is not working or disabled, like a broken hose to the DPF DP sensor, then that could do it.

The MAP sensor on the 1.6 is near the throttle valve & dipstick, see:

 

The actuator does move slightly, when the car is off the actuator pushes out and then when the engine is on it sucks the rod coming out of it in. So im guessing it works... to some extent. Might replace it anyway and hope that jt sorts it. It makes horrible creaking noises if i push and pull it so thinking its just old and knackered

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