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Matt, Engineer
Category: Car
Satisfied Customers: 20374
Experience:  Honors degree in Mechanical Engineering, worked 8 years as a Formula 1 engine engineer.
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TD5..Lacks power and sluggish..turbo

Customer Question

Defender TD5. Lacks power and sluggish. Massive turbo lag below +-2600rpm. No black or blue smoke. No excessive oil consumption. No excessive wear on turbo spindle (shaft). Air hoses appear good. Injector harness replaced +- 6000km back. No missing. Where can I look next?
Submitted: 7 years ago.
Category: Car
Expert:  Matt replied 7 years ago.
The first thing to do really is to get a diagnostic check done, this should show a fault code if you have failed sensor or lack of boost. Also you could fit a turbo boost gauge to show what your're actually getting, potentially if the wastegate is stuck then as soon as the turbo boosts up over 20psi the ECU will shut things down and put the car into limp home.

The car should be boosting up over 1 bar by 1800Rpm

Its worth trying a reset ( disconnect battery for 10mins) to clear any fault codes and get the car out of any limp home setting.

Also worth changing the fuel filter if thats not been done in recent months
Matt and 5 other Car Specialists are ready to help you
Customer: replied 7 years ago.

Thanks for the tip. Unfortunately I'm about 250kms from the nearest diagnostic test facility. On checking after I posted the query I found the wastegate stuck. I freed it off and tested vehicle under load. No real improvement. Once up to speed, at about 3000rpm, I can maintain a speed of about 110km/hr. Under load, uphill, down to second gear at times. Fuel filter changed (hopefully) about 6000km ago at service. I'll replace anyway.


I'll try the "reset" route. Could it not possibly be the fly-by-wire throttle mechanism - dusty/dirty?


Expert:  Matt replied 7 years ago.
As the vehicle has ben laid up a while its worth checking the conditon of the small rubber pipes from the inlet manifold to the wastegate valve and check the rest of the intake system for any loose hose clips, split hose etc.
I doubt theres any problem with the throttle mech as its all done from the sensor on the accelerator pedal which then controls the injectors.
It may be worth unplugging and checking the pedal sensor for any dirty or recessed pins.

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