ZT-T Diesel with no Turbo boost under 2200rpm - Help Please!

[malbarnett]

Hi there,

I drive a ZT-T Diesel (130 bhp) round the M25 on a daily basis and have just come across a problem.

The car has been running fine up until yesterday when cruising along at 70 on the M25 I started to struggle for power up a sligth hill. The car in all gears has no turbo power under 2200 rpm. From 2200 rpm onwards, full turbo is available and she flies.

I haven't had any dash lights come on. This happened in heavy rain and therefore checked the usual air filter etc. with no joy.

Has anyone else had this issue? Any help is gratefully appreciated!

Thanks! Malcolm

[JohnDotCom]

Turbo doesn't come in till around the 1800RPM mark, so you wouldn't have much if any Turbo function.
More likely a MAF problem or
Water in the Plenum chambers.

[malbarnett]

Hi there,

Thanks for the response! I had a bit more of a play this morning re the symptoms. It seems ok in first and second although not ballistic. (I'm not sure however if I'm now trying to find fault) Third, fourth and fifth are however terrible without question.

I agree about you comments of turbo intro however it's like driving a very old turbo car when there's no gradual introduction of the turbo, the car literally leaps to life after 2000-2200 rpm, before this point, it's like driving a NA diesel from the 90's.

I've checked out the intake system and it's as dry as a bone.

Any further tips would be superb!

Thanks, Malcolm

[GERFIX]

Originally Posted by malbarnett

Hi there,

Thanks for the response! I had a bit more of a play this morning re the symptoms. It seems ok in first and second although not ballistic. (I'm not sure however if I'm now trying to find fault) Third, fourth and fifth are however terrible without question.

I agree about you comments of turbo intro however it's like driving a very old turbo car when there's no gradual introduction of the turbo, the car literally leaps to life after 2000-2200 rpm, before this point, it's like driving a NA diesel from the 90's.

I've checked out the intake system and it's as dry as a bone.

Any further tips would be superb!

Thanks, Malcolm

Malcolm, try disconnecting the MAF plug and driving the car for a few miles. If the performance is much better at low revs then it would likely be an out of spec MAF sensor, as suggested by JDC.

[malbarnett]

Thanks JDC and Colin ,

I'll give this a try tonight and let you know how I get on.

Malcolm

[Roverron]

Originally Posted by malbarnett

Hi there,

I drive a ZT-T Diesel (130 bhp) round the M25 on a daily basis and have just come across a problem.

The car has been running fine up until yesterday when cruising along at 70 on the M25 I started to struggle for power up a sligth hill. The car in all gears has no turbo power under 2200 rpm. From 2200 rpm onwards, full turbo is available and she flies.

I haven't had any dash lights come on. This happened in heavy rain and therefore checked the usual air filter etc. with no joy.

Has anyone else had this issue? Any help is gratefully appreciated!

Thanks! Malcolm

Maf sensor.

More info on my website:

http://tuning-diesels.com/75Zt/R75serv.htm

and on the Mafam pages

Ron

[Jules]

Welcome to the club Mal

Yep Bet you a pint it's the MAF .
Oodles on here about the subject and of course Ron's the Master

[BigRuss]

Definately sounds like the maf, recommend looking at Ron's site for info and solutions.
Best to avoid cheap maf's on e-bay which can be dubious quality.

Russ

[malbarnett]

Ok, bad news I'm afraid. The MAF sensor looked imaculate, gave it a clean anyhow. Then swapped it with another generously loaned sensor and no difference.

Next step is to try and pressurise the intake system looking for leaks.

Any other thoughts?

Malcolm

ps thanks for the welcome!

[Roverron]

Originally Posted by malbarnett

Ok, bad news I'm afraid. The MAF sensor looked imaculate, gave it a clean anyhow. Then swapped it with another generously loaned sensor and no difference.

Next step is to try and pressurise the intake system looking for leaks.

Any other thoughts?

Malcolm

ps thanks for the welcome!

Remove and clean the egr valve in case its leaking.

Ron