slugish td4

Hi all and thanks in advance. i have a td4 and last week the turbo went i took it to my local garage for repair and recieved it back today. the garage said that the turbo had not distroyed itself and the bearing housings were in good condition so it went for refurb. he also said that he had replaced the maf sensor because the car lacked power and it could have had a part to play in the failure of the turbo.firstly is this true ? . second when i drove the car back from the garage it had less power than what it went in with is there a reason for this ?

would be looking at the MAF sensor. I've a job to see how the MAF sensor could affect the turbo. If you do a search for roverron, or tuning diesels, there is lots of information about the MAF. It is in relation to using a synergy tuning box, but it does explain the MAF problem.

In the first instance, I would try unplugging the MAF and seeing how it runs then. If it runs better, the MAF is u/s or the wrong one.

would also check the crankcase breather filter while you've got the cover off, as they are known to cause problems with the oil pressure, which will affect the turbo bearings.

good luck

All sounds suspicious to me. Turbo failures or pretty much unheard of on td4s.
Maf sensor definitely won't cause the turbo to fail but if it's dramatically underfueling it does tend to delay spool-up by a couple of hundred rpm.

As OP says start by unplugging the maf sensor and roadtest without it. Chances are you have a poor quality replacement that shouldn't be accepted.

jabajaws said:

Hi all and thanks in advance. i have a td4 and last week the turbo went i took it to my local garage for repair and recieved it back today. the garage said that the turbo had not distroyed itself and the bearing housings were in good condition so it went for refurb. he also said that he had replaced the maf sensor because the car lacked power and it could have had a part to play in the failure of the turbo.firstly is this true ? . second when i drove the car back from the garage it had less power than what it went in with is there a reason for this ?

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What makes you say that the turbo failed? What were the symptoms?

i was driving down the road there was a clunk and then it sounded like a load of ball bearings going under the car then no power and engine managment light came on. he showed me the turbo and there was no vanes in one side. i have talked to some other people that as said the same as you guys about the maf sensor which as pxxxsed me of some what. it is going back in on tues for them to try and sort it out. would you have any nice questions for me to ask them ???. and have you any idea why i am not getting no power. i can ear the turbo and it is there at the bottom end say upto 2000rpm but its as flat as a fart there after as thoe there isnt a turbo. The only thing i cannot get my head around is it run fine before i took it in. now with a refurbed torbo and a maf sensor it is shxt 0 - 60 in 3hrs. also i did change the crankcase breather 6 months ago, at least thats done right lol

Your posts are confusing, you said the turbo was not destroyed then you say he showed you a turbo with (if i understand you) a broken turbine?
Is there any explanation as to how that has occurred?

The maf sensor plays a major part in fueling strategy below 2000rpm but doesn't have a great effect above this as the turbo takes over so from what you're saying now the maf could be OK.

They need to be looking at why the engine is not boosting as it should from 1750-1800rpm upward. It could be the boost control solenoid, it's vacuum piping or the MAP sensor. Funny how these things were working alright before the original fault though.
That then leaves the main thing they have changed, an issue with the turbo itself.

thank you for your reply i will take this info with me on tues. just one more thing i was driving to work last night trying to get up a hill i normaly fly up in fift i was in third gear at 3000 rpm and the engine worning light came on will this give them a diagnostic of the fault ? .

i all just a update the garage as had the landy for two days now i have just come off the phone and he says he is scratching is head now. he as tried all that you guys have said and even had the turbo back off to test. anyone any more ideas ??

jabajaws said:

i all just a update the garage as had the landy for two days now i have just come off the phone and he says he is scratching is head now. he as tried all that you guys have said and even had the turbo back off to test. anyone any more ideas ??

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Only questions I'm afraid....
Did they read the fault codes in the ecu?
Could they see the turbo control rod moving when they rev the engine which would at least show that the control solenoid is connected OK, has a vacuum supply and is working?
When you drive the car is the top speed limited to 70ish?

ok they have fit a new control solenoid and new mas sensor they assure me that the turbo is ok and the control rod moving and you would be lookie if the car reached 70mph. as in the above post they have fit a bosch maf sensor. now this is starting to cost a small fortune and its now getting to the stage of is it worth it. any help would be apprecaited

jabajaws said:

ok they have fit a new control solenoid and new mas sensor they assure me that the turbo is ok and the control rod moving and you would be lookie if the car reached 70mph. as in the above post they have fit a bosch maf sensor. now this is starting to cost a small fortune and its now getting to the stage of is it worth it. any help would be apprecaited

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and the fault codes ??

the fault code was the turbo boost valve. he is saying it is flat as a fart on the bottom end, and just to make sure it isnt the maf sensor he fitted the one from is landy and still the same.

The other thing that affects performance during boost is the MAP sensor as mentioned in an earlier post.
It's signal is used with others to calculate fuel quantity when the turbo boost increases the air flow into the engine. They should be able to read its signal with diagnostics that can read live data. If it's faulty and it's output is incorrect then fuelling will be incorrect.

It becoming guessing game here but they have the benefit of having the vehicle they really shouldn't be guessing and wasting your hard earned cash by just throwing new parts on.

thanks chaser it would appear that they have exhausted the sensor avenue, i spoke to them a hour ago and they have put a new map sensor in which as made a significant improvement. but he said he needed to make sure it was ok and he wouldnt be charging for is 2 days work or the boost controller or the map sensor . i wouldnt of paid anyway.

hi guys just a update. i have just recieved may landy back and its back to what it was before the turbo went he said it was a duff maf sensor.

ffs, all round the houses and back to what was suggested in the first place. makes me wonder where all these differing symptoms and fault codes come from? find a different garage next time!

chaser i think you are right. and to be honest if i had a ramp or a pit i would of done it myself lol easy for me to say that now. But on a more serious note i have noticed that its off like a rocket on the bottem end but a bit sluggish at the top dont get me wrong it does get to the tone but not like it used too, could that be a set up issue ??

to be fair they're not known to be fast. you would have to compare it with another td4, it could be that it's quite normal.