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 MG ZT cdti power loss 
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 Post subject: MG ZT cdti power loss
PostPosted: Fri Apr 03, 2015 8:23 pm 
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Hello all. Been on a couple of other Rover/MG forums with my problem, but as yet, no joy. :?
I'm a recent new owner of a 2003 m/y MG ZT cdti and am having trouble with a constant/intermittent power loss. I've tried disconnecting the MAF with no change, cleaned the MAP..no change. Checked the wastgate...all moving freely....cleaned the EGR and checked its operation...all ok . Also tried wriggling the wiring to each injector with the engine running...no change!
Starts well hot or cold,doesn't smoke at all, pulls away well from standstill, no misfiring...no engine check light.....just loses power after a couple of miles..can still cruise at 60 as long as there isn't an incline, but no acceleration. If I can get the revs to 4k the power cuts back in and it drives normally for a while.
Also if I stop,turn off the engine then turn back on the power returns that way too....for a little while ?
Hopefully someone on here has had the same symptoms and found the cause?
Any help would be much appreciated as I really like this car!
Cheers.Simon

Forgot to mention the fault codes;
checked fault codes and they were;
P1e30- boost control
P0500- speed sensor
P1470- boost control


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 Post subject: Re: MG ZT cdti power loss
PostPosted: Sat Apr 04, 2015 11:27 am 
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Two possibilities.

It seeing an over boost and going into a limp mode take out the boost control module and run a vac pipe directly from where the valve gets its feed to the actuator.

EGR blocked or intermittent fault
The same things happens with a lot of diesel's the EGR blocks or sticks and engine will be flat till it reaches higher revs some cars you can just cap the EGR system off with no issues and other vehicles require them to be mapped out to stop a MIL light.

Turning car of will cycle ignition taking it out of limp mode I would say it's possibly one of the above.

I'm also not sure what turbo they run is it a VNT as they can be known for the vains to stick but if it's a basic turbo then unlikely but you said you have checked actuator movement ect.

That gives you a couple of options to look at :)


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 Post subject: Re: MG ZT cdti power loss
PostPosted: Sat Apr 04, 2015 6:42 pm 
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Thanks for that. :)
EGR cleaned and polished...not sticking......disconnected the vacuum pipe from the EGR and plugged it.....still no change. :?
Oh...no variable vanes on these turbos. :)
PCV checked...all ok and clean.

It loses power no matter how I'm driving at the time...whether on a steady throttle just cruising along or putting my foot down?


Last edited by simj26 on Sat Apr 04, 2015 6:53 pm, edited 1 time in total.

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 Post subject: Re: MG ZT cdti power loss
PostPosted: Sat Apr 04, 2015 6:50 pm 
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One thing though....the longer I sit with the ignition turned on without starting the engine, the longer it takes for the problem to show itself .
Been up to a friends house where we plugged the diagnostics into his laptop three times and gone for a drive so he can see what's happening.....but every time we do that the problem doesn't appear.
The only thing we've done every time is to sit for quite a while with the ignition on while the ECU connects to his computer and he logs the previous data. :?

One more piece of information that might help.....the previous owner has fitted a non return valve between the under bonnet fuel pump and the fuel filter.....he said he fitted the non return valve to stop fuel draining back to the tank over night as it was making it difficult to start in the morning?
However...I've just tried it with the non return valve removed......no change! :cry:


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 Post subject: Re: MG ZT cdti power loss
PostPosted: Sat Apr 04, 2015 8:20 pm 
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I can't see a none return valve causing it may sound stupid but have you done the basics like a new diesel filter ?


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 Post subject: Re: MG ZT cdti power loss
PostPosted: Sat Apr 04, 2015 8:49 pm 
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All the filters are new....no change. :(


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 Post subject: Re: MG ZT cdti power loss
PostPosted: Sat Apr 04, 2015 9:44 pm 
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Havent read you post.
For med/mild power loss or driveabilty issues:
Suspect airflow meter first.
then Lift pumps
then 1 or more injectors
rare to have the inlet, pipework etc clogged from deposits but they do build up over time.


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 Post subject: Re: MG ZT cdti power loss
PostPosted: Mon Apr 06, 2015 7:25 pm 
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mg-richard wrote:
Havent read you post.
For med/mild power loss or driveabilty issues:
Suspect airflow meter first.
then Lift pumps
then 1 or more injectors
rare to have the inlet, pipework etc clogged from deposits but they do build up over time.

:-?


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 Post subject: Re: MG ZT cdti power loss
PostPosted: Mon Apr 06, 2015 8:16 pm 
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simj26 wrote:
mg-richard wrote:
Havent read you post.
For med/mild power loss or driveabilty issues:
Suspect airflow meter first.
then Lift pumps
then 1 or more injectors
rare to have the inlet, pipework etc clogged from deposits but they do build up over time.

:-?


Whats the problem?


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 Post subject: Re: MG ZT cdti power loss
PostPosted: Tue Apr 07, 2015 8:40 pm 
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mg-richard wrote:
simj26 wrote:
mg-richard wrote:
Havent read you post.
For med/mild power loss or driveabilty issues:
Suspect airflow meter first.
then Lift pumps
then 1 or more injectors
rare to have the inlet, pipework etc clogged from deposits but they do build up over time.

:-?


Whats the problem?

Just don't understand why you'd spend time posting without the courtesy of reading my post first?
:?


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 Post subject: Re: MG ZT cdti power loss
PostPosted: Tue Apr 07, 2015 9:28 pm 
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Because in my experience people dont know logger anyway.
So when someone came through the door with a power loss described thats what I would do.
...Plus I found your writing style...annoying....


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 Post subject: Re: MG ZT cdti power loss
PostPosted: Tue Apr 07, 2015 9:34 pm 
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mg-richard wrote:
Because in my experience people dont know logger anyway.
So when someone came through the door with a power loss described thats what I would do.
...Plus I found your writing style...annoying....

You get out of bed the wrong side [emoji38]


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 Post subject: Re: MG ZT cdti power loss
PostPosted: Tue Apr 07, 2015 10:59 pm 
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Marty wrote:
mg-richard wrote:
Because in my experience people dont know logger anyway.
So when someone came through the door with a power loss described thats what I would do.
...Plus I found your writing style...annoying....

You get out of bed the wrong side [emoji38]

Always one on every forum....... :wink:
Thanks anyway.


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 Post subject: Re: MG ZT cdti power loss
PostPosted: Tue Apr 07, 2015 11:08 pm 
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Richard must be having a bad day it's defo out of character I doubt he would of ment to offend in any way.


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 Post subject: Re: MG ZT cdti power loss
PostPosted: Tue Apr 07, 2015 11:18 pm 
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Marty wrote:
Richard must be having a bad day it's defo out of character I doubt he would of ment to offend in any way.


Appreciate your input "Marty". :)
Any more ideas?
Data-logger saying all fuel pressures are fine. There is some discrepancy in the two throttle sensors though? Maybe confusing the ECU as to what fuel is being requested? :?
The problem is, whenever we have the laptop plugged in, the fault doesn't occur.
Every other time, I seem to lose 'boost' at about 2 miles out?
It can't be going in to 'limp' mode, as using the kickdown I can eventually rev it to 4k at which point normal service returns for a few miles?


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 Post subject: Re: MG ZT cdti power loss
PostPosted: Tue Apr 07, 2015 11:41 pm 
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It will be a case of get the laptop hooked up and just keep logging till you get the issue.

If the TPS sensors are out that will not be helping either.


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 Post subject: Re: MG ZT cdti power loss
PostPosted: Tue Apr 07, 2015 11:42 pm 
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Marty wrote:
mg-richard wrote:
Because in my experience people dont know logger anyway.
So when someone came through the door with a power loss described thats what I would do.
...Plus I found your writing style...annoying....

You get out of bed the wrong side [emoji38]


I did, about an hour late as well :lol:


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 Post subject: Re: MG ZT cdti power loss
PostPosted: Wed Apr 08, 2015 12:05 am 
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mg-richard wrote:
Marty wrote:
mg-richard wrote:
Because in my experience people dont know logger anyway.
So when someone came through the door with a power loss described thats what I would do.
...Plus I found your writing style...annoying....

You get out of bed the wrong side [emoji38]


I did, about an hour late as well [emoji38]

[emoji38] was gona say it's defo not like you [emoji38]


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 Post subject: Re: MG ZT cdti power loss
PostPosted: Sat Apr 11, 2015 8:58 pm 
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After having a bit of a think before driving the MG today, I was trying to figure out what was different whenever my mate plugged in the laptop and the fault refused to occur when we went out?
Well,the only thing I could think of was the twisty roads and driving quite briskly with lots of on/off throttle.
So I thought I'd try bit of an experiment, and drove accordingly, not keeping a steady throttle for the whole drive (about a 10 mile loop culminating with the very steep hill on the way home that is usually the biggest problem).
Well, the problem didn't occur once! Flew the whole time with absolutely no loss of power whatsoever.
Now the question is.....Why would the problem only happen on a steady throttle?
Throttle potentiometer?
Low pressure fuel starvation?
Hopefully starting to narrow down the options.


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 Post subject: Re: MG ZT cdti power loss
PostPosted: Sat Apr 11, 2015 10:27 pm 
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Take it back out and log going slow ect will hopefully crop up then :)


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 Post subject: Re: MG ZT cdti power loss
PostPosted: Sat Apr 11, 2015 10:35 pm 
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Yep. Seems worth a try hey! :)


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 Post subject: Re: MG ZT cdti power loss
PostPosted: Tue Apr 14, 2015 1:44 pm 
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I have exactly the same problem. Don't know where to look at.
Rover 75 tourer CDT 2001 (automatic gear).
I didn't do the "steady-trottle-test" yet.
Sometimes the power is back for a few seconds. Very surprising when my car jumps ahead, without changing my right foot!
On the motorway, the gearbox shifts to easy to a lower gear, but the engine can not make high revs. Stay between the lorries...

I was also thinking about the throttle potentiometer.

I am waiting for pscan tool I ordered.
Hope I can find something wrong.

Can someone help me?


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 Post subject: Re: MG ZT cdti power loss
PostPosted: Sun May 31, 2015 9:55 am 
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It was the in tank fuel pump.
The pump sometimes worked and sometimes not.
However, every time I listened, I heard it wordking . After I took the pump out it was dead.
Quite a puzzle to put the tubes and connectors correctly back in the tank.


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