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 HOWTO: Diagnose Rover Diesel - Sluggish & Limited to 4000rpm 
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 Post subject: HOWTO: Diagnose Rover Diesel - Sluggish & Limited to 4000rpm
PostPosted: Tue Jan 05, 2010 2:32 pm 
RT GOD

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Right ive had so much of a bugger on with this over the last week, ive done everything and fixed the problem today. If there was a guide on here or somewhere my life would have been so much easier.

THE CAR

Rover 45 Diesel with L Series 2.0 w/Electronic Diesel Pump
Should cover all L series Diesels.
Problem will probabaly not be MAF related on non-intercooled versions.

THE PROBLEM

Car will not rev past 4000rpm
Sometimes coupled with sluggish revving up to 2000rpm (takes around 6 seconds, then when on boost pulls fine)
Poor MPG
Engine sounds like a tractor.
No Engine Management Lights on.

THE CULPRITS

1. MAF Sensor.

This is more important on the L Series Intercooled as on the non-intercooled the ECU doesnt reply so heavily on its reports to make the engine run correctly. It is held in with two Torx Security bolts. If you dont have a Torx driver, simply use a hacksaw to cut a groove in the top and use a flathead screwdriver.

This is located here:

Image

If you have poor performance below 2000rpm, coupled with the 4000rpm wall, your MAF is faulty. If you have the 4000rpm wall, but NO LOSS in performance up to 2000rpm, move to STEP 2

The price of a new MAF sensor is an unbelieveable £138 for a genuine Bosch one. Cheap copies do not have Bosch marked on the side and are usually shipped as just the sensor - whereas the bosch one comes with the pipe that fits between your inlet and airbox. I simply bought one off an 04 Express which was being broken for £20 delivered.

If you suspect your MAF is faulty, you can check the voltages on the plug at idle. The pin out is:

Pin1 - Variable (air temp sensor)
Pin2 - 12v (or what your battery voltage is)
Pin3 - 0v
pin4 - 5v
Pin5 - 1v with engine off, 1.6v at idle, 3v when revved.

Check all these Voltages and all associated wiring. You can also check all the way from the MAF plug to the ECU. The white wire from the MAF goes to pin 88 on the ECU. This information can be used to check continuity and that there are no breaks in the wiring causing problems.


2. The Needle Lift Sensor

Your Rovers ECU uses a piezoelectric transducer to detect detonation by sampling the vibrations of the engine block and also to detect the precise moment of fuel injection. This is more commonly known as the Needle Lift Sensor.

The Needle Lift Sensor is built into Injector Number 1 and access is superb by Rover standards. You will have to remove the engine noise cover where fitted. Look behind no1 Injector and you will see a 4mm thick wire coming from it towards the front of the car and connecting to the main engine loom under the front top boost hose.

Located here:

Image

Check it is connected, check all the wires going into the shielded loom. Mine was snapped here and disconnected. After some soldering it all went smoothly from thereon in.

It was allegedly common knowledge that the Needle Lift Sensor will activate the engine management light upon it being disconnected or broken. This is incorrect, at least on my engine.



Significantly more information can be found on the L Series engine here:

http://tuning-diesels.com/Edc15m/edc15m.htm

HTH
Paul.

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 Post subject: Re: HOWTO: Diagnose Rover Diesel - Sluggish & Limited to 4000rpm
PostPosted: Tue Jan 05, 2010 9:59 pm 
RT GOD


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It is a VERY common problem on 25/45/zr/zs models. The MAF sensor only controls the EGR on the 200/400/600 models so it is not applicable for these.

more info on my website I think.

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 Post subject: Re: HOWTO: Diagnose Rover Diesel - Sluggish & Limited to 4000rpm
PostPosted: Tue Jan 05, 2010 10:04 pm 
RT GOD


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I can't see how the needle lift sensor can detect detonation - it's wrapped around the injector and merely detects movement of the pintle, to feed back 'start of injection' information to the ECU - it uses this in a feedback loop with the timing adjuster in the injector pump.

All of the documents I've read have alluded to this; a diesel is operating in permanent 'detonation mode' anyway - that's how it ignites the fuel.


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 Post subject: Re: HOWTO: Diagnose Rover Diesel - Sluggish & Limited to 4000rpm
PostPosted: Tue Jan 05, 2010 10:12 pm 
RT GOD

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I hadnt seen your site until tonight, just had a good look - very, very informative.

The above annoyed me so much as I was concentrating my efforts around the MAF as just about all information on the net about the early limit points straight to it. It was really a chance comment that pointed me towards the sensor on no1 injector.

When i got the car the MAF was disconnected leading me to believe the previous owner got nowhere with it either.

@bgunn, I had to have a damn good read up on it myself but:

Image

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 Post subject: Re: HOWTO: Diagnose Rover Diesel - Sluggish & Limited to 4000rpm
PostPosted: Tue Jan 05, 2010 11:05 pm 
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Very nice write up, sticky material. :)

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 Post subject: Re: HOWTO: Diagnose Rover Diesel - Sluggish & Limited to 4000rpm
PostPosted: Tue Jan 05, 2010 11:29 pm 
RT GOD


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The last paragraph of that says exactly what I was saying ;)


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 Post subject: Re: HOWTO: Diagnose Rover Diesel - Sluggish & Limited to 400
PostPosted: Sun Feb 02, 2014 5:48 pm 
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Sorry if this is the wrong place to post a question but im new to this forum and couldnt see where to ask a question. This topic sort of relates to the problems im having. I have a 2.0td mg zr, The car is limiting at 4000 revs, theres definitely boost there but doesnt seem as much as it should be... Its only hitting 35mph in 2nd gear! Should be alot quicker, Ive unplugged the maf sensor from the air pipe and took it for a drive to see if it made a difference in case the maf was faulty but it didnt make any difference at all. Please try and lead me in the right direction of what it could be cause its so annoying knowing that the power is there but you cant use it! Thanks


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 Post subject: Re: HOWTO: Diagnose Rover Diesel - Sluggish & Limited to 400
PostPosted: Sun Feb 02, 2014 5:55 pm 
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dan_knoo wrote:
Sorry if this is the wrong place to post a question but im new to this forum and couldnt see where to ask a question. This topic sort of relates to the problems im having. I have a 2.0td mg zr, The car is limiting at 4000 revs, theres definitely boost there but doesnt seem as much as it should be... Its only hitting 35mph in 2nd gear! Should be alot quicker, Ive unplugged the maf sensor from the air pipe and took it for a drive to see if it made a difference in case the maf was faulty but it didnt make any difference at all. Please try and lead me in the right direction of what it could be cause its so annoying knowing that the power is there but you cant use it! Thanks




Go here

viewforum.php?f=59

And click New Topic mate

You are more likely to get a better response


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 Post subject: Re: HOWTO: Diagnose Rover Diesel - Sluggish & Limited to 400
PostPosted: Sun Feb 02, 2014 9:09 pm 
RT GOD

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Holy thread revival! Id say its the wiring from no1 injector coupled with a dodgy MAF.

The 4krpm limit is the indication of the first. Any engine light? Does the turbo come in when driving?

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 Post subject: Re: HOWTO: Diagnose Rover Diesel - Sluggish & Limited to 400
PostPosted: Wed Jun 24, 2015 5:13 pm 
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Is pin 88 easily identified?


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 Post subject: Re: HOWTO: Diagnose Rover Diesel - Sluggish & Limited to 400
PostPosted: Wed Jun 24, 2015 5:15 pm 
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As just tested the colts on pins going to maf and not even getting a volt. On white wire.


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