nicolafabbri

New Member
I had a problem with my Discovery 4 SE, 2013 3.0L, I'm pretty sure that this happen after replacing the gearshift oil and differential box oil, but not 100% sure.
In any case, now engine accelerate very slowly from minimum up to 2000 RPM circa, so starting the car is a nightmare! This always happen, and problem is present even in neutral gear! So it's not a problem of Normal, Reverse or Sport mode, even in neutral mode, if I press the throttle, engine raise up very slowly up to 2000 then suddenly start.
This is the same behavior that I have in drive, or in sport mode, but clearly when I quickly push the throttle for accelerating and engine is under 1800 RPM or circa, gearbox change and with a lower gear the performance return as normal.
No problem of power at high RPM.
No problem of smoke.
No error in ECU.
Car has 150.000 km.

Any suggestion?
 
Any warning lights on the dash?
No, no light. Only some time in the past, appears an error with "restricted performance", but after a power off and restarting this disappear. But only one time, I had a yellow light on, and in this case error was this:
1748986723240.png


But without any intervention after some km of driving then light switch off. I have not checked now if error still or not.
 
I've a client with a D4, it spends a lot of its time doing short journeys, after a run to England and when coming off the motorway it wenr into limp /restricted performance. Due to sooty or unexercised components.
I put it on the diagnostic tool and recalibrated the turbos, egrs and associated valves and told him to drive it with more spirited behavior.
This was last year and so far. .
It was the least invasive approach 🤔
 
I've a client with a D4, it spends a lot of its time doing short journeys, after a run to England and when coming off the motorway it wenr into limp /restricted performance. Due to sooty or unexercised components.
I put it on the diagnostic tool and recalibrated the turbos, egrs and associated valves and told him to drive it with more spirited behavior.
This was last year and so far. .
It was the least invasive approach 🤔
Next week I can try.
 
Another point, my cheap EOBD tool (Mucar V06) allow to see and graph some data, what i found is that there is 2 mass flow, one seem showing a flow, while the second one still to 0, I have not checked if situation change while driving but in Neutral seem that only one read flow. It's normal?

What is the parameter that I can monitor to see if there is some fault o error on signal? I can try to acquire and map to share.
 
@Mark Piercy or @gstuart will know I expect. but to me it doesn't sound normal at all, unless it is to do with twin turbos or something?
You can tell I don't have a D4!

But on a D2 TD5 this is typical of a misbehaving MAP/Iat sensor.
On THIS engine you can disconnect the MAF and it puts the ECU onto a basic map which you can drive with, but I don't know if you can do that with yours.

I'd go for a drive and get someone to wathc the data. I take it you did rev the engine up, not just leave it on tickover?
 
Another point, my cheap EOBD tool (Mucar V06) allow to see and graph some data, what i found is that there is 2 mass flow, one seem showing a flow, while the second one still to 0, I have not checked if situation change while driving but in Neutral seem that only one read flow. It's normal?

What is the parameter that I can monitor to see if there is some fault o error on signal? I can try to acquire and map to share.

I dont know the car, but often have a noisey of freds to learn mayb?

So I did a little search and came across this on another forum about MAF sensors. true or not I dont know and they didnt mention a fix as the OP was only talking about "were his readings right or wrong"

"I'm sure you've got this sorted now - however if you haven't - for info. The TDv6 3.0 engine has a twin turbo system. One is the cruising turbo (right hand side of the engine if your standing in front of the car) which is fed air from the bank closest to the front of the car. At ~2800rpm the secondary turbo (located on the left hand side of the engine) kicks in and pulls air in through the secondary air supply (the second rear maf sensor) the two turbo outlets are then mixed together in an intelligent way before going through the intercooler and into the inlet manifolds.

You cannot really diagnose the issue with just reading the MAF sensors output."


So it would be difficult to get a reading on the drive, and would best be driven and monitored by the sounds of it.


I will now continue to watch :).

J
 
I dont know the car, but often have a noisey of freds to learn mayb?

So I did a little search and came across this on another forum about MAF sensors. true or not I dont know and they didnt mention a fix as the OP was only talking about "were his readings right or wrong"

"I'm sure you've got this sorted now - however if you haven't - for info. The TDv6 3.0 engine has a twin turbo system. One is the cruising turbo (right hand side of the engine if your standing in front of the car) which is fed air from the bank closest to the front of the car. At ~2800rpm the secondary turbo (located on the left hand side of the engine) kicks in and pulls air in through the secondary air supply (the second rear maf sensor) the two turbo outlets are then mixed together in an intelligent way before going through the intercooler and into the inlet manifolds.

You cannot really diagnose the issue with just reading the MAF sensors output."


So it would be difficult to get a reading on the drive, and would best be driven and monitored by the sounds of it.


I will now continue to watch :).

J
Aha!
but to me it doesn't sound normal at all, unless it is to do with twin turbos or something?
So I was at least half right then.
I'd be very tempted to try and drive it with the faulty MAF disconnected to see it they have a "get you home" map.
 
So I was at least half right then.
I'd be very tempted to try and drive it with the faulty MAF disconnected to see it they have a "get you home" map.

I dont know if the MAF is faulty as he cant get readings the way it was done (by the sounds of it).
It does have a "get you home" its called "limp mode" I.E restricted performance.

I dont know if the MAFs are the same, if they were I would say swap and see if it follows the MAF in the same test.

J
 
I dont know if the MAF is faulty as he cant get readings the way it was done (by the sounds of it).
It does have a "get you home" its called "limp mode" I.E restricted performance.

I dont know if the MAFs are the same, if they were I would say swap and see if it follows the MAF in the same test.

J
Good idea, if there is no other suggestion I can swap, they are absolutely identical.
But I expect that in this case ECU should have an internal error! Or not?
 
Good idea, if there is no other suggestion I can swap, they are absolutely identical.
But I expect that in this case ECU should have an internal error! Or not?

As far as I would say the ECU sees it as just "a sensor" only. so as such it should be recognised without any issues.

Do remember I dont know the D4 or the engine well.

as well as who has already been tagged I would add @tyregeezer for any insights/suggestions

Also remember your cheap OBD reader may be very limited in telling you things.

J
 
Remember the airflow meter code you had put up was a historic one not a current issue. I've seen this before on a disco 4.
Unless its a current or permant fault don't worry about it.
Airflow meter, high air flow is usually an egr valve not opening.
The computer expects to see the airflow drop when the egr valve draws in exhaust gasses👍
 
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Yes as above, historic code, seems you are getting intermittent faults, egr will cause these issues as said, could check induction pipe work for leaks, also vacuum system has a connection or knock on to everything on your list of faults
You can switch maf sensors fault will follow, the one I bought would only run with mafs unplugged
Would do a good visual check on everything mentioned in your fault code, wiring, vacuum and induction as first step, working on a D4 at the moment many issues with vac lines amongst others all the best
 

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