Disco 2 low power under 2000rpm, can it be MAF?

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Can the MAP sensor be faulty? According to Rave:
If the MAP sensor fails manifold pressure is set to a predetermined default value and the engine performance
will be reduced.
So maybe the turbo does its job, but ECM controls uses preset values and that is why I could never go above 1,2bars?
I will give it a try by MAP disconnected today.
 
some updates..
MAP disconnected, have not felt change in power
exhaust downpipe disconnected but no change on turbo charactheristic. Felt a bit better response, but recorded very similar boost values
Today turbo has removed and checked by specialist. It is like new!
 
Disconnecting the MAP or the AAP is not comparable with disconnecting the MAF cos the default for MAP or AAP unplugged is reduced boost, the vehicle will not run better with these unplugged like it does with the MAF unplugged even if one is fubar.... can't you get hold of a known good AAP sensor and try with that?

So back here then:
berg450 said:
I have just checked. It is with catalyst.
Click to expand...
If the CAT is still there undo the downpipe from the turbo and make a test drive that way(be aware it will be noisy) if it will have power this way the CAT is clogged and that's the root of your problem .... as long as it's no leak and if the turbo was ruled out 100% the only logical deduction for the fact that the boost is not rising enough is that there is a restriction somewhere, are you sure that the intercooler has free flow?
 
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sierrafery said:
Disconnecting the MAP or the AAP is not comparable with disconnecting the MAF cos the default for MAP or AAP unplugged is reduced boost, the vehicle will not run better with these unplugged like it does with the MAF unplugged even if one is fubar.... can't you get hold of a known good AAP sensor and try with that?


So back here then:

If the CAT is still there undo the downpipe from the turbo and make a test drive that way(be aware it will be noisy) if it will have power this way the CAT is clogged and that's the root of your problem .... as long as it's no leak and if the turbo was ruled out 100% the only logical deduction for the fact that the boost is not rising enough is that there is a restriction somewhere, are you sure that the intercooler has free flow?
Click to expand...

This is what I have done. I have disconnected the downpipe and run a few kms like that while the Nanocom was connected. I have felt a bit better throttle response but could not feel improvment under 2000rpm (also the boost values are the same, see attached).

Regarding on AAP: I do not think so...I do not know anyone who could borrow me one.

I have also cleaned the intercooler a few weeks ago. Seemed to be OK. I do not know how I can check if there is a leak (would need to plug both inlet and outlet and somehow put it under pressure...)
 

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You should make somehow to use a boost gauge on that pipe which coes from the intercooler to the wastegate modulator to see if the turbo delivers enough pressure or not...cos if it doesnt and you are sure it's OK it means it's a fuelling issue
 
sierrafery said:
You should make somehow to use a boost gauge on that pipe which coes from the intercooler to the wastegate modulator to see if the turbo delivers enough pressure or not...cos if it doesnt and you are sure it's OK it means it's a fuelling issue
Click to expand...
Done today. Accelerating from 1800rpm in 3rd gear pressure quickly goes up to 1.2-1.4 bars (already around 2500rpm). Around 1.4 bars I have stopped accelerating just for safety. Nanocom also connected and showed these values (attached). Seems that delayed and also lower.
I have also checked the pressure leak of the system from the turbo outlet to the intake inlet. Kept 1bar for an hour. No leak.
 

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sierrafery said:
Those attachments are too small i can't see clear but what's the explanation of this then? https://www.landyzone.co.uk/land-rover/low-power-under-2000rpm-can-it-be-maf.330444/#post-4268768 cos all this discussion was based on the fact that you have not enough boost, which was shown in the first data log too
Click to expand...
You have adviced to attach a boost gage right after the turbo to see the values. This is what I have done. Good values, but still lower at the MAP. In addition to that I had no wastegate during that test which also could influence the values.
It seems my problem is quite complex and as I do not want to waste your time, l propose to finish this thread...I will keep working on it on my way.
 
You are not wasting my time, i'm trying to help you and to understand what's going on but unfortunately i couldnt decript the last two graphs cos they are too small... if you have good boost before the intercooler(at the wastegate pipe) but not enough boost at the MAP and as you'r intercooler is not leaking it might be a restriction in it or the MAP sensor is underreading, do somehow to measure the boost after the intercooler and if you get good boost there replace the MAP sensor
 
It’s not unheard of for the rubber pipes to and from intercooler to delaminate causing restrictions when under pressure
 
The rubber pipes seems to be in good condition (also pressure tight). But just to make sure I will try to measure the boost also after the intercooler. I will try to make a connector to the place of the MAP sensor and connect the pressure gauge there.
Fery, if I remove the MAP, will not the system switch to a mode where it limits the engine performace and also influences the turbo pressure?
 
berg450 said:
Fery, if I remove the MAP, will not the system switch to a mode where it limits the engine performace and also influences the turbo pressure?
Click to expand...
Yes it will, if you remove the MAP is not the best test, better drill into the EGR bypass pipe and cut a thread then you can blank it with a screw after the measurements, at least you'll have a port if you want to fit a boost gauge into the cabin and you can compare the boost with the MAP reading, the internal calculation of the ECU for boost is MAP - AAP so you can see the real boost with a gauge and what the ECU gets... eventually compare the gauge with the boost pressure shown by nanocom on instruments mode and if that is much different and the MAP sensor is good it can be even an ECU missbehaviour so you can rule out many things this way
 
Ok, so the boost measurement has done on the EGR bypass pipe by using professional pressure check device. I have put the gauge next to the Nanocom and registered readings. What I have found is that my MAP a bit "slow" compared to boost gauge. When the boost gauge is already on 1.2 bars it still shows around 0.3 bar and follows the gauge about a second later. The same when the pressure drops back. The gauge is already on 0 and MAP still on 1 bar. But I guess it is normal as the gauge has direct conection and MAP is through the ECU.
Otherwise I have the same values on the gauge and the nanocom (max was around 1.3 bars).
 
Yes.
It was on the MAP but the gauge has never showed more than 1.2 (see attached screenshot).
 

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Then it's not enough boost for some reason especially if it's the same if you clamp the wastegate actuator's boost pipe cos then it should reach overboost limit(1.42) untill max 3000rpm
 
I have made one more measurement at the EGR bypass after disconnecting the pipe from wastegate actuator. The boost has gone up to about 1.6 bar (I have stopped accelerating there) on the gauge while the Nanocom (MAP) showed 100kpa (0bar)!!
When I have accelerated slowly the MAP has followed the gauge but have not showed more than 1.2-1.3 bars. When I have pushed hard (from around 2000rpm to 3000rpm) the gauge has gone up to 1.5 bar quickly while the MAP showed 100kpa!
Can it be remap or my MAP slimply bad?
 
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In this case the MAP sensor is very suspect, you should replace it with a good one before going further.... or the worst scenario is that the ECU has a problem.
 
Tomorrow I will call the guy who has done the remap and ask for some details. Do you think that remap can couse such strange behavior of the MAP?
 
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