HELP STRANGE BOOST READINGS

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Craigevo92

Craigevo92

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69
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Widnes
Hi I've got a strange problem on my td5 discovery when I plug nanocom in I get a boost reading of 0.8 bar with the engine not even running removing map sensor from inlet manifold does nothing changed the map sensor that did nothing only way to make it go away is to unplug map sensor then it drops to zero the boost when driving starts and rises from the 0.8 and obviously hits overvoost at very low rev range making the disco drive like **** any idea what else I can try many thanks
 
I might be being a prat, but I think mine used to read the same with the engine not running, I put it down the the sensor reading the air pressure at sea level. Not sure about you overboost thing though . I always used to remove about a bar from whatever figure to get the true pressure.
 
Defender91 said:
I might be being a prat, but I think mine used to read the same with the engine not running, I put it down the the sensor reading the air pressure at sea level. Not sure about you overboost thing though . I always used to remove about a bar from whatever figure to get the true pressure.
Click to expand...
thanks for your reply
Mine stays at 0.79 wether the engine is running or not only time it moves is it rising with boost pressure but it's going from 0.8 to 1.5 bar by 2000 rpm then drops to zero then comes back to life at my wits end with it now
 
Craigevo92 said:
Hi I've got a strange problem on my td5 discovery when I plug nanocom in I get a boost reading of 0.8 bar with the engine not even running removing map sensor from inlet manifold does nothing changed the map sensor that did nothing only way to make it go away is to unplug map sensor then it drops to zero the boost when driving starts and rises from the 0.8 and obviously hits overvoost at very low rev range making the disco drive like **** any idea what else I can try many thanks
Click to expand...
Hi. Read data in the "inputs fuelling" menu not instrument mode, see the manifold absolute pressure and ambient pressure readings and report the results ...it can be the AAP sensor or wiring issue...or in the worst case an ECU misbehaviour
 
sierrafery said:
Hi. Read data in the "inputs fuelling" menu not instrument mode, see the manifold absolute pressure and ambient pressure readings and report the results ...it can be the AAP sensor or wiring issue...or in the worst case an ECU misbehaviour
Click to expand...
Thank you for your reply the readings are
aap around 101
Manifold pressure around 177
Iv tryed wiggling all wires around and there's no change in values regards
 
sierrafery said:
Hi. Read data in the "inputs fuelling" menu not instrument mode, see the manifold absolute pressure and ambient pressure readings and report the results ...it can be the AAP sensor or wiring issue...or in the worst case an ECU misbehaviour
Click to expand...
I'm getting driver demand fault logged and high speed crank on the fault codes aswell
 
Did you check for oil in the ECU red plug?, if it's dry then the ECU is suspect. connect a piece of wire to earth and do somehw to splice into the pink/black wire of the MAP sensor and watch if this affeccts the reading or not also check voltage across the pink/black wire and the white yellow, if it's higher than 5V check across earth and WY
 

sierrafery said:
Did you check for oil in the ECU red plug?, if it's dry then the ECU is suspect. connect a piece of wire to earth and do somehw to splice into the pink/black wire of the MAP sensor and watch if this affeccts the reading or not also check voltage across the pink/black wire and the white yellow, if it's higher than 5V check across earth and WY
Click to expand...
Yes ECU plug is dry I've only just bought the vehicle and to be honest the ECU doesn't look the best it's missing a screw and it says auto remapped on the back when mine is a manual code is nnn500030 I'm going to give all them wires a check and I will update my findings thanks again
 
sierrafery said:
That's a botched up EU3 auto ECU addapted to manual, IMO that's he problem.
Click to expand...
I'm going to try get a demobilized nnn manual ECU tomorrow to try before I go buying one I will let you no how it goes thanks again for your help you have restored some hope in me as I have tryed everything so far with no luck
 
sierrafery said:
Did you check for oil in the ECU red plug?, if it's dry then the ECU is suspect. connect a piece of wire to earth and do somehw to splice into the pink/black wire of the MAP sensor and watch if this affeccts the reading or not also check voltage across the pink/black wire and the white yellow, if it's higher than 5V check across earth and WY
Click to expand...
Update new nnn ECU off a manual and map pressure is spot on can't thank you enough many thanks for your guidance
 
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