D 2 with some problems

i cleaned it but didnt change it . i could try and swap it for another and see

just to update ive got my Hawkeye and the ABS was a repeat fault of rear left wheel sensor low or broken wire so i changed the sensor and cable from the wheel to the multiplug at the front by the expansion tank . it works good now i havent got the amigos since . the kickdown problem seems to be a bad MAF i swapped it for another (not sure if was a good one) but it still says air flow low .

Check your live MAF readings with HawkEye:

Discovery 2 --> EMS --> Td5 --> Live Data --> Air Flow

Should be between 55-65 Kg/hr at idle and 550-620 Kg/hr at full boost
A partially busted MAF will read 30-40 Kg/hr at idle and max out half way through when at full boost.
A totally busted MAF will read 4.4 Kg/hr all the time (same as having engine off)

If MAF is busted might just disconnect it and will likely get better engine performance (ECU picks up 'default' MAF curve).

its not reading anything its 0.00 all the time . is there a test to see the maf is getting power( how much voltage at the plug) and a resistance value of the maf itself ? i would like to test it but im unsure what values are good or bad because i doubt both mafs are bad but i could be wrong.

oh i did run it with the maf disconnected but it made no diffrence in performance

The MAF sensor gets battery voltage from the main relay in the engine compartment fusebox. This 12 volt supply is provided via fuse 2 and received at pin 3 of the sensor connector. Signal output to the ECU is a variable voltage proportional to the air drawn into the engine, measured at pin 11 of the ECU connector C0158 ("the red plug"). The earth path is via pin 20 of the same connector.

With the above, plus the schematics here below and a multimeter, you should be able to determine whether the faut lies in the fuse, the loom, or the MAF itself. Pouring rain today, will check mine as soon it clears out.

Resistivity values from a known good MAF sensor:

Pins 1-2 = 16.8 kohm
Pins 1-3 = ~34 Mohm
Pins 2-3 = ~34 Mohm

thank you sir i will check as soon as i get a chance and report back

well ive checked it and it seems the MAF itself is bad and so was the one i swaped .the original one reads
Pins 1-2 = 16.8 kohm
Pins 1-3 = 12.28 Mohm
Pins 2-3 = 12.33 Mohm
the second one that i tried reads
Pins 1-2 = 16.8 kohm
Pins 1-3 = 19.38 Mohm
Pins 2-3 = 19.34 Mohm
so i will need a new one the power supply and ground wires are all good and arent broken or cut so thats good .

For the sake of curiosity I checked a bad MAF (a real bad one):

Pins 1-2 = 16.8 kohm
Pins 1-3 = 6.23 Mohm
Pins 2-3 = 6.25 Mohm

So then all MAFs, either good or bad, have the same conductivity between pins 1-2, and conductivity between pins 1-3 and 2-3 appears to decrease as the MAF deteriorates.

i thought the same thing when i checked them:scratching_chin:


oh thank you again for the info on the MAF it was very helpful

defcrazy said:

ive noticed when the mode button is pressed it goes to "S" sport but when pressed again it goes back to normal and not to 'M" manual mode so i suspect the trans ECU is the problem

Click to expand...

This us what it's supposed to do. M mode is only when in low ratio.

ben.suffolk said:

This us what it's supposed to do. M mode is only when in low ratio.

Click to expand...

yes i was mistaken that is how it works :doh:

well i think ive also found the "kickdown " problem i was checking the strainer in the fuel pressure regulator and when i refitted it the disco wouldnt start so i opend the fuel filter (it looked good ) but i still couldnt get it to stars after many attempts of bleeding so i changed the fuel pump with a good used one ( the last owner fitted a new one ) and it started first time, so that was fine i got it to start but when i took it for a drive i found loads more power and the kickdown was normal .

so it turns out the engine was suffering for fuel on higher revs causing the kickdown to feel like it was . oh yea i still havent changed the MAF .