SLOW V8 Disco 2

[mrapocalypse]

I am currently kicking the pants out of my V8 Disco 2 becuase it is low on power. It hates going up slight hills in top gear and will just slowly die in the power stakes.

Put a new (Non Genuine) MAF in and noticed a very slight improvement in overall performance but main problem remains. Transmission is nice and loose and kicks up and down well and I have done the famous Control Alt Delete to reset OBC!

What sensor shoul I replace next????? O2, Throttle position sensor. It's fun abusing it but the party can't go on forever!

Ian.

[mike 90 RR]

I am currently kicking the pants out of my V8 Disco 2 becuase it is low on power. It hates going up slight hills in top gear and will just slowly die in the power stakes.

Put a new (Non Genuine) MAF in and noticed a very slight improvement in overall performance but main problem remains. Transmission is nice and loose and kicks up and down well and I have done the famous Control Alt Delete to reset OBC!

What sensor shoul I replace next????? O2, Throttle position sensor. It's fun abusing it but the party can't go on forever!

Ian.

Going out on a limb here .... Does it have a distributor with a "vacuum advance" on the side of it???

[njz]

D2 V8s run coil packs.

[mrapocalypse]

It also has a whole new set of Leads..... It does it on LPG and petrol too!

[Romulus]

hi,

since your problem is on both LPG and petrol and you've done most of the ignition side of things, have you checked compression on all 8 pots, also, might pay you to check each coil pack for output voltage as well, cheers.

[mike 90 RR]

D2 V8s run coil packs.

Thought so ;)


It also has a whole new set of Leads..... It does it on LPG and petrol too!

Your not complaining about it missing?? .... just lack of power

I was going up the "timing is retarded" track .... as in the spark is not advancing and is stuck on TDC



IF you are going to change sensors .... Wouldn't pluging the ECU into a "reader" bring this fault code up ... Gotta be cheaper than replacing at random

Mike

:)


Note for the car makers ...... Bring back the Distributor & KISS

[mrapocalypse]

I actually think it's the NON Genuine MAF! I have since read on here after a search that some from the UK Don't actually work so well in Aussie V8s. Might look at sourcing a Genuine LR one for an Ausssie Spec engine and wee where that gets me. I would stick it on a computer but it has recently been through all that and nothing came up.

I am not too worried about buying extra sensors because they are a worthwhile additon to the spares kit if things don't wok out!

[PhilipA]

AFAIK the discussion about air flow meters refers to the old flappers.
I do not THINK there is a difference in the Bosch MAF used in Discos,BMWs etc etc except for size of tube and connector.
Look I believe your first step is to go to a specialist and put the car on an analyser.
If you find something out of spec then replace it.
Seeing the Bosch Motronic used in the D2 is very powerful and if no error codes are there its unlikely something electronic is wrong.( although I must concede that MAF errors do not always show up on BMWs with Motronic. BUT they can show up as o2 sensor errors) . Maybe swap a known good MAF in.

Third step is to put it on a dyno to see what sort of power is there . It may be normal.
if you are still unhappy the problem may be mechanical. Look at the compressions, and visually inspect the camshaft.
A worn cam can show as gradually reducing power but no misses etc.
if its not the MAF then all that should cost you less than a MAF.
Regards Philip A

[mumbo]

i just replaced my O2 sensors. They are easily tested using garage equipment but you can also get a kit for $15 from jaycar. it means soldering it up but its not that hard.
it has removed the problem of bad running. Admittedly my gas was working OK and the problem was only on Petrol.

[tempestv8]

I've never been impressed with the 4.0 V8. But I do agree that MAF sensor and O2 sensors are key to it's performance. As well as at least 95 octane petrol, otherwise the computer will simply retard the ignition advance to the point where it's running poorly.