6.5 MPG Disco V8

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compadre

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15
Hello folks, happy new year!
nice forum, first of all, i must apologize for my bad english, i am slovenian and it's hard to me to write and much easyer to read, so i'll try the best i can.
Thanks

So, i got myself a 1996 Disco 3.9 EFI hotwire, auto and LPG. It's a nice Landy and I love it, but..........6.5mpg??
it seems also not all cylinders working sometimes, when cold starts ok, when hot and after a half stopped i have to crank it for 15 seconds to start.
Sometimes i smell petrol but can't locate from where then. The idle is not smooth and the engine will shake/vibrate when stepping the throttle.
The sound isn't also smooth when driving, sounds like an Audi with 5 cylinders and feeling some vibrations from the engine.
Checked the coolant sensor, resistance is falling when warming up, ok, changed MAF, ECU, dizzy cap, rotor arm, cables, ignition module and coil ...all from another, wich was working fine.
Changed the sparkplugs also with new ones (NGK BPR6ES), set ignition on 6° without vacuum hose.....
no vacuum leaks present, stepper works fine (cleaned), TPS setting is ok too....
the behevor on petrol or lpg is the same, no leaks anywhere
cats are removed, lambdas still on, but not checked yet
also i'll try to check all again on the ecu connector, maybe the gremlin is somewhere in the wires

i think the compression is ok, no oil consumtion, no blue smoke, however, the exoust gas smells more like there still cats are present or maybe can smell petrol....or like sweet smell, it's hard to describe
mpg on lpg is very low too

need help, tips, advices, ......please
after lots of googling and using search functions on forums leads me only to confusions, on the other hand, i leraned a lot :)

all best from the sunny side of the alps
 
im no expert on lpg but is it posible your lpg system is feeding gas while on petrol and flooding your engine? just by the smell ?as for poor economy maf sensor is agood start
happy hunting im sure someone in here can give better advice
 
right now i drive only petrol and all the same, the lpg tank is empty now

airflow meter...i read something about cleaning them and adjusting, adjusted it, set it on 1.8V on the first wire from the right on the connector (it was set to 3V and something) while engine was ideling
did i do correct?
 
update;
after i disconected the ecu connector i noticed some bad contacts

discovery-v8-foto_2253270_17419809_18390647.jpg


on the other side, there are two smoked wires (ground)

discovery-v8-foto_2253270_17419809_18390648.jpg


fixed the contacts and measured the wires, it's still ok
checked the signal from coolant temp sensor, ok fuel temp sensor, ok, then we go to lambdas.
Using two multimeters, black cables to ground, red cables to pin 23 and 24.Starting the engine and left bank pending between 0 and 0,85V, rihgt bank between 1,096 and 1,227V....first i think something wrong with the multimeters, so i swiched them and the same come up for the banks....the rihgtone is faulty somehow.
Ok, so what does this mean?
Is it running to rich on the right bank?
Or is this a faulty O2 sensor?
here is a short video i made today, it's shows the behavor of the multimeters during the lambda test:
[nomedia="http://www.youtube.com/watch?v=W7Ocybrs-Nc"]YouTube - testing lambdas (O2) sensors on a V8[/nomedia]

i think, im a little bit closer, but still far from solving my problem
 
If the problem is there on petrol and LPG, that makes me think you have igntion problem.

You say you have set timing to 6 degrees, was this BEFORE TOP DEAD CENTRE ? ie 6 degrees advance...?

Also, once timing light is connected, rev up engine and look at pulley wheel, the timing indicators should move smoothly across the rev range, if the timing appears hesitant/jumpy then you may have distributor timing advance problem.

Also did you set timing with strobe light connected to no 1 cylinder?

Cheers
 
hey
thanks for reply

yes, i set the timing before tdc alt 6°, with vacuum hose disconnected with a strobe light atached to cyl1.
later i chcked also with vacuum accelerating the engine and the timing is going to more advace
however the mark at 6° is bouncing just a little bit (0.5 to 1°) when engine is idle....

today i noticed there is a very little play on the dizzy axle, something about 0.05 to 0.1mm
 
a bit of timing bounce is ok, and a bit of play in the dizzy is ok, just make sure the dizzy still has spring return.

take hold of the rotor arm, it should turn about 10-15 degrees clockwise, and then spring back to normal place. this is the mechanical advance mechanism.
 
thanks for reply
return spring is ok too, it works fine, but tke spark is weak. Is there a kind of extra amplifier for ignition (like years ago for older systems)?
 
yes it will be on the side of the dizzy with two or three wire plug or on later 3.9's on a bracket next to the radiator. its only small
 
i have te one next to the radiator and changrd already, bit the spark is still weak.
Also changed the coil, cap, arm.....
 
Check with your multimeter to see if you have 12v ground from engine (one one - side of battery and other on metal part of engine)
 
all grounds are ok
today i'll change the dizzy, pulled out the oldone already and noticed the timing chain is streched.
made a video with a endoscope: [nomedia="http://www.youtube.com/watch?v=v95mgBa-DgQ"]YouTube - timing chain[/nomedia]

how bad is this?
 
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