bad fuel mileage (Full Version)

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bad fuel mileage

  

verydisco matt -> bad fuel mileage (4/2/2008 4:48:57 PM)

hey to all here, I'm pretty much a total noob with land rovers, bought one on a whim, was hoping for some wisdom...
it's a 95 disco 1 3.9l, got it last week, did all the fluids, plugs, dizzycap and rotor, new vacuum advance module, cleaned ais motor, belt, rear axle seal, etc etc.
I wasn't expecting great mileage, but it's at 9.5mpg, and i don't drive that hard.
the pipe is black as black, and you can smell raw fuel when it's running, it also doesn't idle very smooth, espeically when cold.
I wanted to change the engine coolant tempature sender, but the dealer here will only sell me 5 sensors at a time???!!!
does anyone have a table of resistance for the sensor so I could test it's function?
it has what appears to be two different catilitic convertors on it? mabye one origonal and one aftermarket from the looks of things?one of them rattles internally too.
being that it's running so rich when I got it, I would assume they are probably burned out by now anyway, but could they be a cause of the problem? oh it also has no power at all when floored cold, seems like it's flooding. my thought is to just remove the cats altogether, we have no emmisions testing here, And I don't think it would cause any issues with a engine light or anything....
any other thought on why it might be running so rich?
oh and it has no codes or engine lights on at all.
thanks for taking the time to read this!

  
landrover1502 -> RE: bad fuel mileage (4/2/2008 6:08:51 PM)

hmm air filter? plug wires? fuel filer changed? its obd1 so its gonna take a big problem to turn the engine light on...id start with this

verydisco matt -> RE: bad fuel mileage (4/2/2008 6:58:43 PM)

all new with maybe 300km on them

landrover1502 -> RE: bad fuel mileage (4/2/2008 7:10:28 PM)

ok then it sounds like you need to changed those cats, at least gut them to remove all material inside. 

verydisco matt -> RE: bad fuel mileage (4/2/2008 7:26:23 PM)

is it hard to just gut them? I was thinking of welding in pipe and removing them.

landrover1502 -> RE: bad fuel mileage (4/2/2008 7:31:52 PM)

well you need a torch to cut the side of the cat and peel back the metal, take the stuff out and then weld it back, not a big job for an exhaust shop and hell of a lot cheaper then replacing them.

verydisco matt -> RE: bad fuel mileage (4/5/2008 6:27:16 PM)

well, the origanal cat was totally plugged, and the aftermarket one was ok. we used a 5" grinder with a zip disc and sliced em open, then welded em back together once gutted.
it runs way better now, good power, smooth idle, no more bogging out.
still seems to be running pretty rich from the smell of the exaust.
no one knows the of a aftermarket temp sender?
does this motor have an egr valve? I cant locate one if there is?

Disco Mike -> RE: bad fuel mileage (4/5/2008 6:33:14 PM)

For what it is worth, you can't by pass, gut or remove a cat from a OBD1 system or your ECU will go full rich and you will foul out your engine quickly. You forgot about your 02 sensors.

verydisco matt -> RE: bad fuel mileage (4/5/2008 8:19:46 PM)

the o2 sensors are before the cats, only odb2 would have a o2 after the cat.
no engine light in 150 miles so far.
what about gutting the cats would make it run rich?
with the way it was tottally clogged, the exaust was getting too hot., now it's running nice and open.
I will admit I have little direct knowledge of land rovers, but i am fairly attune to modern engine control systems. I learned lots of stuff playing with k-jet and d-jetronic systems on old mercedes.
I really think it's probably still the coolant sensor, i have seen many go bad and read a improper temp. it doesn't have an egr then does it? and does it just take a signal from the mass air flow sensor, or does it also have a map sensor too?I just set the timing a little more advanced, and this seems to have helped , still maintains proper idle, now running 8 degree's btdc.I would suspect a little advance ok on premuim fuel they probably run it on the conservative side for emmisions purposes.

Disco Mike -> RE: bad fuel mileage (4/6/2008 5:51:24 AM)

Sorry, I was not thinking well when I posted that. If the 02 were behind the cats and you gutted them, the 02's would pick up on it and cause the ECU to go into open loop, hence, full rich.

  

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