VX using leaded fuel

[ahmedomnnea]

Hi,

I have a 2002 VX with 3.8L V6 engine, Auto trans, All stock (no mods at all).
the only fuel we have in iraq is leaded fuel, my qustion is:
what parts in my car that using leaded fuel can hurt?
I already have a low gas mileage problem, the best I can get is 20L/100Kms.
the car seems to Idle rough and probabily because the fuel isn't good it has advanced timing and lots of engine knocking especially when the A/C is on.
checked the O2 sensors and their readings seems right (arround 600 mv), new fuel pump/filter, new air/oil filter, new spark plugs, cleaned MAF and IAC and throttle body, checked the coil packs and seems working fine (spark moves from one to the other),checked for vacume leaks and everything looks fine.

is using leaded fuel can cause all these problems?
and one last Q:
could a cloged cat converter cause rough idle and poor fuel economy?
any help will be realy appreciated.

[VK SL 3800]

Leaded fuel is bad for an unleaded car, it will normally destroy the cat-converter, and cause it to clog. As for engine knocking it is probably because the fuel is too lower octane and the engine is not designed to run on it, but engine knock should be eliminated if the knock sensor is working as it retards the timing when it detects a knock. I'm not sure what exactly the lead in the petrol will do to other parts of the engine and fuel system but i would imagine it cant be good for pumps, seals ect. But i highly doubt it would effect major components like the pistons valves & seats as it was originally in the fuel to lubricate the valve seats anyways.

[RiCeY]

Leaded fuel will kill the catalytic converter and that in turn will cause rough idle and misfiring as well as poor fuel economy.

[delcowizzid]

o2 sensor and cat is all it will damage.normally the overseas leaded cars dont have cat and o2 sensors

[ahmedomnnea]

thanks guys for the quick replys,
overseas cars do have O2 sensors and cat.
I will take it tomorrow to a mechanic to check the cat converter, if cloged I will remove it alltogether and replace it with a pipe !!!!, we don't have environment and polution regulations in Iraq.

[REDNUT 80]

all the lead does in fuel is lubricates the valve seats, this is why to change a leaded motor to unleaded you need hardened valves, also the leaded fuel was acuatly higher octain then the regular fuel we get in Australia, so chuck out the cat and it should be a little better

[vr1uz-fe]

yes leaded dose have a higher octane and is better for the engine in fact if i could i would run leadded in my car but we do have those enviromental laws here so we have to run cats

but a mate is part of a new hydorgen tec for older cars and sells the kits for 3500 so im gona rangle one of those for my beast

[ausrs]

o2 sensor and cat is all it will damage.normally the overseas leaded cars dont have cat and o2 sensors

i have seen some of the saudi cars (in fact i drove one in sydney ...........no cats on the ones we looked at either

[delcowizzid]

ive been trying to get a copy of the saudi tune for ages and ages

[ahmedomnnea]

ive been trying to get a copy of the saudi tune for ages and ages

whats so special about saudi tune?

[ahmedomnnea]

i have seen some of the saudi cars (in fact i drove one in sydney ...........no cats on the ones we looked at either

well mine has a cat.

[delcowizzid]

the saudi cars have no cat no o2 sensor and are setup with open loop fueling im interested in checking it out is all.if you are running leaded fuel you want that tune no cat and no o2 sensor lead kills o2 sensors and cats pretty quickly.

[ahmedomnnea]

the saudi cars have no cat no o2 sensor and are setup with open loop fueling im interested in checking it out is all.if you are running leaded fuel you want that tune no cat and no o2 sensor lead kills o2 sensors and cats pretty quickly.

thanks for the quick reply,

but my VX has a cat and O2 sensors, and it has very crappy fuel economy (25L/100Km), do you recomond that I remove the cat and O2 sensors for better fuel economy?

[delcowizzid]

your cat is probably meted or contaminated badly and the o2 sensor is probably reading real slow and/or wrong voltages which will suck gas .you cant run without the o2 sensor on and o2 sensor tune so you will have to fit a new one and just fit them more regularily than normal

[VK SL 3800]

You cant exactly remove the 02 sensors, if its got them then its tuned to run with them so removal will just put the check engine light on and cause it to run rough and probably go into limp home mode.

[ahmedomnnea]

You cant exactly remove the 02 sensors, if its got them then its tuned to run with them so removal will just put the check engine light on and cause it to run rough and probably go into limp home mode.

thats the thing,
when I disconnect the O2 sensors it doesn't come up with the check engine light !!!, but it comes up when disconnecting the MAF or MAP or TPS.

[delcowizzid]

did you drive it with it dissconnected

[ahmedomnnea]

yes, no difference !!!

[delcowizzid]

sure it was the o2 sensor you unplugged LOL there is 2 one on each side exhaust manifold

[ahmedomnnea]

I know there is two of them, and I unplugged both of them with no difference in power, fuel economy and feel, its the same and with no check engine light !!!
then I've cleaned them and plugged them back again but still the same.

[delcowizzid]

strange maybe it has the leaded tune but has o2 sensors in it for some silly reason does it only have 2 sensors or 4 some of the vx had before and after cat sensors.ide loose the cat for a start

[ahmedomnnea]

it has only 2 O2 sensors, 2 wires on each one.

[Tree cutter]

We have four wires on our o2 sensors. The extra wires are for the heater circuit in the sensor so it works quicker. I would take the cat off or smash the guts out of it to stop the rough running and pinging. I dont think you can clean the lead off your o2 sensors, they are normally a throw away item and will make your car drink fuel when they are faulty. A dirty fuel filter will also give you bad fuel economy.

[ahmedomnnea]

but why no check engine light when I disconnect the O2 sensors? if they are the key to optimum fuel consumption, should I be getting a check engine light on when they are disconnected?
I chande fuel/oil filters regularily, new fuel pump, so I guess I have no problem there.

[gazza.G.B]

Did a fuel run on E10,91 95.city run E10 -13.5 l/100k
91 - 11.5
95 - 11.5
and h/way 91- 8.9l/100k..price of fuel E10 $1.14 L
91 $1.18 L
95 $1.26 L
so value for money is 91 unleaded.