White smoke smells like gas

[icebreaker]

Hi All,

I am experiencing a white smoke from the tailpipe and it smells like gas, not all the time , and not when i start the engine, it come and goes randomly, and i feel a bit of hesitation and slight vibration, and the gas mileage is too bad whenever am facing this situation .. the temp is fine and the oil is fine as well, i checked the dipstick many times its normal no milky color or brownish, one more this when the car is cold and i first start it, it vibrates as well .. your help is extremely appreciated ..

Many Thanks

[icebreaker]

its a cherokee xj classic, manual transmission

[4.3LXJ]

How is the coolant level?

[NW99XJ]

The vibrations could be a number of things, but I think the major issue your having is unburnt fuel (obviously.)
This is usually due to something like faulty o2 sensors. These sniff the exhaust, both before the catalytic converter, as well as after, and alter the air/fuel ratio according to what they're reading.
I would suggest replacing the upstream as well as the downstream sensors, and reset the ECU.
The Jeep will run like crap for a little while, until the computer can re-map all of the new data being provided by the new sensors.
As far as the sensors themselves, go with BOSCH, or official Mopar parts only.

[icebreaker]

i really appreciate your help NW99XJ .. coolant level is normal as well.

i just remembered: once (and only once) the temp gauge was on the middle then it dropped down to the low (cool) then back to the middle and so on .. it was like someone was moving it or its haunted or something, but it didnt go further than the middle .. this happened only once.

[NW99XJ]

I do remember hearing once, that the entire soul and well being of the XJ is focused solely around the coolant temperature sending unit. If that were to go faulty, a black hole would open, and tear a rift in the space-time continuum, and life as we know it would cease to exist.
In all seriousness, I would try to find if there is a test to ensure that that particular sensor is working properly. These type of tests usually require a volt meter, and access to the harness/plug of the sensor in question.

[nickyg]

I do remember hearing once, that the entire soul and well being of the XJ is focused solely around the coolant temperature sending unit. If that were to go faulty, a black hole would open, and tear a rift in the space-time continuum, and life as we know it would cease to exist.


Finally!! Someone confirmed what I suspected all along.

[Brasscatz]

Coolant temp sensors are pretty cheap, you could always just replace it. Are you getting any check engine codes?

Sent from my Samsung Galaxy S4 because my microwave couldn't do it

[4.3LXJ]

One more question. Is the smell and steam only right after start up, or when warm?

[icebreaker]

4.3LXJ sometimes on start up and sometimes when warm.

i wanted to ask is there any possibility that it has to do with a bad fuel pump or filter o injections ?

i think i've noticed that this happens when the fuel tank is low, when the fuel tank is above the half or full i dont remember facing the problem i mentioned !

[4.3LXJ]

The reason I asked is that the exhaust hitting cool air will show steam sometimes. It is natural. But it shouldn't happen when warm. I too have a hydrocarbon smell, but I pass CA smog. I understand this is common even in some rigs that pass.

[icebreaker]

Hello Guys, all the symptoms i experienced (white smoke - vibration - oil smells like gas - smoke smells like gas) were bad injectors , i replaced the old set with a new one and all was fine the xj ran back to normal, one more thing the electrical wires for the injectors needs to be checked as well sometimes a bad one or unconnected one might look like you have a bad injector.

[NW99XJ]

Good!, Well I'm glad you got it all cleared up.
Did you upgrade when you replaced?