1996 Prado 1KZ TE Rough Idle with hunting and insane amounts of black smoke

[jordan_sorabjee]

I had a similar issue. It turned out to be a broken wire to the water temperature sensor. Its the one behind the Injector pump near the firewall, not the water temperature sender at the front. Simple change of the connector and sensor and problem solved for me.

 

[Tractionman]

What's the connection between a broken water temp sensor wire, and the OP's problem of rough idle with hunting and insane amounts of black smoke ?
Just asking, in case I missed something.

 

[Shayne]

There's the trouble with computers in cars you might never know how or why things are connected .

 

[Tractionman]

You're right there with computer systems, but I cant get my head around any relationship with water temp sensor wires, and all the other symptoms with insane amounts of black smoke.
Doesnt compute ! Lol.

 

[Shayne]

Me neither but put the worlds most powerful computer into a barrel and tell it to piss in the corner your going to cause a biblical meltdown

 

[jordan_sorabjee]

So essentially temperature senor assists the ECU to decide how much or little fuel to inject. When it can't do this the idle can be rough or it will hunt. Also, it may cause it to over fuel hence the black smoke.It may do this without throwing an error code. Mine didn't. To be fair, mine was smoking bad, but nothing like what is being described by the OP.

One other thing worth checking. On the side of the injector are two resistors, one for fuel the other for timing (I think the grey is timing, beige is fuel). Check the connections are ok and also that they are in spec. Would have thought this would throw an error code though.

 

[Tractionman]

Good answer.