Jump to content
The mkiv Supra Owners Club

Black as the ace of spades!!


tbourner

Recommended Posts

So, this could be the reason for my bad idle and occasional backfire that I had on Monday!! :blink:

 

Could this've been caused by the 2 week old petrol (Tesco 99) I had in my car? It was almost empty and started with huge plumes of black smoke and really lumpy; went and got a Jimmy Can of 99 and put it in and it cleared up - not sure if it was a coincidence though (didn't think fuel would go off that badly!).

 

 

 

Question 2: How can I clean it without having any lemon substance in the house (well I've got some fairy liquid!!)? Is it delicate?

o2sensor01.JPG

Link to comment
Share on other sites

Apparently the octane rating reduces though, and with my ECU being used to 99 RON and then getting some dirty low RON stuff shoved through could cause black smoke?

Why else would it be smoking, and then suddenly clear up after a restart?

Then it was fine for a day, then started misfiring!

 

 

Anyway - the O2 sensor looks nasty, how do I clean it? then I'll put it back in and start again (After ECU reset?), see how it goes. The sensor was new less than 10k miles ago so should be fine.

Link to comment
Share on other sites

That wont be caused by the fuel.

 

Not sure I agree, soot like that is a sign of overfueling. The lumpy idle/off boost roughness is another.

 

Thats a really bad state for a sensor to be in. This is what mine looks like

02.jpg

Link to comment
Share on other sites

I meant I dont think its caused by the petrol going off after 2 weeks.

 

Ah, yes. Totally agree with you there, no way will it be caused due to old petrol. Even if it were 'old' all that means is that the octane rating is down, that won't cause the ECU to dump tons of fuel into the engine and cause overfueling.

 

Clean the sensor, check your plugs are not fouled, reset the ECU and see how it is after 20 miles.

Link to comment
Share on other sites

It was Brian in my other thread that suggested a fuel issue, I know it loses octane but I said then I can't believe it'd cause this issue!

 

Eyefi said it could be coolant temp sensor or (very unlikely) air temp sensor, possible?

 

The problem is; something went wrong in the 2 weeks it was sitting on my drive in the cold and rain, so when I started it it sooted up my O2 sensor, and now it overfuels because of it. So what would happen in 2 weeks that would cause massive black plumes of smoke for about 1 minute - then get better?

Link to comment
Share on other sites

So what else would cause mild overfuelling? It could be worse when warmed up but that's based on a single test run!

 

How do you test an O2 sensor? And no the OX1 pin doesn't work because it's overfuelling so the ECU has conpensated for any sensor error!

Link to comment
Share on other sites

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. You might also be interested in our Guidelines, Privacy Policy and Terms of Use.