Now I have seen this on other vehicles but never experienced it myself. I have seen this black tar "stuff" on other cars around the exhaust or on the back if they have rear exhaust. What is this??? I have it on the 4runner now and I really don't know why? I have it on the back of the 4runner, tailgate and window. It is a pain to clean normal car wash will not take it off. Windex will take it off the windows though.

Any Thoughts

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It's carbon buildup. Did it just start showing up randomly?

 

I just got the runner a few months ago and really have not driven it much. Why would there be so much if in fact that's what it is. Why is it really sticky and will not come off when washing?

 

did you recently drive on a fresh paved road?? Is it like road tar?

 

No I know what tar is...it is coming from the exhaust. I have seen this on other cars as well. It's a thin layer of sticky yuck that clings to the back, sometimes side, of vehicles. It covers the tailgate and rear window. It gets there from the air pocket created while driving. I just don't know what causes this.

 

very interesting...ive never seen that

 

Ive seen that happen with brake dust. Truck must be running rich or something...

 

Yeah I used to get that too, but it came off the paint pretty easy at carwashes! I would get mine because I burned a lot of oil, and the truck ran really really rich, it actually smoked more than my grandfathers 12v cummins diesel under full throttle.

On diesels its because they run rich untill the turbo kicks in...so you got a rich condition or you are burning oil!

 

Well I can't smell the fuel but I could be running a bit rich. I'm getting about 10MPG even before I changed to 33's. She is not burning oil at all. I keep checking it and it's fine.

This maybe a dumb question: whats the best way to tell if it's running rich? Smelling the exhaust, checking the plugs??? I'm not sure?

How do I adjust the Mix, do I have to open the AMF and adjust this?

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Well from the outing this past weekend I'm smelling a wee bit of gas. I did dent the tank a bit but I don't think its from that. I'll be looking into it this weekend.

If she is just running too rich should I give the AFM a click or 3? If so which way should I turn it to lean it out some. Or should I look into something else causing this issue? I'm not throwing any codes.

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4Crawlers page has info on the afm clicks..

 

Gee thanks for all your help on this. I know how Google works, I just thought I'd ask for someone's opinion on this. I know a lot of folks have messed with them and some have messed them up. Or could there be another reason for the goo that is forming on the back of the runner. I don't want to adjust the AFMif I don't have to.Sooooo this is why I asked. Your a good helper...

 

Damn.. ZING!

I did some googling for you,( Yes, I know you know how to Google ) but I couldn't come up with anything.. I even went out to my rig and checked for the stuff, but I didn't have any!

Whatever it is, I hope it's nothing serious... fortunately all my problems are pre combustion, post combustion just smells like... well.. exhaust. >.< ( not that I'm prone to sniffing my exhaust pipe or anything )