Found clean intake channel... what can cause that?

[Kliv]

Hey guys!

I took my intake tank off today and found that 6th cylinder channel is clean when others have soot as expected (see the pic). That is not a light from the lamp on photo makes it shine - it is really clean!

What do you think? What can cause that?
I think that it might be an issue with ignition coil and spark on 6th simply does not work. So, I run 5 cylinders only

Any ideas are welcome!

Btw, there are no Check Engine lights, issues with Idle or something.

 

[me_rikey]

i would doubt you're running on 5 cylinders, i would think you would most definitely know if you were; however, this is certainly interesting. i wonder if #6 could be running too hot/ cold? interesting indeed.. sorry i can't be much help.

 

[Casper421]

Kliv, is your 4runner an 04 by chance?

 

[Kliv]

Kliv, is your 4runner an 04 by chance?

Whoops... 2003... Fixed my signature
Is there any difference re intake?

 

[BlackWorksInc]

There a number of possible causes as to why the intake is nice and clean, anything from its not getting any fuel or air at all, to fuel is washing out the intake passage and thus it doesn't soot up.

Do you have any performance issues with the vehicle? Or is it running fine with just this oddity?

 

[jdkilroy]

I have to admit some ignorance here but why is there soot in any of the intakes... ? This is pre-combustion right ?

 

[goohead]

Vacuum between the throttle body and the cylinder is used to re-circulate fumes and vapors that builds up in the crankcase.
You are fine, unless you are getting misfire codes

Prob just a baffle on the intake manifold

 

[Kliv]

Well, I had no issues with the truck until I found it. Runs well, no issues with acceleration, no error codes. Got bigger fuel consumption (12-13 MPG) comparing with the rate I had at very beginning (16-17), but I installed 33", lifted it up, added armour... So, increase was expected.

Now I have misunderstanding issue at least

Guys on local forum assume that it might be an issue with the head gasket. So, I got coolant in 6th cylinder which washes my intake.
If anybody who had the gasket broken and replaced would comment on the topic - have you seen the same clean intake on your trucks?

I doubt that fuel itself can clean the cam so nice. It must be something else added to it.

 

[PWGUNNY]

a leaky head gasket has a very distinct odor, you would notice it. I live by the motto,"If it's not broke, don't fix it". Unless your truck is having performance issues, I would leave it.

 

[Kliv]

Valid point. Such motto makes perfect sense, but I have a lot of parts disassembled already. My timing chain cover leaks and I am heading to fix that.
That is 80% of all what should be done to replace head gasket.
Keeping in mind that most of 4R owners have issues with that around 150-250 k miles and my just went though 150... don't really want to do all this disassembling once again next year.

I think I will go forward with it. Will keep you posted.

 

[Kliv]

So, head gaskets are fine. Looks like we will not find the cause for the anomaly...
In any case, I cannot say that all the work was done for nothing. I found soot in cylinders - level is acceptable, but will see how it will run without it.
Here they are:

 

[riceandpho]

Whens the last tune up done? Looks like u can clean it good and have it shiny again.

 

[Kliv]

Whens the last tune up done? Looks like u can clean it good and have it shiny again.

I've never got inside this engine before. Will definitely clean cylinders, heads, valves, set clearance etc.. Will see how it runs.

 

[450exc115]

Could just be as simple as the crank case gases don't make it to that runner. Is the soot progressive less as as you get away from the crank case vent?

 

[krupnation]

Just so I'm clear here, you have time to take apart your engine when there ISN'T a problem? Wow, I need your life!

 

[Kliv]

Could just be as simple as the crank case gases don't make it to that runner. Is the soot progressive less as as you get away from the crank case vent?

That would be too simple if it was so. But that is not the case. 5 of them got same level of soot, but 6th is completely clean. I think that throttle cleaner can be the cause... I can remember that I used it - as per manual you spray it into the throttle while engine is running. I think that it may get into 6th hole only due to intake shape.

Just so I'm clear here, you have time to take apart your engine when there ISN'T a problem? Wow, I need your life!

:lol: I got second car - that makes things different