dtc code p0306

[grabber07]

I tried searching out answer before I posted.
-I know its a misfire on # 6 cylinder
-I switched plugs first (brand new hto's gapped at.030)misfire stayed on #6
-I switched cops misfire stayed on #6
-I switched injectors misfire stayed on #6
-wiring appears to be ok from what I can see
-seems to throw code at lower rpm
I just installed built shortblock,have a turbonetics turbo kit on it stock top end.Sometimes after I clear it and restart after letting it sit car it runs fine then will throw code and run rough .Any help is appreciated.

Thank You
Steve

 

[lito]

Do you have aftermarket cams by chance?

Is this the only code?

 

[grabber07]

No cams,yes the only code.

Steve

 

[lito]

Any access to someone with dealer tools that could do a cop test with a VCM&VMM?

Any access to someone with an oscilloscope that could trace signalling on #6 and compare with other cylinder to determine if it is ok in the coil and injector side.

I really dislike to assume a PCM is at fault because I haven't seen a single one going (by themselves, seen a couple burnt by stupidity) but maybe that cylinder inj or coil driver is giving trouble (specially if it works cold and then stops working).

Crazy test idea: could be talking to your tuner to build you a temporary tune with a different firing order and where he would switch nearby cylinders and do the same physically so it will still work but see if the problem switches to the other cylinder you would be sure it is a PCM driver problem (that could be fixed, done here with edge and fusion PCMs)

 

[grabber07]

I don't have access to any of what you mentioned.I do have a question about compression.I read that low compression can also throw a code.If a tune was started off a base turbonetics file,isn't that tune designed for the stock block compression?Now with mine being lower compression 8.5-1 would this be a possible or would it throw multiple codes.

Steve

 

[lito]

I don't have access to any of what you mentioned.I do have a question about compression.I read that low compression can also throw a code.If a tune was started off a base turbonetics file,isn't that tune designed for the stock block compression?Now with mine being lower compression 8.5-1 would this be a possible or would it throw multiple codes.

Steve

Well, that would happen only if compression is so low that and air/fuel charge is so sparse that it would not ignite. Your combo would tolerate some different settings but that doesn't mean it should miss, if something like that is happening, misfire would be on aleatory cylinders, not always in the same one.

Otoh, a bad cylinder sealing do to rings or piston failure would produce a concurrent misfire because the low compression present. A simple compression test would discard that.

edit: I want to correct myself here because it is not that it will not ignite, it may ignite but it will not generate enough cylinder pressure to produce the expected move in RPM/torque by the misfire detection logic. Something along this lines.

 

[grabber07]

Could a vacum leak, at the base of the intake manifold, over that cylinder cause this?

 

[grabber07]

http://www.brenspeed.com/02location.html

Well I had this wrong seems to have cleared up so far.Had too many beers to go test it.

Steve

 

[GrnBullitt08]

My car had been running like shit too lately....I have the same problems they mentioned. I need to check this out myself. Thanks for the post.

 

[grabber07]

Well it worked cleared up misfire now I had a p2196 (o2 stuck rich) cleared it,didn't come back but now I have a p2197(o2 stuck lean)Well shit.................at least i cleared misfire

Steve

 

[lito]

Your sensors were right and you turned them around.

 

[wdkingery]

Your sensors were right and you turned them around.

lito you appear to be a smart mother fucker.. you have come back with some valuable insight on this dude's problem, i think.

cheers mate

 

[grabber07]

They were not right according to that picture in the link I posted to.So then I have them backwards

 

[lito]

They were not right according to that picture in the link I posted to.So then I have them backwards

The error they are showing is typical of an inverted sensor, what happens is that it (the PCM) sees a sensor state and acts accordingly, the problems is that it enlean or enrichens the incorrect bank and the initial state just worsen until he reachs the max correction allowed and flags the code on.

For you to be sure which one is either one just unplug one sensor, if the codes thrown (basically heater stuff) show refers to bank 1 that connector (the one unplugged) should be in the passenger side if the codes say bank 2 then in the driver's.

If you have your flasher you can log the heater error flag or o2 voltage and detect it immediately.

 

[grabber07]

Ok do I do this at idle or driving?

 

[lito]

What kind of flasher do you have at hand?

 

[grabber07]

I have sct x3

 

[lito]

send me a PM with your strategy and an email addy and I'll get a file for you to log and what to check.