Misfire, knocking, pinging??

Redog · 12-05-2010, 07:18 PM

Does it mainly when cold.

I'll get on it and it will stumble and the tach goes nuts. I always thought this was a misfire, but now wondering if it's something else.

I use 91 octane, maybe need to go to 93?

P0135 code is on. Need to figure out how to get that light out (it's not the O2 sensor, I replaced that, it's in the programing)

Any ideas:

Newer, plugs, wires, ICM, & coils All about 20,000 miles or less, changing all these didn't make it go away either. Still thinking it's the P0135, but in the programing (HPTuners) I'm kinda lost

Afugy · 12-05-2010, 07:25 PM

Why are you running 91 octane in a non turbo?

12-05-2010, 08:33 PM

Sounds like an electrical short somewhere.

Cliff8928 · 12-06-2010, 01:56 AM

Did you ever disable the AIR system with that other PCM installed?

Redog · 12-06-2010, 03:27 AM

Quote:

Originally Posted by Afugy

Why are you running 91 octane in a non turbo?

It's programed to run on 91 octane

Quote:

Originally Posted by mfuller

Sounds like an electrical short somewhere.

Hmmmmm. wondering where to look first

Quote:

Originally Posted by Cliff8928

Did you ever disable the AIR system with that other PCM installed?

Yes it's disabled. I put in the orginal PCM and the HP tuners wouldn't let me license the PCM

XanderWiFi · 12-06-2010, 07:39 AM

Does it go away when the car warms up?

Someone told me on here once that our pistons will do that until they completely warm up and expand to fill the chamber.

Lucalare · 12-06-2010, 09:26 AM

That would explain the sounds, but not the crazy behavior. Definitely sounds like a short somewhere.

clutch1 · 12-06-2010, 12:27 PM

Check (or get someone to check) the signal from the cam and crank sensors...

Redog · 12-06-2010, 06:28 PM

^^ Good idea
What do you need to check that?

I replaced the crank sensor behind the crank pulley/balancer, somehow half the sensor was ripped out of the block

I forget if that's the 7x or the 24x

Stickybuddz420 · 12-07-2010, 12:09 AM

Quote:

Originally Posted by XanderWiFi

Does it go away when the car warms up?

Someone told me on here once that our pistons will do that until they completely warm up and expand to fill the chamber.

Yeah mine does that slightly, also the exhaust goes put put for a minute then smoke pours and it idles, this is starting in 20- Deg.

clutch1 · 12-07-2010, 12:24 AM

Front one behind the pulley is 24x (24 slots on the pulley, if you look at it), the one on the crank itself is a 7x.

So That was the issue??

[ion] C2 · 12-07-2010, 12:27 AM

Sounds like a vacuum leak..

Quote:

Originally Posted by XanderWiFi

Someone told me on here once that our pistons will do that until they completely warm up and expand to fill the chamber.

Piston slap, I get it since I have forged aluminum pistons in an iron block... different expansions.

Quote:

Originally Posted by Afugy

Why are you running 91 octane in a non turbo?

lolz

Redog · 12-07-2010, 12:27 AM

No, I had that problem in the winter of '10. I could only go 2000 RPM's or the car would give me problems, Translates to 60 MPH max

My exhaust is going put put put too. Now it's starting to do it after it's warmed up

WhiteV6 · 12-07-2010, 12:29 AM

P0135 is not in the programming. You have a short somewhere and its screwing with the computer. If you need help with HPTuners, just email me. Turning off codes isn't going to fix it.

Check the resistance between the PCM connector and the O2 harness connector. Not sure what pins without a wiring diagram but this is what I had to do for a friends achieva that had a #2 cylinder misfire. Bad wire. I couldn't go over 60 mph without it acting like it wanted to break some parts.

Cliff8928 · 12-07-2010, 12:51 AM

Here ya go...

Redog · 12-07-2010, 01:43 AM

That's odd though. I didn't have this probelm with any other PCM I had in the car, just this one. I did swap my stock one back in and I couldn't unlock it with the HPTuners. I figured I could just swap the stock one back in and throw in the program that you already wrote for me and just be done with it.

Is P0135 causing this problem?

Gr1m · 12-07-2010, 02:21 AM

i would get the original PCM in the car that was giving you licensing problems and maybe post up on some forums to figure out what the deal is with that error.

clutch1 · 12-07-2010, 09:44 PM

Ion, it can't be a vacuum leak, vacuum leaks are only at idle, @ speed their effects are negligible at most.

Ken, get someone with an O-scope and monitor voltage on the signal wire of each sensor.. 24x is gonna be a digital (boxes) pattern, and 7x is gonna be an AC waveform... make sure they look legit. Then probably grab a live data scanner and see what the timing advance is... injector pulse, etc... basically any sensors that control driveability.

Like they said, if the comps acting goofy it could be a culprit.

XanderWiFi · 12-08-2010, 10:59 AM

Could it be knocking because of the 91 octane? Stock 3400s are rated to have 87 octane. In Texas they only have 86, 88 and 91 respectively. I noticed that I had knocking with the 86 octane but not when I used the 88. Just a little home experiment. Not sure if it has complete validity though.

Lucalare · 12-08-2010, 11:01 AM

I doubt you would see negative effects (aside from mileage) by buying a higher grade gas. of course there are limitations, I doubt a stock engine would enjoy running 110 or something (airplane fuel).