Experience with detonation….

[J-Rod76]

I think I’m either experiencing detonation or I have a cat that has gone bad.

My mods are: 6lb lower, MAFia, TR6 plugs, Predator flash tuner with standard canned tune for 91 octane, Volant CAI on a 2001 L.

My problem: When accelerating at WOT, after the truck shifts and as the RPMs are on the way back down I hear what I can only describe as a rattling noise coming from what sounds like the drivers side of the truck. The first time I heard it I let off immediately, but since then the truck has done it several more times and the last few times I just accelerated through it.

Other than the rattle, the truck runs perfectly. Any ideas?:shrug:

 

[bonehead]

yeah, thats bad. id check your truck with a scanner to see if the knock sensor has been going nuts. check engine light on?

 

[bgstew6]

we dont have knock sensors....the harmonics from the SC mess with a knock sensor and would make it retard timing so we dont have them...next time you have the lower intake manifold off...LOL....look there on top of the valley (where it should be but isnt)

when did it start..how long you been running this setup and tune....is it the first time?

could be a bad tank of gas...cplugs could be worn out so you could check the plugs to..IF the tune is new it could be in the tune

 

[J-Rod76]

No check engine or SES light. I've been through more than one tank of gas, but I haven't pulled the plugs yet as they are only about 6 months old. I've been running this setup for about 6 months.

 

[bonehead]

ummmm, yeah. i have a knock sensor in my valley, ive seen the input for it and watched it on a star tester.

 

[bgstew6]

soory bout that Boner dont even ask me what i was smoking....

WE have them...but they arent used by the PCM to retard timing....

SHeesh....having one of those days.LOL

 

[pitstain]

read my sig........have nightmares

 

[bonehead]

soory bout that Boner dont even ask me what i was smoking....

WE have them...but they arent used by the PCM to retard timing....

SHeesh....having one of those days.LOL

LOL. i hear ya. what retards timing then? it has to have some kind of safety precaution.

 

[bgstew6]

IAT2 temps....I know will....as soon as they start cresting 150 then the retarding commences....after that it grows pretty exponentially.....had a chart let me see if I can find it..

 

[bonehead]

i did not know that. told you i was an idiot. but if the IAT is fine and you accidentally just filled up with 87 ( cuz you just smoked a huge j 30 min prior) and the thing is pinging its brains out, and your still completely baked, then what?

 

[bgstew6]

LOL BOOM

going off of memory here now as I cant find my chart that I copied...

but it starts at 150...at around 180 you are in safe mode and I think its back to 0 then over that around 200 its actually like -5.

guys have blown a motor up running 87oct and foot in the floor or shitty tank of gas and foot in the floor.....

 

[Kryo-Genik]

Experience with detonation….

Yeah plenty...

in my case the check engine light came on but it made NO sound NO rattle..nothing. Only thing I felt was the truck kind of stutter and that was it.
a week later I got my truck back.
But the above wasnt fromt he 6# and canned predator tune...it was the
95mm MAF that wasn't adjusted for.

 

[bonehead]

Yeah plenty...

in my case the check engine light came on but it made NO sound NO rattle..nothing. Only thing I felt was the truck kind of stutter and that was it.
a week later I got my truck back.
But the above wasnt fromt he 6# and canned predator tune...it was the
95mm MAF that wasn't adjusted for.

i told ya! i hate canned tunes and i hate pump gas!

 

[bonehead]

LOL BOOM

going off of memory here now as I cant find my chart that I copied...

but it starts at 150...at around 180 you are in safe mode and I think its back to 0 then over that around 200 its actually like -5.

guys have blown a motor up running 87oct and foot in the floor or shitty tank of gas and foot in the floor.....

you didnt really answer my question. there has to be an anti knock system. the whole reason for computer controlled vehicles is for emissions. if a motor is pinging, its not burning all the fuel, hince greater emissions. there has to be something to retard timing besides the IAT. if the PCM didnt use the knock sensor, what is there for? not trying to clown you, just wondering if you have an answer i dont know about.

 

[Fade 2 Black]

There is NOTHING to control knock on our trucks. They will detonate given the circumstance and if you don't hear it (most times you won't) it will promptly destroy plugs, head gaskets or throw rods.

Pinging, detonation and preignition are not all interchangeable and not necessarily the same thing.

If you pump lower grade gas in you need to either add enough octane booster to make it safe, take the s/c belt off and drive the gas out or drain and refill the tank with 93.

Stock timing (spark) tables are written to be safe from detonating with proper octane, the only other factor then is heat from boost which will cause detonation/preignition. This is why the IAT2 temp setting causes the PCM to retard spark. Most of the time all you'll ever hear is moderate throttle pinging caused by old plugs or bad gas-I've had it. At WOT the peripheral noises will mask the sounds of detonation (unless the engine is almost completely stock as well as the exhaust).

I could go on and on.....

 

[J-Rod76]

Ok, so maybe I got some bad fuel or perhaps my plugs need changed out. What do I need to do, other than be careful where I get my gas, to prevent this from continuing to happen? If I'm not mistaken, the TR6's I have in there now are gapped at .036. Also, is there anything I can pull from data logging with the Predator that might indicate detonation?

 

[bmfgsxr]

change your fuel filter too.

 

[bonehead]

Ok, so maybe I got some bad fuel or perhaps my plugs need changed out. What do I need to do, other than be careful where I get my gas, to prevent this from continuing to happen? If I'm not mistaken, the TR6's I have in there now are gapped at .036. Also, is there anything I can pull from data logging with the Predator that might indicate detonation?

the best experience that ive had with pump gas is chevron if youre out west. if youre back east, sonoco or bp sells 93. most sonocos carry 95 as well. gap wont promote ping, however, if your running alot of boost, id close the gap a little bit. im not familiar with the data logging on the predator, im sure some of these other guys are though, somebody should chime in by the end of the day.

 

[wydopnthrtl]

I'd suggest rulling out the cause otherwise you'll continue to be in the dark about it.

Make the fuel in the tank have a definate excessive octane. Go get some 100octane and put enough into the tank to have a 50/50 mix. Give it a few mile to mix well then repeat your WOT shift/knock situation.

If it's gone.. then you know for sure what it was/is. If it's still there.. then you know it's something less serious.

Rich

 

[J-Rod76]

I don't think it is the fuel because I have gone through several tanks and this problem hasn't gone away. I’m changing out the plugs and fuel filter tomorrow. I wanted to change out the plugs before I went to the dyno anyway, and the fuel filter has not been changed since I’ve owned the truck (The truck has 54K on the clock and I bought it with 26K).

With the mods that I have listed, what is the best gap for my plugs?

93 octane isn't available here unfortuniatly, so I may run down and put some 100 octane in it to give the 50/50 mix a try.