Some knock ?s

[Future-GN-Owner]

Alright I bought my GN about a month ago and have changed the plugs, (CR43TS @ .035), wires (MSD 8.8mm), fuel filter (Purolator), and oil (Valvoline 10w30) just so I know everything is in tip top shape. The mods are in the sig and right now it is set at 18-19psi max. My questions is if I roll into WOT I can recall the Scanmaster and its about .800 give or take and usually no knock at all or maybe very little like .9. It seems like when I mash the pedal it stays at 0 for a couple gears then sometimes shoots as high as 39.xx around 3rd so I immediately let off the gas. I have never heard any noises even when registering that high. I have alky and it comes on at about 8-10 psi and the car runs out great and strong (no hesitation or stalling at all). I am trying to figure out what could be causing such a high number. I know there is a little exhaust leak somewhere on the passenger side possibly the manifold and the trans has a nice hard shift. I am still learning but my TPS is set at .42 my BL was at 138 today when I started the car and dropped down to 134 when it was warmed up and I think thats okay. I am just looking for a place to start since I dont want to hurt the car at all. Like I said it runs like a bat out of hell and smooth. I have a new TT chip being burned so I can turn up the boost to 20-23psi but I want to make sure I am not hurting the car before I go any higher with the boost. Also I have a Caspers knock gauge that I plan on wiring in tomorrow hopefully. Any and all help is greatly appreciated and Im sorry for the lengthy post. Matt

 

[Future-GN-Owner]

Also when I see the knock numbers start to jump on the Scanmaster I will let off the gas right away and then that is when I see some of the really high numbers. I only run 93 octane and am currently running the Extender chip that came with the car that is set for the mods. Matt

 

[Future-GN-Owner]

Scanmaster readings at idle warmed up
02 340-630
AF 03
L8 28-30
INT 125-131
BL 136
ATS 81
RPM 800-825
TPS .42
IAC 24
CC 00-245
PL 1.6-1.9
SP 250
Fuel Pressure line on 42psi @ rail line off 48psi @ rail

Hopefully these can help somebody I have been reading up and am learning as I go but am still very green when it somes to TRs.

 

[johnnyttype]

sounds like false knock if it comes on really fast. real knock should progressively increase like 1,3,6,9,13, while false knock might go 3,13,39. hopefully when you get the caspers gauge in it should tell you if there is any real knock to be concerned with.

a banging downpipe or exhaust can cause false knock or a broken engine or trans mount. does the knock occur on a shift?

 

[notacarlo]

For a reference, Knock sounds like a handful of nickles being thrown at your intake manifold.
Due to the repercussions of knock, we all have a fairly good knee-jerk reaction to the sound. Alcohol usually fixes that problem as we all want to turn the wick up and run as much boost as we can on the street for some reason.

The ecm reacts pretty darn quick when the knock sensor starts hearing things and the car will stop pulling as hard. Never the less, when you hear it, help the ecm by lifting as fast as you can.

 

[Future-GN-Owner]

sounds like false knock if it comes on really fast. real knock should progressively increase like 1,3,6,9,13, while false knock might go 3,13,39. hopefully when you get the caspers gauge in it should tell you if there is any real knock to be concerned with.

a banging downpipe or exhaust can cause false knock or a broken engine or trans mount. does the knock occur on a shift?

I dont think it is just at the shifts sometimes it seems to be when I am in 3rd I think. Its hard to tell watching the boost gauge, Scanmaster and RPMs. Also it jumps in huge amounts not slight increases like stated above. When it moves in small amounts it is like .3 .9 and then back to 0. Hopefully it is false knock because I really want to turn the wick up on this thing.

 

[Future-GN-Owner]

For a reference, Knock sounds like a handful of nickles being thrown at your intake manifold.
Due to the repercussions of knock, we all have a fairly good knee-jerk reaction to the sound. Alcohol usually fixes that problem as we all want to turn the wick up and run as much boost as we can on the street for some reason.

The ecm reacts pretty darn quick when the knock sensor starts hearing things and the car will stop pulling as hard. Never the less, when you hear it, help the ecm by lifting as fast as you can.

There is def no nickel type sound (or any metal sound for that matter) when I am getting on it. The worse thing I hear is the slight exhaust leak and thats all and the car pulls hard and smooth there is no hesitation at all. I figured out the alky kit on the car when I purchased it was only spraying about 25% of the time so it ran like crap at WOT the majority of the time. I replaced the whole alky kit with a used kit and have not had that problem since and I know it is working 100% now. I just want to make sure I am not hurting anything before I turn the boost up.

 

["Turbo-T"]

Hey Matt, I may have missed it but when you see knock on the Scanmaster, what kind of 02 mv's are you seeing? From what I've learned when you mash the gas the numbers should shoot up to 800 then taper off to 780, anything lower than 780 get out of the gas.

 

[Future-GN-Owner]

I am watching the knock numbers so much I dont remember what the fuel was at but when I use the recall button on the Scanmaster after seeing a crazy high number it is almost always just over .800 and then knock will be like 39.xx Even when I have a nice smooth run with little or no knock I will recall and the lowest I have ever seen is .780 but usually it is just over .800 which is plenty rich if im correct. Matt

 

[Jerryl]

Scanmaster readings at idle warmed up
02 340-630
AF 03
L8 28-30
INT 125-131
BL 136
ATS 81
RPM 800-825
TPS .42
IAC 24
CC 00-245
PL 1.6-1.9
SP 250
Fuel Pressure line on 42psi @ rail line off 48psi @ rail

Hopefully these can help somebody I have been reading up and am learning as I go but am still very green when it somes to TRs.

IMHO;
Lower the FP to the recomended 43PSi, line off, reset the ECM, get a WB
Previous owner "may" have increased it to compensate for failing alky system, weak pump, bad MAF.
Swap the MAF as the number @ idle is low for the TT chip (If not SD)
Does the FP keep up with boost?

Agree with others;
Typically, the high number is false KR, BUT, it can be real (Could be rich KR)
With that high of a KR, should be audible.

 

[Future-GN-Owner]

IMHO;
Lower the FP to the recomended 43PSi, line off, reset the ECM, get a WB
Previous owner "may" have increased it to compensate for failing alky system, weak pump, bad MAF.
Swap the MAF as the number @ idle is low for the TT chip (If not SD)
Does the FP keep up with boost?

Agree with others;
Typically, the high number is false KR, BUT, it can be real (Could be rich KR)
With that high of a KR, should be audible.

Thanks Jerryl the alky kit was def on its way out when I bought the car so I will try lowering the FP down a little (I assume turning the screw counter clockwise on the regulator) As far as reseting the ECM that is done by unplugging the orange wire right? Does it need to sit for any amount of time? As far as the MAF its an LS1 MAF with translator version 6.21 and what do you mean by SD? Also right now I am still running the Extender chip that was in the car when I purchased it till my TT chip comes in the mail. And as far as fuel pressure it is a gauge on the rail so I cant monitor it but my millivolts are usually .800 or a little higher when running WOT.

 

[Jerryl]

Thanks Jerryl the alky kit was def on its way out when I bought the car so I will try lowering the FP down a little (I assume turning the screw counter clockwise on the regulator) As far as reseting the ECM that is done by unplugging the orange wire right? Does it need to sit for any amount of time? As far as the MAF its an LS1 MAF with translator version 6.21 and what do you mean by SD? Also right now I am still running the Extender chip that was in the car when I purchased it till my TT chip comes in the mail. And as far as fuel pressure it is a gauge on the rail so I cant monitor it but my millivolts are usually .800 or a little higher when running WOT.

OK, the MAF number is correct for the extender.
LS1 is a goof MAF, so, you are good.

FP
Yes, CCW (decreasing spring pressure) will lower the FP.
Pretty sure Bob also recomends 43 PSI, static FP.

Resetting ECM
Yes, unplug the orange wire.
It will rset immediately (I keep it unplugged for 3-5 seconds)

"Trust but always verify".
If someone cranked the FP, I would also question other things.
Make sure the dip switches in the Translator are correct.
Look in sig for KR threads (Just added those "gems" )

 

[Future-GN-Owner]

OK, the MAF number is correct for the extender.
LS1 is a goof MAF, so, you are good.

FP
Yes, CCW (decreasing spring pressure) will lower the FP.
Pretty sure Bob also recomends 43 PSI, static FP.

Resetting ECM
Yes, unplug the orange wire.
It will rset immediately (I keep it unplugged for 3-5 seconds)

"Trust but always verify".
If someone cranked the FP, I would also question other things.
Make sure the dip switches in the Translator are correct.
Look in sig for KR threads (Just added those "gems" )

Already been reading them and learning those are awesome links! I found paperwork for the Extender Chip and it says FP 45psi so I will drop it down and start there and also reset the ECM. I will have to follow the wiring on the MAF and look for the switches while I am out there. Thanks again hopefully some of these steps will help eliminate some of the crazy readings Matt

 

[kenny]

You will have to remove the cover of the Translator to see the switches. Four small phillips head screws.

 

["Turbo-T"]

If you have 780-800 mv's on the Scanmaster and still getting knock, I'd almost be willing to bet it's false knock.

You could always drain the tank and lines and then run nothing but 1 tank of 110 octane and a Razor's alky injection system and see if it still shows knock on the Scanmaster. And make sure the timing is at 20/18. At least this will help determine if you have real knock or not.

 

[Future-GN-Owner]

Okay I took the cover off the translator and the switches are as follows:
1 up
2 up
3 down
4 down
Not sure if thats right I will have to do some more research. Also pumped the FP down to 45psi (line off) and it might be just a coincidence but the idle seemed to smooth out a little. I have the orange wire disconnected right now and in a few I will hook it back up and go for a drive and see if there are any changes. Matt

 

[kenny]

http://www.fullthrottletech.com/attachment.php?attachmentid=582&d=1187014321

Manual for the translator if you need it. I don't remember off hand what the correct setting for a LS1 MAF is.

As for it idling better now, that's probably due to it being hugely rich before whereas now it should be normal.

 

[Future-GN-Owner]

If you have 780-800 mv's on the Scanmaster and still getting knock, I'd almost be willing to bet it's false knock.

You could always drain the tank and lines and then run nothing but 1 tank of 110 octane and a Razor's alky injection system and see if it still shows knock on the Scanmaster. And make sure the timing is at 20/18. At least this will help determine if you have real knock or not.

I checked the Extender chip paperwork and it does not say what the timing is set at so I will have to get ahold of them and see if I can find out. I ordered a TT chip a few days ago since the chips I have are not the newest software so hopefully that will make a difference too. Matt

 

[Future-GN-Owner]

Thanks Kenny I have a binder with all the paperwork, instructions, etc for my GN and this will come in handy. I checked and my switches are set right so thats another plus. I appreciate it. Matt

 

[kenny]

Does the car have stock motor mounts? If so, does it have a ratchet strap from the alternator to the frame?

If not it could be your downpipe tagging the a-arm. Pretty common issue that would cause a reading of 30+

Definitely sounds like false knock.