Knock question .. Scanmaster and Caspers Knock Gauge ...

[Jan Larsson]

Did search and found all the background info etc but still a bit puzzled ..

So I have a scanmaster 2.1 and also the knock gauge AND the audible knock thing both from caspers hooked up on my TTA.

The knock gauge and audible one I have on a switch as I never like ot have them on while driving and rarely do.

Since I built my engine back in 2006 I never had any indication of knock on the SC or any of the casper devices (when I had them switched on).

However took the TTA for a drive earlier today and no knock on the SC at any time even with some mid level boost at times ... switched on the casper knock devices and they seemed to go crazy most of the time ... red - amber and up to red at some points and the audible device bleeping :-( but nothing on the ScanMaster (and it works as all other readings on it seems spot on) ...

So question is have the caspers devices gone bad / crazy and I'm ok as nothing ever showed up on the scanmaster (so no retard at all) ... ??

I know there's issues sometimes with the Caspers devices however as I never had any problems (heck I even thought I migh have had some issues as I never seen any knock so tested the sensor some time ago and all worked fine and I "saw" some knock when I tapped the sensor) up until today when they seem to have gone crazy on my?

 

[TTA308]

Did search and found all the background info etc but still a bit puzzled ..

So I have a scanmaster 2.1 and also the knock gauge AND the audible knock thing both from caspers hooked up on my TTA.

The knock gauge and audible one I have on a switch as I never like ot have them on while driving and rarely do.

Since I built my engine back in 2006 I never had any indication of knock on the SC or any of the casper devices (when I had them switched on).

However took the TTA for a drive earlier today and no knock on the SC at any time even with some mid level boost at times ... switched on the casper knock devices and they seemed to go crazy most of the time ... red - amber and up to red at some points and the audible device bleeping :-( but nothing on the ScanMaster (and it works as all other readings on it seems spot on) ...

So question is have the caspers devices gone bad / crazy and I'm ok as nothing ever showed up on the scanmaster (so no retard at all) ... ??

I know there's issues sometimes with the Caspers devices however as I never had any problems (heck I even thought I migh have had some issues as I never seen any knock so tested the sensor some time ago and all worked fine and I "saw" some knock when I tapped the sensor) up until today when they seem to have gone crazy on my?

Jan i would trust the SM more than the knock sensor, and if you don't have it already the PL is the best thing since sliced bread, i can't believe i let a new PL sit in the closet for over a year....

 

[Jan Larsson]

Thanks yep I would agree the SM would be the most accurate one ... drove it the other day and just had Casper's knock gauge show red once then again when I put it in revers lol ....

Will tap the knock sensor just to make sure the SM do show something .... migh hook up my turbolink as well to make sure everything works ruling out a bad sensor (or SM) ...

 

[larry33kc]

Tap by the sensor not on the sensor. It should show up when doing this.

 

[Street Lethal]

So question is have the caspers devices gone bad / crazy and I'm ok as nothing ever showed up on the scanmaster (so no retard at all) ... ??

If the Caspers sensor is signaling knock w/out being in boost, it might have went bad...

 

[RatFink]

Trash the knock gauge and get a AFR gauge in that spot. Much better.

 

[jarredsoon]

How much boost are you running?

 

[Jan Larsson]

Trash the knock gauge and get a AFR gauge in that spot. Much better.

I think I might look into doing that

 

[Jan Larsson]

How much boost are you running?

Not a lot ... 10 psi +-1 or 2 ... however no knock at boost it's just random really but as I said nothing shows on my SC ... normal bleep on the casper gauges when I start the car then it comes and goes ... last time I took it out it only happened ones or twice and not even under any boost but again the SC showed nothing what so ever at any point not even under boost.

So I think the casper gauges are playing up for some reason.

 

[jarredsoon]

If you have confidence in your fuel system and such low boost I would not be worried. I get knock when my trans shifts gears and I am at 10 vacuum, not even boost. If you"re getting any retard on the scanmaster while WOT or in boost then I would back off and investigate further, if not then carry on.

 

[CGASTON]

Not a lot ... 10 psi +-1 or 2 ... however no knock at boost it's just random really but as I said nothing shows on my SC ... normal bleep on the casper gauges when I start the car then it comes and goes ... last time I took it out it only happened ones or twice and not even under any boost but again the SC showed nothing what so ever at any point not even under boost.

So I think the casper gauges are playing up for some reason.

Jan, make sure that the knock sensor it self is torqued at 14# like it should be. Then I would go from there. Do you have any exhaust leaks?

 

[Jan Larsson]

Jan, make sure that the knock sensor it self is torqued at 14# like it should be. Then I would go from there. Do you have any exhaust leaks?

I'll double check the sensor as well ... fuel pressure should be good but will look at it while driving ... no exhaust leaks that I'aware of but will look at that as well ... my engine is so clean it would show pretty quickly

Thanks for the pointers, much appreciated !

 

[Jan Larsson]

If you have confidence in your fuel system and such low boost I would not be worried. I get knock when my trans shifts gears and I am at 10 vacuum, not even boost. If you"re getting any retard on the scanmaster while WOT or in boost then I would back off and investigate further, if not then carry on.

Fuel should be good but will monitor the pressure while driving and under light boost ...

Still have to make sure my SC picks up on any "knock" from the sensor so I can trust the electronics ... but have had no knock (or retard) show at all since I build the engine 1500 miles or so ago ... only the casper gauges started to show knock very recently ...

 

[CGASTON]

Fuel should be good but will monitor the pressure while driving and under light boost ...

Still have to make sure my SC picks up on any "knock" from the sensor so I can trust the electronics ... but have had no knock (or retard) show at all since I build the engine 1500 miles or so ago ... only the casper gauges started to show knock very recently ...

Does your rockers seem to be louder now? What kind of lifters? BIG QUESTION.... Did you recently change your headers, turbo, or DP? If so I bet we found the problem. Let me know!

 

[Jan Larsson]

Does your rockers seem to be louder now? What kind of lifters? BIG QUESTION.... Did you recently change your headers, turbo, or DP? If so I bet we found the problem. Let me know!

Nope no changes what so ever.

Running Harland Sharp roller rockers, comps roller lifters (and they are quite still lol) and a comp roller cam .... not touched since I built the engine.

 

[TurboBuRick]

Trash the knock gauge and get a AFR gauge in that spot. Much better.

X2

 

[Jan Larsson]

Trash the knock gauge and get a AFR gauge in that spot. Much better.

What AFR do you guys use / recommend ... wideband ? ... where do you mount the additional sensor if running a wideband?

 

[RatFink]

What AFR do you guys use / recommend ... wideband ? ... where do you mount the additional sensor if running a wideband?

I use the AEM afr. I put the sensor near the bottom of the down pipe before where the cat used to be.

 

[jarredsoon]

I use the AEM afr. I put the sensor near the bottom of the down pipe before where the cat used to be.

I use the same. I like it because there is no calibration needed, and it works with a power logger, just let Eric know when he burns your chip. That is if you get a new chip.

 

[WS6]

Still have to make sure my SC picks up on any "knock" from the sensor so I can trust the electronics ... but have had no knock (or retard) show at all since I build the engine 1500 miles or so ago ... only the casper gauges started to show knock very recently ...

Okay... the scanamster only diplays "knock retard" that is being appiled by the ECM and that the knock gauge is actually picking up signal post ESC module. They dont *really* display the same information.

Here's an old thread that explains the difference between the SC and knock gauge....too much for me to retype.

http://www.turbobuick.com/forums/th...-counts-vs-caspers-gauge.276945/#post-2107178


And it's my opinion that at your level you might be better served running a power logger and the scanmaster. This way you can monitor wideband A/F's and KR on the first diplay of the scanmaster. then use the extra gauge pod hole for oil pressure or fuel pressure.

And I couldn't be happier with my switch to a Casper's audible knock detector vs the knock gauge.




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