Early Detonation
Le Mans Master
Joined: Jul 2010
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Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
So if it had 14 actual and 12 from KR that means it had a commanded timing of 26*---- BUT I only had 8 programed in !!!!where did the EXTRA
18* come from ????--- It's either a bad ECM or a problem in the knock system---Typically an ECM never works "some of the time or partly"--they either work or they don't--I never suspected the ECM was bad as everything else worked fine--
Long story short--- I suspected he KS's--he replaced them-- brought the car back to me and it responded well to tuning and changes in timing--
This has happened more than just a few times ---at least a dozen --A car or an engine that has been sitting a long time seems to make the sensors go kookoo as well
Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
tblu92,
You know, now that I think about it, when I called him that following Monday to tell him about the idling issue, I asked him if he had turned off the knock sensors since I never got any codes and he response was "no you can't disable them, and wouldn't if you could". Thanks, this may be it, but if he's been in the business for 10 yr's wouldn't he have seen this before now?
You know, now that I think about it, when I called him that following Monday to tell him about the idling issue, I asked him if he had turned off the knock sensors since I never got any codes and he response was "no you can't disable them, and wouldn't if you could". Thanks, this may be it, but if he's been in the business for 10 yr's wouldn't he have seen this before now?
I've never heard of anyone turning off the knock sensors on a DD car-On a decicated race-car maybe yes---
Turning them OFF would gaurantee pinging
And yes with mods and LT's even working knock sensors may act up--But this again is common -but not by adding timing---But by taking too much out--even if you can't hear any audible pinging !!
This is all correctable and almost a MUST on all cam/hds/hdr cars--
You simply need to "desensitze" them The knock sensor tables are massive!!-- apprx 35 different tables and quite complicated--Could be he got them messed up on accident---If you have any way to compare your STOCK tune to what you have now--you can see what they did--Before replacing them--You might try toput ALL the Knock tables back to STOCK to see if anything changes and if it will respond to changes now---
He may have desensitized them too far or simlpy used the wrong tbales for the adjustments---But i find unbelieveable they would let it even out of the shop running the way you say it is---Honestly---The only way I figured
the Knock tables out was thru hours and hours of "trial and error" on my own cars-----------------------
Race Director
Joined: Apr 2007
Posts: 11,150
Likes: 890
From: South Western Ontario
I've had LT1's with failed knock sensors and they just pull timing and run like crap. Haven't seen a LS1 with a failed knock sensor yet.
Thread Starter
Instructor
Joined: Oct 2011
Posts: 108
Likes: 5
From: coastal ME
OK guys what would be my next move, replace the knock sensors or try to find someone who has the experience to troubleshoot what's causing my issues? The tuners web site says they do cams, superchargers, headers and so on but then when I asked him what could cause these issues he said he's not a mechanic but a tuner.
When he first hooked up my car he said somebody hacked the original tune that was in it, but should be able to straighten it out. I'm having a few doubts at this point though.
When he first hooked up my car he said somebody hacked the original tune that was in it, but should be able to straighten it out. I'm having a few doubts at this point though.
Race Director
Joined: Apr 2007
Posts: 11,150
Likes: 890
From: South Western Ontario
I'm kind of on the fence. If the knock sensors do as posted then that could be the issue. But, it also sounds like the tuner isn't very good and that could be the issue. Someone who knows what they're doing should be able to tell you if the timing is right which would rule out the knock sensors.
I really don't think the compression is the problem.
I really don't think the compression is the problem.
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Race Director
Joined: Jun 2009
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RUN that guy is a dam vampire stuck to your wallet.
The guy am going to have my car tuned hits you up for 500 but it takes him all day to tune your car. He does a street, drive-ability and WOT tune for that price, and he will tweak your tune for free if its needed or if you are having tuning issues.
You got hit by an amateur at best. If there are any designated performance shops that deal in LS base model engines I would take it there for a tune.
good luck
The guy am going to have my car tuned hits you up for 500 but it takes him all day to tune your car. He does a street, drive-ability and WOT tune for that price, and he will tweak your tune for free if its needed or if you are having tuning issues.
You got hit by an amateur at best. If there are any designated performance shops that deal in LS base model engines I would take it there for a tune.
good luck
Le Mans Master
Joined: Jul 2010
Posts: 6,005
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Thread Starter
Instructor
Joined: Oct 2011
Posts: 108
Likes: 5
From: coastal ME
Well I'm not sure why I never asked for any advice from someone who lives just a few miles from me if he would be willing to help me out. He has always been into hotrods and currently has an LS1 in his current car. Today I made the call since I didn't want to just start replacing parts that didn't need to be. He said the next nice day to give him a call and he would hook it up and take it for a spin to see what's going on. I will keep all informed what show's up.
Burning Brakes
Joined: Jun 2010
Posts: 812
Likes: 2
From: Metairie Louisiana
I've got a stock 2001 6 speed it's doing the same thing at wot and won't break the tires loose when you roll it to 4000 rpm and mat the throttle in first. Doesn't seem to detonate under accel until wot, tell us what you find out.
Supporting Vendor
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St. Jude Donor '12,'13,'15,'16,'17
Hi Everyone,
I've only only be tuning my own z06 440 ls2 for a yr and feel like I barely scratched the surface of how to tune so bare with me here.
I was tuning in SD mode using HP Tuners and I would make changes to the High/Low octane timing table according to where the scanner table showed knock but the timing wouldn't change. Then my son had a Pro tuner friend of his look at my scan and tune. I'm not exactly sure how he explained it but he said I had to make changes further down the table because I'm in SD. He said if the scan shows knock at say 0.24 g/cyl @ 4K RPM I times the 24 by 2 = 0.48 g/cyl. So I make the timing change at 0.48 g/cyl 4K rpm and it worked. Not sure why its like that but it works. I was having so much trouble with my timing until I found this out.
I've only only be tuning my own z06 440 ls2 for a yr and feel like I barely scratched the surface of how to tune so bare with me here.
I was tuning in SD mode using HP Tuners and I would make changes to the High/Low octane timing table according to where the scanner table showed knock but the timing wouldn't change. Then my son had a Pro tuner friend of his look at my scan and tune. I'm not exactly sure how he explained it but he said I had to make changes further down the table because I'm in SD. He said if the scan shows knock at say 0.24 g/cyl @ 4K RPM I times the 24 by 2 = 0.48 g/cyl. So I make the timing change at 0.48 g/cyl 4K rpm and it worked. Not sure why its like that but it works. I was having so much trouble with my timing until I found this out.
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Thread Starter
Instructor
Joined: Oct 2011
Posts: 108
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From: coastal ME
Well it was not exactly sunny, but I couldn't wait any longer to see what the scan showed from a road test. From what he said all the numbers up to the 5 grand mark looked ok. I'm going to try the race fuel next to see if my compression is just too high. He also said that the knock sensors were reacting as they should.
If I find that the compression is too high I'm not sure of what steps to take next.
If I find that the compression is too high I'm not sure of what steps to take next.
Le Mans Master
Joined: Jul 2010
Posts: 6,005
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Well it was not exactly sunny, but I couldn't wait any longer to see what the scan showed from a road test. From what he said all the numbers up to the 5 grand mark looked ok. I'm going to try the race fuel next to see if my compression is just too high. He also said that the knock sensors were reacting as they should.
If I find that the compression is too high I'm not sure of what steps to take next.
If I find that the compression is too high I'm not sure of what steps to take next.
Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
Hi Everyone,
I've only only be tuning my own z06 440 ls2 for a yr and feel like I barely scratched the surface of how to tune so bare with me here.
I was tuning in SD mode using HP Tuners and I would make changes to the High/Low octane timing table according to where the scanner table showed knock but the timing wouldn't change. Then my son had a Pro tuner friend of his look at my scan and tune. I'm not exactly sure how he explained it but he said I had to make changes further down the table because I'm in SD. He said if the scan shows knock at say 0.24 g/cyl @ 4K RPM I times the 24 by 2 = 0.48 g/cyl. So I make the timing change at 0.48 g/cyl 4K rpm and it worked. Not sure why its like that but it works. I was having so much trouble with my timing until I found this out.
I've only only be tuning my own z06 440 ls2 for a yr and feel like I barely scratched the surface of how to tune so bare with me here.
I was tuning in SD mode using HP Tuners and I would make changes to the High/Low octane timing table according to where the scanner table showed knock but the timing wouldn't change. Then my son had a Pro tuner friend of his look at my scan and tune. I'm not exactly sure how he explained it but he said I had to make changes further down the table because I'm in SD. He said if the scan shows knock at say 0.24 g/cyl @ 4K RPM I times the 24 by 2 = 0.48 g/cyl. So I make the timing change at 0.48 g/cyl 4K rpm and it worked. Not sure why its like that but it works. I was having so much trouble with my timing until I found this out.
The fuel use doesn't double in tandem with the RPM's-- So neither would the KR-----"LOAD" is what triggers detonation-- but the causes can be many ( too lean/too much timing/carbon/etc)These new ECM's use Grams/per cyl but the earlier ones were scaled by MAP -They
really mean the same thing "engine load" The more load--the more fuel--and less timing--RPM's really don't come into play they are on the timing tables but just as a reference to narrow down where on the timing tables you can make changes--- rather than just globally---
A good test I show customers while data logging on an automatic:
Run the car in 4th gear ( un locked TCC) at 40 MPH and note the grams used and RPM--- Lets say it's 1600 RPM at .40 grams
Then shift back to 3rd gear--keep the SPEED at 40 MPH-- and note the RPM's and grams ( will change to apprx. 2000 @ .32 )
EVEN though the RPM's will go up---- the GRAMS of fuel use goes DOWN !!! So its more efficient in 3rd gear than in 4th at that speed--It's because of engine load---There is more load in 4th than in 3rd at the same speed under certain conditions--
Last edited by tblu92; May 11, 2012 at 12:05 PM.
