spark at idle jumping
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spark at idle jumping gem 3 5.3 brt stage 3 cam, 799 heads and a "custom tune"
was checking a log and the spark at idle on my truck is all over the board, talking from -10* to +40* of spark advance at idle....
can anyone tell me where the spark should be, how i can start to correct this?
truck runs pretty good, wanting to get stuff dialed in tho i feel there has been a lot left on the table...
was checking a log and the spark at idle on my truck is all over the board, talking from -10* to +40* of spark advance at idle....
can anyone tell me where the spark should be, how i can start to correct this?
truck runs pretty good, wanting to get stuff dialed in tho i feel there has been a lot left on the table...
Launching!
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there are 2 tables. spark idle correction overspeed and spark idle correction underspeed.
they add or subtract timing to maintain desired idle rpm.
when customers ask for a "lumpy" "aggressive" or "cammy" idle a lot of tuners inflate these correction numbers well beyond factory values to create an over exaggerated idle.
overspeed table should have a number like -2 in the first column that's not 0 and taper up to a number like -15
underspeed table should have a number like 2 in the first column that's not 0 and taper up to a number like 15
they add or subtract timing to maintain desired idle rpm.
when customers ask for a "lumpy" "aggressive" or "cammy" idle a lot of tuners inflate these correction numbers well beyond factory values to create an over exaggerated idle.
overspeed table should have a number like -2 in the first column that's not 0 and taper up to a number like -15
underspeed table should have a number like 2 in the first column that's not 0 and taper up to a number like 15
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thanks for the info, I was able to get those along with a lot of other areas changed for the good today..
old tune was really jacked up but its running way better now, sure I've got some dialing in to do still but i feel I am finally headed in the right direction for once since this project got on the road...
I attached my old tune"2018 tune download" and my current from today, if anyone feels like checking them out I'd be glad to hear feedback,,,
THANKS
old tune was really jacked up but its running way better now, sure I've got some dialing in to do still but i feel I am finally headed in the right direction for once since this project got on the road...
I attached my old tune"2018 tune download" and my current from today, if anyone feels like checking them out I'd be glad to hear feedback,,,
THANKS
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O.S vs U.S there are 2 tables. spark idle correction overspeed and spark idle correction underspeed.
they add or subtract timing to maintain desired idle rpm.
when customers ask for a "lumpy" "aggressive" or "cammy" idle a lot of tuners inflate these correction numbers well beyond factory values to create an over exaggerated idle.
overspeed table should have a number like -2 in the first column that's not 0 and taper up to a number like -15
underspeed table should have a number like 2 in the first column that's not 0 and taper up to a number like 15
they add or subtract timing to maintain desired idle rpm.
when customers ask for a "lumpy" "aggressive" or "cammy" idle a lot of tuners inflate these correction numbers well beyond factory values to create an over exaggerated idle.
overspeed table should have a number like -2 in the first column that's not 0 and taper up to a number like -15
underspeed table should have a number like 2 in the first column that's not 0 and taper up to a number like 15
I will have to go in and change those again, as of now one goes to 15 but the other tables set to -35
Just so I know, what would be the effect of those tables be off?
It idles smoother now, but at idle my fuel trims are not within 5%, and I’m also getting a good bit of knock retard that I don’t recall having before.
Launching!
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So the over Speed and under Speed tables need to be the same numbers just one being negatives other positive.
I will have to go in and change those again, as of now one goes to 15 but the other tables set to -35
Just so I know, what would be the effect of those tables be off?
It idles smoother now, but at idle my fuel trims are not within 5%, and I’m also getting a good bit of knock retard that I don’t recall having before.
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it appears my underspeed and overspeed tables are already stock numbers.
Not sure the help I got was all that helpful now! Lol
Obviously I’m in over my head on this tuning deal..
So with that I should pull 20-40% out from stock values?
maybe pull 2 degrees out of the spark table to see if that helps with the knock issue. You seem to have a decent amount of timing in it. Also if you haven't run the current gas out of it, do that and try to get some fuel from a nice new gas station. Ive had the same issue and it was soley a fuel issue that was resolved once I put fresh 93 in it from a diff station. goodluck
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With that cam, you could be running 16 degrees or more at idle--park and idle in the areas where your engine idles(kpa). Your high octane table in the upper rpms and upper airmass should be reduced at least 3 degrees. I believe 26 is too high. You don't need 12 degrees in the low rpm areas of the hi octane table to match your idle tables. go back to a stock looking table in that area. You really need a wideband and post a log of the problem areas. Just changing the tune ***** nilly will get you a broken engine.
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With that cam, you could be running 16 degrees or more at idle--park and idle in the areas where your engine idles(kpa). Your high octane table in the upper rpms and upper airmass should be reduced at least 3 degrees. I believe 26 is too high. You don't need 12 degrees in the low rpm areas of the hi octane table to match your idle tables. go back to a stock looking table in that area. You really need a wideband and post a log of the problem areas. Just changing the tune ***** nilly will get you a broken engine.
I do have a wideband , I’m in the process of getting it hooked up to log through the egr circuit since I don’t own Hptuners pro.
I may just go back back to the original tune file “before the changes this weekend” I posted until I do have the wideband able to data log....
I agree with what everyone else above has told you so far. The timing swinging so wide is a sign that something else is off with the tune. Remember-the PCM is using timing to try and maintain a steady idle. If the engine was idling smoothy with a good VE table, there would be no need for it to add & subtract so much timing.
Here's something I found interesting.. I just checked your RAF #'s against a stock '06 Silvy and your #'s are...... interesting.. Your RAF tables show 20/14 @ operating temp for IN GEAR/Park Neutral.. The factory tune I just checked has #'s in the 5's & 4's for those same operating ranges. If your RAF #'s are that far off, it might explain why the super wide swings in timing.
Here's something I found interesting.. I just checked your RAF #'s against a stock '06 Silvy and your #'s are...... interesting.. Your RAF tables show 20/14 @ operating temp for IN GEAR/Park Neutral.. The factory tune I just checked has #'s in the 5's & 4's for those same operating ranges. If your RAF #'s are that far off, it might explain why the super wide swings in timing.
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I agree with what everyone else above has told you so far. The timing swinging so wide is a sign that something else is off with the tune. Remember-the PCM is using timing to try and maintain a steady idle. If the engine was idling smoothy with a good VE table, there would be no need for it to add & subtract so much timing.
Here's something I found interesting.. I just checked your RAF #'s against a stock '06 Silvy and your #'s are...... interesting.. Your RAF tables show 20/14 @ operating temp for IN GEAR/Park Neutral.. The factory tune I just checked has #'s in the 5's & 4's for those same operating ranges. If your RAF #'s are that far off, it might explain why the super wide swings in timing.
Here's something I found interesting.. I just checked your RAF #'s against a stock '06 Silvy and your #'s are...... interesting.. Your RAF tables show 20/14 @ operating temp for IN GEAR/Park Neutral.. The factory tune I just checked has #'s in the 5's & 4's for those same operating ranges. If your RAF #'s are that far off, it might explain why the super wide swings in timing.
Thread Starter
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Joined: Apr 2018
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I agree with what everyone else above has told you so far. The timing swinging so wide is a sign that something else is off with the tune. Remember-the PCM is using timing to try and maintain a steady idle. If the engine was idling smoothy with a good VE table, there would be no need for it to add & subtract so much timing.
Here's something I found interesting.. I just checked your RAF #'s against a stock '06 Silvy and your #'s are...... interesting.. Your RAF tables show 20/14 @ operating temp for IN GEAR/Park Neutral.. The factory tune I just checked has #'s in the 5's & 4's for those same operating ranges. If your RAF #'s are that far off, it might explain why the super wide swings in timing.
Here's something I found interesting.. I just checked your RAF #'s against a stock '06 Silvy and your #'s are...... interesting.. Your RAF tables show 20/14 @ operating temp for IN GEAR/Park Neutral.. The factory tune I just checked has #'s in the 5's & 4's for those same operating ranges. If your RAF #'s are that far off, it might explain why the super wide swings in timing.