need tips on spark tuning...
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From: stop the fun suckers
Re: (scorp508)
yea.. well thats the weird thing... I VEmastered my fuel tables and found that it added fuel to the low RPM, load load cruise areas and subtracted fuel from the high rpm/high load areas.. all this after taking a bunch of timing out of the high load/high RPM areas and only taking 2-5* or timing out at low load/low rpm... so it doesnt make sense.. why does it need more fuel at low rpm with less timing?
Also, if I assume the tables are VE tables like they are labeled... since i could pump more fuel in at higher spark levels in high RPM/high load conditions with the increased spark advanced does that mean it made more power up there? I'm going on the assumption more fuel='s the engine was getting more air.. since more air ='s more power the high the VE numbers that are generated that would seem to equate to more power?! right?
Also, if I assume the tables are VE tables like they are labeled... since i could pump more fuel in at higher spark levels in high RPM/high load conditions with the increased spark advanced does that mean it made more power up there? I'm going on the assumption more fuel='s the engine was getting more air.. since more air ='s more power the high the VE numbers that are generated that would seem to equate to more power?! right?
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From: stop the fun suckers
Re: (BluByU)
ok.. ***update**
Last night I ran three diffrent programs.. each time I took out roughly 2* of spark at cruise location (1400-2400rpm/ 35-55 Kpa) and of course smoothed the transitions between that and the rest of the table.. anyhow.. I noticed no improvment or worsining of the condition.. the car stayed about the same? :confused: so I put the orig. spark tables back in.... now what? I'm thinking of changing the fuel filter.. however, I suspect if the filter was plugged I would be getting odd Lterm and or Sterm #'s and I'm not.. I also decided its not the A/C compressor because i flet it last night while the a/c was off..
Ohh.. I also turned out all the lights in the garage with the engine running (a bit un-nearving). After my eyes adjusted to the darkness I could see the plug wires.. they like GLOW! they weren't arching.. but dam where they glowing.. they are brand new (maybe 3000 miles) is this normal? I know arching is bad.. but blue glowing the whole length of the wires? every wire?!
Last night I ran three diffrent programs.. each time I took out roughly 2* of spark at cruise location (1400-2400rpm/ 35-55 Kpa) and of course smoothed the transitions between that and the rest of the table.. anyhow.. I noticed no improvment or worsining of the condition.. the car stayed about the same? :confused: so I put the orig. spark tables back in.... now what? I'm thinking of changing the fuel filter.. however, I suspect if the filter was plugged I would be getting odd Lterm and or Sterm #'s and I'm not.. I also decided its not the A/C compressor because i flet it last night while the a/c was off..
Ohh.. I also turned out all the lights in the garage with the engine running (a bit un-nearving). After my eyes adjusted to the darkness I could see the plug wires.. they like GLOW! they weren't arching.. but dam where they glowing.. they are brand new (maybe 3000 miles) is this normal? I know arching is bad.. but blue glowing the whole length of the wires? every wire?!
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From: Texas
Re: (BluByU)
ok.. ***update**
Last night I ran three diffrent programs.. each time I took out roughly 2* of spark at cruise location (1400-2400rpm/ 35-55 Kpa) and of course smoothed the transitions between that and the rest of the table.. anyhow.. I noticed no improvment or worsining of the condition.. the car stayed about the same? :confused: so I put the orig. spark tables back in.... now what? I'm thinking of changing the fuel filter.. however, I suspect if the filter was plugged I would be getting odd Lterm and or Sterm #'s and I'm not.. I also decided its not the A/C compressor because i flet it last night while the a/c was off..
Ohh.. I also turned out all the lights in the garage with the engine running (a bit un-nearving). After my eyes adjusted to the darkness I could see the plug wires.. they like GLOW! they weren't arching.. but dam where they glowing.. they are brand new (maybe 3000 miles) is this normal? I know arching is bad.. but blue glowing the whole length of the wires? every wire?!
Last night I ran three diffrent programs.. each time I took out roughly 2* of spark at cruise location (1400-2400rpm/ 35-55 Kpa) and of course smoothed the transitions between that and the rest of the table.. anyhow.. I noticed no improvment or worsining of the condition.. the car stayed about the same? :confused: so I put the orig. spark tables back in.... now what? I'm thinking of changing the fuel filter.. however, I suspect if the filter was plugged I would be getting odd Lterm and or Sterm #'s and I'm not.. I also decided its not the A/C compressor because i flet it last night while the a/c was off..
Ohh.. I also turned out all the lights in the garage with the engine running (a bit un-nearving). After my eyes adjusted to the darkness I could see the plug wires.. they like GLOW! they weren't arching.. but dam where they glowing.. they are brand new (maybe 3000 miles) is this normal? I know arching is bad.. but blue glowing the whole length of the wires? every wire?!
The glow around the wires is normal. All have it to some extent.
[Modified by 96GS#007, 11:25 AM 1/23/2004]
Thread Starter
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From: stop the fun suckers
Re: (96GS#007)
ok.. i'll try the advancing it a 2* intervals now... would that make sense with the speed of the piston increasing/length of time at TDC decreasing (my stroker vs. stock parameters)?
Also, this happens at speeds below TC lockup as well.. 30-45mph it happens.. shoot, it even happens at 15-20mph if i go that slow.. :cry
Also, this happens at speeds below TC lockup as well.. 30-45mph it happens.. shoot, it even happens at 15-20mph if i go that slow.. :cry
Thread Starter
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From: stop the fun suckers
Re: (96GS#007)
could you explain it for me.. I think i understand but maybe i'm missing something.. if the surge is caused by some air being pushed back into the intake from the chamber due to duration wouldn't cams with more duration less lift than mine cam (like the hot cam) experiance this problem even more than me? and if thats what i'm battling how does the spark timing help? i'm confused.. again.. :( :banghead:
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From: Texas
Re: (BluByU)
could you explain it for me.. I think i understand but maybe i'm missing something.. if the surge is caused by some air being pushed back into the intake from the chamber due to duration wouldn't cams with more duration less lift than mine cam (like the hot cam) experiance this problem even more than me? and if thats what i'm battling how does the spark timing help? i'm confused.. again.. :( :banghead:
By adjusting the timing, you're trying to optimize the ignition of the fuel mixture. When optimized, surge will be minimized. Depending on engine specifics and the starting point for the timing map, some engines need more timing, others less.
Thread Starter
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From: stop the fun suckers
Re: (96GS#007)
ok, i tried adding 2* of advance and no-joy... crap!! I datalogged it and while driving i foudn the place where it felt surge at a few diffrent points... what i noticed was it usually occured when the AC compressor was pumping up.. causing a shift in the MPA vs. RPM spark graph.. anyhow cruise Kpa is around 45-55 kpa and when i felt surge the only diffrence in the datalog was the spark.. by a mesly 1*.. anyhjow i made all the 45-60 Kpa range's the same at any given RPM and it seemed to help alot... i never knew the car could beso sensitive to 1 losuy degree....problem still isnt gone.. but is minimized! ill keep you posted!
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Joined: Apr 2001
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From: Dallas TX
Re: (BluByU)
Hmm.. good info here. Now that I've got the LT4 running again I have to figure out how to get my spark tables all fixed up. I'm starting with a stock LT4 table. Took it for the first drive and it tried to die everytime i took off in 1st. I think I need a lot more spark in the low rpm - higher MAP area's.
[Modified by GlockLT4, 7:14 PM 1/24/2004]
[Modified by GlockLT4, 7:14 PM 1/24/2004]
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From: Texas
Re: (GlockLT4)
Hmm.. good info here. Now that I've got the LT4 running again I have to figure out how to get my spark tables all fixed up. I'm starting with a stock LT4 table. Took it for the first drive and it tried to die everytime i took off in 1st. I think I need a lot more spark in the low rpm - higher MAP area's.
[Modified by GlockLT4, 7:14 PM 1/24/2004]
[Modified by GlockLT4, 7:14 PM 1/24/2004]
Team Owner
Joined: Apr 2001
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From: Dallas TX
Re: (96GS#007)
Be sure to check your fuel trims and get those squared away before messing with the timing. Other than Closed Throttle Spark Advance my timing tables are virtually untouched except in a few cells around the 1500-2000rpm / 45-55 kPa cruise areas and at high load / WOT.
I tried using the sample table that Jim had.. and it helped a little but not enough. So... i found this on my computer from when i worked with the 383.
So i took that and decided to add a bunch to the high kpa low rpm areas and this is what i'm going to try out:
Team Owner
Joined: Apr 2001
Posts: 22,267
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From: Dallas TX
Re: (GlockLT4)
Ok, that last table worked a little better for taking off in first ... BUT there is a big hesitation in 2nd gear around 2k rpm... so what about this:
Is this too agressive for lower rpm's?
[Modified by GlockLT4, 3:54 PM 1/25/2004]
Is this too agressive for lower rpm's?
[Modified by GlockLT4, 3:54 PM 1/25/2004]
Thread Starter
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Joined: Nov 2000
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From: stop the fun suckers
Re: (GlockLT4)
update to my surging problem.. Started a new thread in tech.. I'm thinking maybe I have a mechanical problem/incompatability not nessesarily a tunning issue.. check here please.. I could really use your help and thoughts.. http://forums.corvetteforum.com/zerothread?id=740023
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From: Texas
Re: (GlockLT4)
.
Just an opinion, no hard data, but I think that'd be about as far as I would go with the advance at low rpm/high kPa. Too much advance burns valves
Ok, that last table worked a little better for taking off in first ... BUT there is a big hesitation in 2nd gear around 2k rpm... so what about this:
Race Director
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From: Texas
Re: (BluByU)
update to my surging problem.. Started a new thread in tech.. I'm thinking maybe I have a mechanical problem/incompatability not nessesarily a tunning issue.. check here please.. I could really use your help and thoughts.. http://forums.corvetteforum.com/zerothread?id=740023
Going thru a datalog record by record isn't value added for tuning, but for diagnostics it can help. When I logged data and the miss would occur I would occasionally see it as a slight drop in the rpms, load (kPa), and in my case MAF g/sec for a record or two....literally a blip in time. The log file wouldn't always catch it (my miss was above 6000rpm at WOT) but it was there sometimes. Might be worth checking.
FWIW, when my second Opti went (I'm on #3), the miss was at low rpms and sometimes was a hard miss and sometimes was a soft bucking. Never had any codes.
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From: stop the fun suckers
Re: (96GS#007)
I noticed Tech I's can display the high res and low res signal.. I wish datamaster could pick it up.. Im thinking about just replacing the cap and rotor on the opti-crap... I wish I could test it before i did that... how did you come to the determination that your opti-crap has blow out?? Maybe time to go to LTCC conversion..
I just hate throwing money at something I',m not sure will solve the problem..
[Modified by BluByU, 7:25 AM 1/28/2004]
I just hate throwing money at something I',m not sure will solve the problem..
[Modified by BluByU, 7:25 AM 1/28/2004]
Race Director
Joined: Apr 2000
Posts: 15,344
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From: Texas
Re: (BluByU)
I noticed Tech I's can display the high res and low res signal.. I wish datamaster could pick it up.. Im thinking about just replacing the cap and rotor on the opti-crap... I wish I could test it before i did that... how did you come to the determination that your opti-crap has blow out?? Maybe time to go to LTCC conversion..
I just hate throwing money at something I',m not sure will solve the problem..
I just hate throwing money at something I',m not sure will solve the problem..
Thread Starter
Race Director
Joined: Nov 2000
Posts: 17,103
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From: stop the fun suckers
Re: (96GS#007)
This feels more like a soft miss.. is subtle.. not abrubt.. My fuel filter change last night didnt solve the problem but reduced it alot! I still cant figure it out.. :cuss
