LS1 denotation in low gears only...ideas?
02-28-2013, 07:45 PM
#1
Staging Lane
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LS1 denotation in low gears only...ideas? Hey guys. Just picked up my 1st lsx and got a lil issue. I'm sure I can diagnose it myself but checking with you guys just incase someone has experienced this before.
00 Ws6, P&P LS3 heads, comp xer287hr cam, bluecat tune. At wot it breaks up in 1st and 2nd gear but pulls like a raped ape 3rd and higher. I couldn't imagine the tune being off because Phil is one of the best too say the least and the car runs and idles flawlessly at all other times, doesn't overheat stays around 205-210, starts fast and easy, ect.
Unless there is something rare lsx related that i'm not aware of then i'm sure its something fuel delivery, tune, ignition related. My initial guess is fuel pressure. Would make sense because in higher gears if the pump is weak or there is a restriction it wouldn't be as hard too supply it vs 1st and 2nd. At the same time though it smell quite rich at times. It could be washing the cylinders out.
I will check fp tomorrow and see where that is along with the plugs. May be the pump, fpr, filter, ect. Any ideas? Thanks a bunch guys. Love the car btw. Nice too make the jump from lt1 too ls1
00 Ws6, P&P LS3 heads, comp xer287hr cam, bluecat tune. At wot it breaks up in 1st and 2nd gear but pulls like a raped ape 3rd and higher. I couldn't imagine the tune being off because Phil is one of the best too say the least and the car runs and idles flawlessly at all other times, doesn't overheat stays around 205-210, starts fast and easy, ect.
Unless there is something rare lsx related that i'm not aware of then i'm sure its something fuel delivery, tune, ignition related. My initial guess is fuel pressure. Would make sense because in higher gears if the pump is weak or there is a restriction it wouldn't be as hard too supply it vs 1st and 2nd. At the same time though it smell quite rich at times. It could be washing the cylinders out.
I will check fp tomorrow and see where that is along with the plugs. May be the pump, fpr, filter, ect. Any ideas? Thanks a bunch guys. Love the car btw. Nice too make the jump from lt1 too ls1
02-28-2013, 08:24 PM
#2
Hook a fuel pressure gauge to the rail and tape it to the windshield where you can watch it while driving. Test the car on a safe road and watch if the fuel pressure drops when the engine breaks up.
02-28-2013, 08:55 PM
#3
Staging Lane
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Was also gonna mention I don't see it being a maf or anything else sensor related. #1 I have no codes and #2 if it was something like a maf it should do it it all gears. I also don't see it being anything like grounds, electrical, ect. Once again it would do it all the time if so you would think.
Oh well...can't wait too start the diagnosis tomorrow. Have too get this ole girl right. Made 426whp at bluecat's. Got tars too burn and such. Murica!
02-28-2013, 09:47 PM
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It would not be surprising if you had excess timing or
short fuel in low gears, if you were tuned on rollers that
make the RPMs rise slower than they do on the street.
The MAF especially, lags reality and even SD mode has
some filtering that makes air mass reported, fall behind
air mass actual when RPM is changing fast. So you may
(say) get the fueling for 5000RPM when you're at 5500
climbing fast in first, 5200RPM's fueling at 5500 in 2nd,
climbing a bit slower, 5400's fueling in 3rd... like that.
You may just have to leave a little on the table, to get
ping free across the wider street driving envelope.
short fuel in low gears, if you were tuned on rollers that
make the RPMs rise slower than they do on the street.
The MAF especially, lags reality and even SD mode has
some filtering that makes air mass reported, fall behind
air mass actual when RPM is changing fast. So you may
(say) get the fueling for 5000RPM when you're at 5500
climbing fast in first, 5200RPM's fueling at 5500 in 2nd,
climbing a bit slower, 5400's fueling in 3rd... like that.
You may just have to leave a little on the table, to get
ping free across the wider street driving envelope.
03-01-2013, 08:19 AM
#5
Staging Lane
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It would not be surprising if you had excess timing or
short fuel in low gears, if you were tuned on rollers that
make the RPMs rise slower than they do on the street.
The MAF especially, lags reality and even SD mode has
some filtering that makes air mass reported, fall behind
air mass actual when RPM is changing fast. So you may
(say) get the fueling for 5000RPM when you're at 5500
climbing fast in first, 5200RPM's fueling at 5500 in 2nd,
climbing a bit slower, 5400's fueling in 3rd... like that.
You may just have to leave a little on the table, to get
ping free across the wider street driving envelope.
short fuel in low gears, if you were tuned on rollers that
make the RPMs rise slower than they do on the street.
The MAF especially, lags reality and even SD mode has
some filtering that makes air mass reported, fall behind
air mass actual when RPM is changing fast. So you may
(say) get the fueling for 5000RPM when you're at 5500
climbing fast in first, 5200RPM's fueling at 5500 in 2nd,
climbing a bit slower, 5400's fueling in 3rd... like that.
You may just have to leave a little on the table, to get
ping free across the wider street driving envelope.
03-01-2013, 09:52 AM
#6
Is it def detonation? Besides scanning for kr can you hear it? Mine was very audible, I had a lot of carbon build up. My car; however, pulled clean and held a steady 12.5 afr on motor up to 6500. Engine just sounded bad in spurts.
