LS1 bogs when shifts into 2nd gear at WOT - Pirate4x4.Com : 4x4 and Off-Road Forum

prostock3 · 04-27-2010, 06:54 AM

Ok i have a ls1 factory computer and such. My issue is when im at WOT it runs strong in first gear all the way to redline, and when it shifts into second its bogs really bad and feels like its missing. Its not a traction controll issue since this motor is in a buggy and all that stuff has been removed. The motor now if i come off the gas and floor it after its doing this will run fine. It has k&n airfilter, and block hugger heads, it does run o2 sensor and mass air flow. Fuel pressure is correct and it does have new spark plugs. Any ideas?
trans is 4l60e

florida4x4 · 04-27-2010, 12:00 PM

Do you have any way to log the fuel, timing and O2? kinda hard to make any judgements without it.

Bo185 · 04-27-2010, 02:40 PM

Plus, what RPM is redline?

Any SES lights?

Blackdog76 · 04-27-2010, 09:30 PM

My K5 does that when it's low on fuel. I have a huge 31 gallon tank and if I take a corner fast or accel fast and it's low on fuel that always happens to me. Gen III's love lots of fuel and lots of fuel pressure. I have a Walbro 255 that helps things along.

Rinkrat456 · 04-27-2010, 10:07 PM

For diagnostic purposes, could you turn off DFCO if it isn't already?

How are the spark tables between shifts?

Is all TQ management disabled?

Falling on it's face between shifts is usually spark related, however the statement you said about fuel pressure being correct made me wonder how you know that? How was this pressure tested? (I ask because I had plenty of pressure at idle but at WOT only 36psi = bad pump and too small injectors)

prostock3 · 04-28-2010, 06:53 AM

Ill get a fuel gauge on it again, shouldnt it be around 50-60psi? what is DFCO? the computer was done by jims performance

Rinkrat456 · 04-28-2010, 09:03 AM

DFCO is fuel management between shifts. Fuel pressure in the upper 50's at WOT is best. My factory pump is rated at 62.4PSI at 34.5GPM. At WOT it doesn't drop below 58psi.

04-27-2010, 06:54 AM	#1 (permalink)
prostock3 Registered User Join Date: Dec 2005 Member # 62903 Location: Mich Posts: 517	LS1 bogs when shifts into 2nd gear at WOT Ok i have a ls1 factory computer and such. My issue is when im at WOT it runs strong in first gear all the way to redline, and when it shifts into second its bogs really bad and feels like its missing. Its not a traction controll issue since this motor is in a buggy and all that stuff has been removed. The motor now if i come off the gas and floor it after its doing this will run fine. It has k&n airfilter, and block hugger heads, it does run o2 sensor and mass air flow. Fuel pressure is correct and it does have new spark plugs. Any ideas? trans is 4l60e __________________ 2009 Twisted Customs buggy (sold :C) -----2001 Donzi 38zx -----2004 Duramax 2500 CC

04-27-2010, 12:00 PM	#2 (permalink)
florida4x4 Beaver Pleaser Join Date: Sep 2002 Member # 13645 Location: home of the wayward dirt bike Posts: 1,419 Blog Entries: 1	Do you have any way to log the fuel, timing and O2? kinda hard to make any judgements without it. __________________ 1972 GMC Submarine 383 / TH350 / 203D-NP205 / D60 / 14FF / 42's on Stazworks / heavy foote / four eyez Inclined to brute force attack a 70* incline with a Quadrajet 1997 GMC K3500 Suburban 454 / 4L80E / HP60 SAS / PROJECT TOWHOE

04-27-2010, 02:40 PM	#3 (permalink)
Bo185 Vortec Scout II Join Date: Jun 2005 Member # 48545 Location: Arkansas / "The Stan" Posts: 3,598 Blog Entries: 1	Plus, what RPM is redline? Any SES lights? __________________ '73 Scout II Vortec 6.0L 4L65e np241 '73 1210 Travelette SV392, T-34, 60/14bff 4.56's 35's '01 VW Beetle TDI-50mpg or better! GM Gen III/IV V8 swap info TECH: Gen III/IV "LS motor" to Early GM Auto Trans

04-27-2010, 10:07 PM	#5 (permalink)
Rinkrat456 Registered User Join Date: Mar 2007 Member # 88919 Posts: 757	For diagnostic purposes, could you turn off DFCO if it isn't already? How are the spark tables between shifts? Is all TQ management disabled? Falling on it's face between shifts is usually spark related, however the statement you said about fuel pressure being correct made me wonder how you know that? How was this pressure tested? (I ask because I had plenty of pressure at idle but at WOT only 36psi = bad pump and too small injectors) __________________ [COLOR="Lime"][I]At 1300rpm's would you rather have 10 extra hp or 10 extra lb-ft of torque?[/I][/COLOR]

04-28-2010, 06:53 AM	#6 (permalink)
prostock3 Registered User Join Date: Dec 2005 Member # 62903 Location: Mich Posts: 517	Ill get a fuel gauge on it again, shouldnt it be around 50-60psi? what is DFCO? the computer was done by jims performance __________________ 2009 Twisted Customs buggy (sold :C) -----2001 Donzi 38zx -----2004 Duramax 2500 CC

04-27-2010, 09:30 PM	#4 (permalink)
Blackdog76 Registered User Join Date: Oct 2002 Member # 14187 Location: San Rafael CA Posts: 839	My K5 does that when it's low on fuel. I have a huge 31 gallon tank and if I take a corner fast or accel fast and it's low on fuel that always happens to me. Gen III's love lots of fuel and lots of fuel pressure. I have a Walbro 255 that helps things along.

04-28-2010, 09:03 AM	#7 (permalink)
Rinkrat456 Registered User Join Date: Mar 2007 Member # 88919 Posts: 757	DFCO is fuel management between shifts. Fuel pressure in the upper 50's at WOT is best. My factory pump is rated at 62.4PSI at 34.5GPM. At WOT it doesn't drop below 58psi. __________________ [COLOR="Lime"][I]At 1300rpm's would you rather have 10 extra hp or 10 extra lb-ft of torque?[/I][/COLOR]

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