bad low throttle performance
bad low throttle performance I know it is an oxy moron but when throttle is low like cruising maybe 10-15% throttle max my car shudders and shakes. I just got it a few weeks ago and have been fixing countless things. I chalked the bad cruising performance to the cam and would downshift, but after the exhaust is fixed and o2 sensors are replaced and new plugs and wires, oil leaks fixed, I beat on it a bit. I am fairly certain it is a fuel issue. The p0440 code came on, yes the cap is tight and seals properly. I was low on gas, less than a 1/4 a tank but not out like 1/8 of a tank. I took a turn and even with 50-75% throttle I got no acceleration for a seccond then it went. I repeated this to see what it was and the same result. I filled the tank and the cornering issue went away. Easy fix keep it over a 1/4 tank. The low throttle issue is bothering me tho. I have been reading and searching and have found issues in the ballpark but not the same thing. I am still waiting on an email from the guy I bought the car from for an extensive bottom to top rundown of the car on all of the mods. But this is what I can remember
-stroked forged ls1
-bigger injectors
-tuned at RPM( a LS1 Shop in NC)
-high flow fuel pump
-fast 92/92
-lt's
-catted Y pipe
-slp LM1
-zex 100 wet shot, installed not armed or charged
What is the solution, or better yet what could be the cause of the problem expirenced.
-stroked forged ls1
-bigger injectors
-tuned at RPM( a LS1 Shop in NC)
-high flow fuel pump
-fast 92/92
-lt's
-catted Y pipe
-slp LM1
-zex 100 wet shot, installed not armed or charged
What is the solution, or better yet what could be the cause of the problem expirenced.
383ci ls1
K-1 stroker crank
eagle rods
mahle forged pistons
comp cam 242/244 .610/.612 (polluter)
slp heads
high pressure high flow ported oil pump
fast 92 with 102 TB
pace setter long tubes with catted y pipe LLP? and slp LM!
rollmaster double roller timing set
Granatelli 255lph fuel pump with racetronics wiring system
zex nitrous system
freshly rebuilt transmission
monster stage 3 clutch w/ flighwheel
tick master cylinder
subframe connectors
adj. pan hard and rear control arms
the motor, trans, and clutch have 7,000
optima yellow top battery
tuned by Ryan at RPM in Garner NC 456 rwhp with 427 tq
K-1 stroker crank
eagle rods
mahle forged pistons
comp cam 242/244 .610/.612 (polluter)
slp heads
high pressure high flow ported oil pump
fast 92 with 102 TB
pace setter long tubes with catted y pipe LLP? and slp LM!
rollmaster double roller timing set
Granatelli 255lph fuel pump with racetronics wiring system
zex nitrous system
freshly rebuilt transmission
monster stage 3 clutch w/ flighwheel
tick master cylinder
subframe connectors
adj. pan hard and rear control arms
the motor, trans, and clutch have 7,000
optima yellow top battery
tuned by Ryan at RPM in Garner NC 456 rwhp with 427 tq
TECH Senior Member
Joined: Apr 2002
Posts: 6,080
Likes: 17
From: So.Cal.
P0440 means the EVAP plumbing has an air leak... this same airleak makes your engine run lean at low throttle (i.e. the airleak is a significant portion of the airflow into your engine).
Related thread: https://ls1tech.com/forums/general-m...akes-idle.html
Related thread: https://ls1tech.com/forums/general-m...akes-idle.html
I have been talking to the previous owner and he said the surging is the cam and am thinking that is not the answer. I have been trying to find out who else has a big cam like I have in a DD M6 and see if the issue is cam related or if it is another problem that I am having.
It was tuned after the cam. The previous owner thinks it is because of the cam! I called the tuner that tuned the car and described the issues to him. He said that cam is big and isnt very nice to drive low rpm however it shouldnt be bucking as bad as it is. He asked about my fuel pump, I told him it was an aftermarket granatelli unit. He told me to look at the fuel line that the pump connects to in tank. I pulled it out and it was split! Unfortunately on my way home from advance with the fuel line to replace it I blew a tire, the sidewall shot on a sumotumo htr z II so once I fixed it I havent drove yet cause of the spare, but I reset the computer and the engine starts right up instead of cranking for 10 secs then firing. I will drive it down the road with the donut on and see if the problem is fixed.
Got a used tire on till I get the new ones I ordered in, took for a drive and 90 % better. the remaining 10% I can accredit to the cam. The car starts right up and now codes so far! Took it for a ride and threw in 6th at 50, tach read 1100 rpms and no surging or jerking. At 25 in 3rd not alot of surge/jerking. I think this was my fix!
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Got a used tire on till I get the new ones I ordered in, took for a drive and 90 % better. the remaining 10% I can accredit to the cam. The car starts right up and now codes so far! Took it for a ride and threw in 6th at 50, tach read 1100 rpms and no surging or jerking. At 25 in 3rd not alot of surge/jerking. I think this was my fix!