power loss on lt4 build
Thread Starter
Launching!
Joined: Sep 2009
Posts: 240
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From: 5280
power loss on lt4 build ok so just got my car back together and have a couple kinks that i want some input on.
1. car idles fine till warm then when driving has a hard time staying at idle after foot is released.
2. gets warm around 210 to 230 and really falls on its face around 4500.
the cam is big 240 246 on a 111 so fallin off at 4500 is not right!
and i cant get the damn thing to idle for **** when im drivin it around, it has a tune and the idle screw is all the way out!!!
so should i grab my hpp hand held and go in and set the idle up??
i heard these cars can get air pockets if you fill the coolent up wrong?? is this true? if so how can i fix it cuz it aint geting cooler just jeeps clibming till i have to shut it off, new pump and thermo.
thanks guys
1. car idles fine till warm then when driving has a hard time staying at idle after foot is released.
2. gets warm around 210 to 230 and really falls on its face around 4500.
the cam is big 240 246 on a 111 so fallin off at 4500 is not right!
and i cant get the damn thing to idle for **** when im drivin it around, it has a tune and the idle screw is all the way out!!!
so should i grab my hpp hand held and go in and set the idle up??
i heard these cars can get air pockets if you fill the coolent up wrong?? is this true? if so how can i fix it cuz it aint geting cooler just jeeps clibming till i have to shut it off, new pump and thermo.
thanks guys
Wow, logistics fail.
1) Dont try to tune a build like this with a Hypertech (rolling on floor, seriously).
2) Learn about bleeding the cooling system.
I find it hard to believe you went to the effort to do an "LT4 Build" with a big cam like that and dont even know the importance of properly tuning it or how the cooling system works.
Sheesh
1) Dont try to tune a build like this with a Hypertech (rolling on floor, seriously).
2) Learn about bleeding the cooling system.
I find it hard to believe you went to the effort to do an "LT4 Build" with a big cam like that and dont even know the importance of properly tuning it or how the cooling system works.
Sheesh
This may help your idle issue if you ever get that far... http://www.noid.org/~lj/PCM%20Tutorial/SplitBLMinfo.htm
but it's going to have to be tuned by someone who knows what they're doing in order to idle and run correctly.
but it's going to have to be tuned by someone who knows what they're doing in order to idle and run correctly.
Thread Starter
Launching!
Joined: Sep 2009
Posts: 240
Likes: 0
From: 5280
wow thanks for reading it first, it has been tuned!!!!! and yes on a dyno it runs great for being 8.65:1 comp and no blower yet ran a 12.68 @ 8000 feet corrected and (yes was still getting hot) so dont think im some dumb *** kid that doesnt know his car.
But i keep getting a code of pedal position sensor too low on and off very quickly like comes on i scan it and ten minutes later it goes off but when it comes on thats when it starts to run like crap i know how the damn cooling system works thanks and did the bleeding and a ton of air WAS in the system but every time i check the radiator while its running its still no pressure build up nothing so why cant i get it to "bleed right" usually i get it on the first or second try, but it still gets hot and yes the fans come of like they should when they should!
sorry for asking a dumb question but simple **** like this gets ya the worst.
the 210 230 range i wouldnt think would make it run like 2 cylinders have been choked off, but thats almost what it feels like. it will sit there at that temp and then slowly starts to get hot.
But i keep getting a code of pedal position sensor too low on and off very quickly like comes on i scan it and ten minutes later it goes off but when it comes on thats when it starts to run like crap i know how the damn cooling system works thanks and did the bleeding and a ton of air WAS in the system but every time i check the radiator while its running its still no pressure build up nothing so why cant i get it to "bleed right" usually i get it on the first or second try, but it still gets hot and yes the fans come of like they should when they should!
sorry for asking a dumb question but simple **** like this gets ya the worst.
the 210 230 range i wouldnt think would make it run like 2 cylinders have been choked off, but thats almost what it feels like. it will sit there at that temp and then slowly starts to get hot.
Regardless, the tune is fucked. The "idle screw" on the throttle body being all the way out is your first cue. It's not an "idle screw" the PCM controls the idle via the IAC
Secondly with it "falling off at 4500" again points to the tune.
I'm not sure what method you're using to bleed the cooling system, but you should probably double check it.
Secondly with it "falling off at 4500" again points to the tune.
I'm not sure what method you're using to bleed the cooling system, but you should probably double check it.
Thread Starter
Launching!
Joined: Sep 2009
Posts: 240
Likes: 0
From: 5280
correct but its easier to call it that, but see i dont know any one that will tune an lt car around my nick of the woods so before i moved here i had it tuned. i turned it out to see if it would try to correct for it but no luck of course so its back to where it was.
so when im railin on it i grab third and thats when she kinda just limps out on me almost like if it were being choked. ill try to figure out whats goin on but 3 days ago it was running perfect power wise still getting warm but making damn good power and letting my radials know it. when i had it tuned it made over 450 wheel so i know when its lost power.
if i hop in it and and go its all there till it gets over 210 then thats when you can feel it kinda weaken up top.
so when im railin on it i grab third and thats when she kinda just limps out on me almost like if it were being choked. ill try to figure out whats goin on but 3 days ago it was running perfect power wise still getting warm but making damn good power and letting my radials know it. when i had it tuned it made over 450 wheel so i know when its lost power.
if i hop in it and and go its all there till it gets over 210 then thats when you can feel it kinda weaken up top.
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First off as you know open the bleeder screw for the thermostat, Careful to cover the opti, or at least I do to try and prevent water from getting on it. A full stream must come out, not spurts, rev the motor if you have to, then do the same for the heater bleeder, as far as it falling off at the 4500 rpm level, How? missing, acting like running out of fuel?
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Launching!
Joined: Sep 2009
Posts: 240
Likes: 0
From: 5280
i live now in denver colorado and i have called everywhere looking for lt1 dyno tuning, its all import **** around here or ls1 stuff, closest guy i know is in wyoming so i guess if all else fails ill take it up there. got the bleeding done again today got a full stream no air pockets from 6 bleeds so im hopin i got it this time, and at 4500 yea kinda like it leans way out almost but my fuel pressure stays at around 55 to 60 and the air fuel at WOT is fine doesnt get lean on me, plus i have duel 255's in the back because this thing is getting a blower this winter reasoning for the low *** comp.
