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maybe one of you turbo'd guys might be able to help me out....
man, where do i start...
*long read, sorry, but i figured the more info up front, the better*
ok, here is the main problem i need some advice with.
last night i was scanning my car to see what kind of knock i was getting and noticed that my 1-2 shift was "funny", so i changed around my shift point/rpm ONLY. i was getting a little knock right after the 1-2 shift and sometimes having a commanded shift rpm a lot higher/lower than the command shift mph can cuase this, so i was playing around with that. my commanded mph is 40 and the rpm was 5800, scans show 46mph and 6100 is when the shift is happening! so i lowered the rpm to 5500 which, according to the scans, would be right about where 40mph would be. (stock tranny is 3.33 fdr, current tranny is 3.29, but i dont see how there is that much difference)
after flashing my pcm, i decided to put my MBC back on so i can run 10-12 psi and tune at that psi (i was running 8psi off the wastegate).
before doing any of this, the car felt fine (with the exception of the knock, like 4*, so it wasnt a "major" problem then)
so i flash my computer with the new settings and added back the MBC (i have had this on for a while and never experienced any issues with boost creep or anything)
so here's the new found problem. if i mash the gas, they whole car surges/pulses as it accelerates. the boost gauge doesnt "show" a surging/pulsing of boost, it hits 11psi and stays). never happened before (i was using 1.1.8f until today), if i "ease" into the throttle, the pulse/surge is faintly noticable, however it is MUCH less than if i were to just mash the gas.
im hitting the dyno TODAY after work and i really want to be able to pull at 12 psi, so i need some ideas of what to look at in order to GET to 12 psi.
here are some details of my scans from last night...
the b1s1 o2 sensor (2 months old, A/C Delco brand) reads in the 930mv range with the exception of 1 cell showing a 52mv reading, yes, i said 52mv it was the last cell before it shifted into 2nd, the previous cell was 690, and the previous cells were 930's, (i have ran 880mv's with out knock for months), and then after the shift the cells were 930's and thats when the knock starts.
the wastegate was bought new back in feburary, spring is 8psi. havent had issues with it yet, it is a Tial Sport (not a knockoff)
MBC is a standard brass fitting ball and spring (ive used it to run 12 psi all summer) except for the last few weeks due to turbo problems and having to get another turbo, so i had it running off the wastegate for safety.
i JUST changed my plugs (gapped to .039, stock gap is .060, and i have been running .039 at 12psi without blowout issues), 2 degrees colder than stock on sunday (AL 104's, stock is AL 606).
all vac/boost lines are silcone lines (4mm) and double zip tied or clamped down with extremely small clamps . im almost positive there is not a leak, but you never know and that will be something i check today.
here are a couple other "odd" things that i have seen....
during boost, the b1s1 o2 seems to "glitch" and drop down to a reading of like 52mv, yes, 52mv, no typo. i have seen this happen with other cars with the powertuner, so it could be a "glitch" in the software(?), but i dont know. but for me, it only happened at the 1-2 shift i was speaking of earlier. i have also noticed that it happened again on the way home during a WOT run. but this was in 3rd gear after a downshift from 4th.
after flashing the computer last night, all of a sudden i have a "tick" at light/moderate throttle and as soon as i get into medium boost (5psi+) its no longer audible. it does not do it at idle or full boost (i cant hear it anyway, my car is kinda loud, ) and it does not do it if i put it in N or P and rev it out. only under "load"
so here is what I know i should check for the pulse/surge...
take off MBC, verify it doesnt do it without MBC, if it does not do it, then it has something to do with the MBC or Wastegate.
if it still does it, look at the wastegate, possible rip/tear in the diaphram? i had this happen on my old Deltagate, but it didnt act like this
check tranny fluid level, make sure its correct (im pretty sure its fine, and the tranny holds well IMO, it still breaks loose at the top of 1st and squeels them into 2nd) even with the issues i am currently having, it feels like its holding the power just fine.
check for vac leaks
check turbo and see if the compressor wheel is still intact and not rubbing the housing (im sure thats not it, the turbo is 1 week old today and it does not make any sounds like it wasnt balanced (i call that sound the cat in heat sound).
for the ticking sound....
check oil level (i just changed it last week, could possibly be a little low)
i have installed higher rate springs (ls6 yellow) to eliminate valve float, they are commonly known to "tick" at idle, but i have never heard of them doing it under accelaration.
possibly the vavle seat or valve itselft has been compromised? maybe even the spring seat? but that doesnt explain why it only doest it at certain rpm's and under load.
for the o2 reading of 52mv's....
shit, i have no idea. i have another o2, but its a bosch and i dont like bosch o2's, but i never had an odd reading like that before with the bosch. i may just put that in and see what happens.
add a little fuel and see what happens. i have never had much knock with this car, the GM 60*v6's are pretty knock free and balanced pretty well. the most knock i have ever had was 2* or so, and that was from running really lean, 840mv, and all i did was bump up the fuel and it was fine, never seen knock again.
info about the engine/tranny/turbo. the engine has about 75k and the tranny has about 43k, so they are in fairly good condition. the new turbo was put on last weds, and ran off the wastegate (8psi) until last night and has maybe 400 miles on it.
ANY help, suggestions, comments are welcome.
and if you made it through this whole post and read it, im sorry i had to post the long thread, but i need some thoughts and the more info given up front the better IMO.
so if you did make it to this point and actually post some usefull info, ill buy you a cookie,
thanks!
man, where do i start...
*long read, sorry, but i figured the more info up front, the better*
ok, here is the main problem i need some advice with.
last night i was scanning my car to see what kind of knock i was getting and noticed that my 1-2 shift was "funny", so i changed around my shift point/rpm ONLY. i was getting a little knock right after the 1-2 shift and sometimes having a commanded shift rpm a lot higher/lower than the command shift mph can cuase this, so i was playing around with that. my commanded mph is 40 and the rpm was 5800, scans show 46mph and 6100 is when the shift is happening! so i lowered the rpm to 5500 which, according to the scans, would be right about where 40mph would be. (stock tranny is 3.33 fdr, current tranny is 3.29, but i dont see how there is that much difference)
after flashing my pcm, i decided to put my MBC back on so i can run 10-12 psi and tune at that psi (i was running 8psi off the wastegate).
before doing any of this, the car felt fine (with the exception of the knock, like 4*, so it wasnt a "major" problem then)
so i flash my computer with the new settings and added back the MBC (i have had this on for a while and never experienced any issues with boost creep or anything)
so here's the new found problem. if i mash the gas, they whole car surges/pulses as it accelerates. the boost gauge doesnt "show" a surging/pulsing of boost, it hits 11psi and stays). never happened before (i was using 1.1.8f until today), if i "ease" into the throttle, the pulse/surge is faintly noticable, however it is MUCH less than if i were to just mash the gas.
im hitting the dyno TODAY after work and i really want to be able to pull at 12 psi, so i need some ideas of what to look at in order to GET to 12 psi.
here are some details of my scans from last night...
the b1s1 o2 sensor (2 months old, A/C Delco brand) reads in the 930mv range with the exception of 1 cell showing a 52mv reading, yes, i said 52mv it was the last cell before it shifted into 2nd, the previous cell was 690, and the previous cells were 930's, (i have ran 880mv's with out knock for months), and then after the shift the cells were 930's and thats when the knock starts.
the wastegate was bought new back in feburary, spring is 8psi. havent had issues with it yet, it is a Tial Sport (not a knockoff)
MBC is a standard brass fitting ball and spring (ive used it to run 12 psi all summer) except for the last few weeks due to turbo problems and having to get another turbo, so i had it running off the wastegate for safety.
i JUST changed my plugs (gapped to .039, stock gap is .060, and i have been running .039 at 12psi without blowout issues), 2 degrees colder than stock on sunday (AL 104's, stock is AL 606).
all vac/boost lines are silcone lines (4mm) and double zip tied or clamped down with extremely small clamps . im almost positive there is not a leak, but you never know and that will be something i check today.
here are a couple other "odd" things that i have seen....
during boost, the b1s1 o2 seems to "glitch" and drop down to a reading of like 52mv, yes, 52mv, no typo. i have seen this happen with other cars with the powertuner, so it could be a "glitch" in the software(?), but i dont know. but for me, it only happened at the 1-2 shift i was speaking of earlier. i have also noticed that it happened again on the way home during a WOT run. but this was in 3rd gear after a downshift from 4th.
after flashing the computer last night, all of a sudden i have a "tick" at light/moderate throttle and as soon as i get into medium boost (5psi+) its no longer audible. it does not do it at idle or full boost (i cant hear it anyway, my car is kinda loud, ) and it does not do it if i put it in N or P and rev it out. only under "load"
so here is what I know i should check for the pulse/surge...
take off MBC, verify it doesnt do it without MBC, if it does not do it, then it has something to do with the MBC or Wastegate.
if it still does it, look at the wastegate, possible rip/tear in the diaphram? i had this happen on my old Deltagate, but it didnt act like this
check tranny fluid level, make sure its correct (im pretty sure its fine, and the tranny holds well IMO, it still breaks loose at the top of 1st and squeels them into 2nd) even with the issues i am currently having, it feels like its holding the power just fine.
check for vac leaks
check turbo and see if the compressor wheel is still intact and not rubbing the housing (im sure thats not it, the turbo is 1 week old today and it does not make any sounds like it wasnt balanced (i call that sound the cat in heat sound).
for the ticking sound....
check oil level (i just changed it last week, could possibly be a little low)
i have installed higher rate springs (ls6 yellow) to eliminate valve float, they are commonly known to "tick" at idle, but i have never heard of them doing it under accelaration.
possibly the vavle seat or valve itselft has been compromised? maybe even the spring seat? but that doesnt explain why it only doest it at certain rpm's and under load.
for the o2 reading of 52mv's....
shit, i have no idea. i have another o2, but its a bosch and i dont like bosch o2's, but i never had an odd reading like that before with the bosch. i may just put that in and see what happens.
add a little fuel and see what happens. i have never had much knock with this car, the GM 60*v6's are pretty knock free and balanced pretty well. the most knock i have ever had was 2* or so, and that was from running really lean, 840mv, and all i did was bump up the fuel and it was fine, never seen knock again.
info about the engine/tranny/turbo. the engine has about 75k and the tranny has about 43k, so they are in fairly good condition. the new turbo was put on last weds, and ran off the wastegate (8psi) until last night and has maybe 400 miles on it.
ANY help, suggestions, comments are welcome.
and if you made it through this whole post and read it, im sorry i had to post the long thread, but i need some thoughts and the more info given up front the better IMO.
so if you did make it to this point and actually post some usefull info, ill buy you a cookie,
thanks!
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