now i know all cars are different, but this has worked for me. i have stage 2's in my Eco and i would get a CEL if it idled for to long, like more then 10 min. so just for $hits and giggles i put in some 90 octane instead of the usual 87 and 2 tanks of 90 later still no CEL's even after letting it idle while i went in the store shopping for exhaust parts about 20 min. so maybe its worth a shot for some of you others.
hope this helps
04 sunfire auto, mid 15's n/a, and still going
What are these stage two cams you speak of and were can I pick up a set?
Im guessing this is good news???
I hope someone would know this. Since these cams keep the valves open longer, would using higher octane to retard the timing cause it to explode in the cylinder at a better time? Roy isnt the onlt that has said this, but would retarding the timing on the chain and using 87 octane have the same affect as using higher octane? If so, i think it might be a good idea to use adjustable cam gears.
i thought the problem was phantom knock... which was caused by the engine moving from the lope of the cams, not from predetonation...
Roy- I always used the highest octane cause I was running nitrous with the cams, I still got codes regularly
Crackajax- octane rating isn't like reatrding timing, the higher the octane rating the slower the gas actually burns, high cmpression, forced induction, ect.. make for higher cylinder temperatures, if the temp is to high in the cylinder the gas will actuially ignite before the spark plug fires... which is not good, thats detontaion and if it happens while the pistons is still on its way up you could easyily bend a rod/crack a piston ect.. with the higher octane gas its like its less flamable, so where you would get detonation with 87 octane you would not with 90, octane has no affect on the timing its simply to avoid detonation.
strat81- there is more to it then phantom knock, the rough lopey idle makes the computer think the car is detontaing, I insulated the knock sensor and then used 92-93 octane to make sure it wasn't getting actual knock, I still got codes for misfire and to rich, moving the fuel pressure regulator to the intake manifold made the rich codes come alot less often but they still came.... the rich and misfires were both cause from the longer duration of the exhaust and more valve overlap... which means more usable air & fuel makes it into the cylinder (carries out more of the burnt up exhaust, usually some exhaust stays in the cylinder which means less air and fuel can go in) but this also means unburned air and fuel is making it was out the exhaust as well, the 02 sensor sees to much gas and thinks its because of a misfire, same with the rich code
Quote:
Crackajax- octane rating isn't like reatrding timing, the higher the octane rating the slower the gas actually burns, high cmpression, forced induction, ect.. make for higher cylinder temperatures, if the temp is to high in the cylinder the gas will actuially ignite before the spark plug fires... which is not good, thats detontaion and if it happens while the pistons is still on its way up you could easyily bend a rod/crack a piston ect.. with the higher octane gas its like its less flamable, so where you would get detonation with 87 octane you would not with 90, octane has no affect on the timing its simply to avoid detonation.
thanks for clearing that up for me. But why would higher octane work with the cams. Its the same compression and everything. I will need some more aggressive cams and this seems to be a cure for some people, but high octane might be a problem when upping the compression. If it needs higher octane now, higher compression would need race gas, wouldnt it. There must be a better way to run w/ no cel and 87 octane.
maybe the higher octane/slower burning gas makes it idle just alittle bit smother... enough to where the computer is happy? I don't know I couldn't tell ya
yea im not exactly sure why its working im on my 3rd tank of 90 octane and still no CEL and no noticable loss or gain in performance but yes the idle is alot better over all. my cams are the JBP ones and maybe, like you said Darkstars, the cams you had were a longer duration and not as much lift, and possible mine are a big lift and not as much of a duration causing the difference. id really like to hook up a tech 2 and see what is happening.
04 sunfire auto, mid 15's n/a, and still going
Before I wrecked my womans EcoTec, we ran nothing but midgrade in it, and it got better gas mileage, and ran better then with the 87 oct. The engine does have 10:1 compression.
Not sure why you guys have such problems with bigger cams, since the Eco Developers said that thats what the weak point of the engine was......... (long story, but was told this @ the '01 bash)..... Maybe they rigged it
Good luck guys.
SPD RCR Z -
'02 Z24 420whp
SLO GOAT -
'04 GTO 305whp
W41 BOI -
'78 Buick Opel Isuzu W41 Swap
what do you mean the cams are the weak point? So the developers knew this?
weird
That was their reason to why a 10:1 compression motor only produced 140hp,150lb trq....... their answer "We went conservative on the cams, it will benefit from larger cams"
SPD RCR Z -
'02 Z24 420whp
SLO GOAT -
'04 GTO 305whp
W41 BOI -
'78 Buick Opel Isuzu W41 Swap
a reflash of the pcm i would think is the only way of getting around this and j body performance does this now i believe
1989 Turbo Trans Am #82, 2007 Cobalt SS G85
jbp? where to get them?
2004 Cavalier, 2.2 ecotec, 5spd getrag
Jenny Black Thunder WILL Conquer All!!!!
they have a website they are located in ON, canada
1989 Turbo Trans Am #82, 2007 Cobalt SS G85
I have yet to hear of anyone actually getting their reflash done, let alone with good results. I looked into it, but they seemed rather vague and uncertain about PCM tuning, it kinda scared me..
they scare me to on that issue.
and an update ive gone through almost 4 tanks of 90 octane or about 1200 miles and no CEL's still, and i havent cleared any codes the CEL went out on its own after the higher octane my car must be an oddball
04 sunfire auto, mid 15's n/a, and still going
