Another knock question with 786 02s

[jojo]

Kinda funny, took the car out for a blast yesterday, and tried tuning a little. Started off with 16# of boost and ran a WOT and had to let off the throttle as my boost creeped up to 18# in third and looked at the 02s which read 760 or so with spark retard on the scanmaster of about 3.2 or something like that. Turned the rod down one full turn, and tried it again with the boost going up to about 14-15# and creeping once again to almost 17# in third. Let off the gas as the knock gauge started on the first green light then going up a to the third green light. 02s read 769 and spark retard showed 0.9. So i kept it there. This morning on the way to work really confusing i was cruising at about 35mph and punched it to pass the slow pokes and i felt the gear drop down to second real quick as the car pulled, but then i seen the knock gauge quickly go to the second green light, so i let off real quick and checked the scanmaster. 02 were 789 and retard was 2.4 . What is going on? fuel pressure set at about 46-47# line off when i checked when i got to work everything on the car is pretty new pump,hot wire, regulator,fuel filter, ect.. and am running 91 octane right now just confused how i took it for a blast yesterday and left it at 15# with 0.9 retard and today it did what it did. Any good advice or things to check for i appreciate it. Oh sorry for the long thread but i figured you guys would need details to know what to look for

thanks


jojo

 

[jojo]

Forgot to mention i got the knock at the top of second going into third when it hit the second green light on the knock gauge. What is happening here? weather to cold this time of morning? but im running 46-47psi of fuel pressure. I dont get it from yesterdays runs. Just seems a little weird.

thanks

jojo

 

[blackbuick87]

Doesnt matter what FP you run or what your O2's are when you run out of octane. Too much boost for pump gas. Sounds like the wastegate puck may be sticking causing your boost creep

 

[striker_29]

Ok by "spark retard" i guess your talking about knock retard. Or spark advance?? Anyway I guess you mean kr. Your fuel pressure seems high to me, but your o2's dont seem to be indicating that its rich. Do you know if your fuel presure is rising with boost?

Edit: good point by blackbuick87...91 octane

 

[jojo]

Originally posted by blackbuick87
Doesnt matter what FP you run or what your O2's are when you run out of octane. Too much boost for pump gas. Sounds like the wastegate puck may be sticking causing your boost creep

Thanks Black, but why did i get 0.9 retard on the WOT run yesterday from a dead stop? and today i just floored it from 30-35 mph and got 2.4 knock and 02s at 789 at the top of second and going into third?

thanks

jojo

 

[jojo]

Originally posted by striker_29
Ok by "spark retard" i guess your talking about knock retard. Or spark advance?? Anyway I guess you mean kr. Your fuel pressure seems high to me, but your o2's dont seem to be indicating that its rich. Do you know if your fuel presure is rising with boost?

I havent checked that yet Striker, although the pump,regulator,hotwire,inj are all pretty new, and never had this kind of KR before. Could the possibility of like Black said of not enough octane cause this at 15psi of boost? Its like i was saying before though, i took it for a WOT yesterday and 0.9 and 786 on the scanmaster. Seems a little confusing, ive been running 91 octane for about two weeks now and this is the first time this happened

thanks

jojo

 

[striker_29]

Yeah I think its very possible, what kind of gas were you running before??

 

[jojo]

Originally posted by striker_29
Yeah I think its very possible, what kind of gas were you running before??

100 octane

 

[blackbuick87]

Bingo!


Do you know how much timing is in that chip? 15psi max on 91 octane is pretty normal. on 93 the most I could get was 16#.

 

[striker_29]

Well I can get 15 # on 93, but that seems to be pushing it. So I could definately see that being your problem. Of course every car is different. I would try going down to around 13 0r 14 psi, I bet your kr goes away. That or splash in some xylene. Good luck!

 

[jojo]

Originally posted by blackbuick87
Bingo!


Do you know how much timing is in that chip? 15psi max on 91 octane is pretty normal. on 93 the most I could get was 16#.

JL 92 chip with about 18-19* timing in it.

thanks

jojo

 

[jojo]

Originally posted by striker_29
Well I can get 15 # on 93, but that seems to be pushing it. So I could definately see that being your problem. Of course every car is different. I would try going down to around 13 0r 14 psi, I bet your kr goes away. That or splash in some xylene. Good luck!

Man ill tell ya, i loved the 100 octane i was running about 22-23# of boost with 0 KR and 02 at 779 or so. I might go back to running that, because the car loves it but at 3.98 a gallon dammit i go through a tank a week as daily driver.

thanks

jojo