Would fuel hurt the timing of a car?
- Thread starter firemandan1700
- Start date
one thing i've noticed is that too rich of a pe table (base or rpmvstime) has been causing kr in some recent tunes since when you go into pe it mask's the true maf tuning esp in the upper ranges
by doing the maf tuning with pe disabled (much like ve tuning) youll notice that it will add (fuel) in the upper ranges of the maf table once it gets down to the ltft's being within 3% the kr goes down a damn good bit (except shifts)...you may notice that after that type of maf tuning when pe is reinstated you will notice more kr from being too rich to diag this take the pe base af and return it to stock (from say a dhp 1.5 file) or even rais it to 13 to 1 and after a quick jaunt it'll give you a good idea whether kr decreases... al's current bin file has the base pe af set to 12.4 and the pe rpmvs time table halved... since then he's added 2* and now only gets shift kr
while pe disabled maf tuning is unorthodox it makes sense in that when you go into pe fuel trim learning is practically disabled and your just not getting good data.
you will notice that you get Kr (try to make sure you stay under ~5*) during the initial no pe maf tuning but if you look at the scan data and check the ltft's at the higher ranges (2nd and 3rd gear slow windouts help ya get the upper ranges) you can extrapolate to the end of the maf table reflash and continue...as your higher range ltft's get near zero youll see you kr decrease dramatically...
the other thing to remember here folks is that 4th gear isnt for tuning...it's for fuel economy...if your kr is rampant while in 4th gear DONT get on it in 4th gear even if you do and force the downshift to 3rd that spike in kr will affect your spark tuning massivly (darkshadow, edsel, al and eric have all seen this as i demonstrated it to them) what this means is that in some area's you just cant change the tune to get rid of kr, you have to change you driving habits....if you having fun around town and speeds below 60mph....keep it in 3rd use 4th for what it was intended... highway fuel economy/cruise
it's far better to manually downshift into 3rd at 60mph and get on it than to stay in 4th and gun it....
by all means dont take my word for it....it's easy enough for ya'll to see for yourselves.... just add current gear to your logs
by doing the maf tuning with pe disabled (much like ve tuning) youll notice that it will add (fuel) in the upper ranges of the maf table once it gets down to the ltft's being within 3% the kr goes down a damn good bit (except shifts)...you may notice that after that type of maf tuning when pe is reinstated you will notice more kr from being too rich to diag this take the pe base af and return it to stock (from say a dhp 1.5 file) or even rais it to 13 to 1 and after a quick jaunt it'll give you a good idea whether kr decreases... al's current bin file has the base pe af set to 12.4 and the pe rpmvs time table halved... since then he's added 2* and now only gets shift kr
while pe disabled maf tuning is unorthodox it makes sense in that when you go into pe fuel trim learning is practically disabled and your just not getting good data.
you will notice that you get Kr (try to make sure you stay under ~5*) during the initial no pe maf tuning but if you look at the scan data and check the ltft's at the higher ranges (2nd and 3rd gear slow windouts help ya get the upper ranges) you can extrapolate to the end of the maf table reflash and continue...as your higher range ltft's get near zero youll see you kr decrease dramatically...
the other thing to remember here folks is that 4th gear isnt for tuning...it's for fuel economy...if your kr is rampant while in 4th gear DONT get on it in 4th gear even if you do and force the downshift to 3rd that spike in kr will affect your spark tuning massivly (darkshadow, edsel, al and eric have all seen this as i demonstrated it to them) what this means is that in some area's you just cant change the tune to get rid of kr, you have to change you driving habits....if you having fun around town and speeds below 60mph....keep it in 3rd use 4th for what it was intended... highway fuel economy/cruise
it's far better to manually downshift into 3rd at 60mph and get on it than to stay in 4th and gun it....
by all means dont take my word for it....it's easy enough for ya'll to see for yourselves.... just add current gear to your logs
the 3.8 is on it
Well I wanna kill this tank of gas I have now and put 93 octane from somewhere else in it. If that doesnt work I will pull the battery plug.
I really never thought of what shell added in there gas would make that much of a difference...
Car seems to run fine for normal driving. I put a new filter on last year. Plugs are about a year old. I need to pull them and check the gap thought. (yearly routine)
Well I put in 93 octane from another gas station and i maybe got a half degree more timing.
I went and unplugged my PCM for an hour per Ron Vogel and I went for a drive and I got 15* for about a second or two and then dropped back down to 12-13. I still have 0KR too.
I know a wideband is a must at this point.
I am hoping to get back out and scan again this week when its dry and nice.
Im scratching my head here. I am in the process in aquiring an HPT. So we shall see...
Do you think the highflow cat could be bad. I bought it used.. How do you tell a cat is bad? Should I just hollow it out and say screw it? lol
I went and unplugged my PCM for an hour per Ron Vogel and I went for a drive and I got 15* for about a second or two and then dropped back down to 12-13. I still have 0KR too.
I know a wideband is a must at this point.
I am hoping to get back out and scan again this week when its dry and nice.
Im scratching my head here. I am in the process in aquiring an HPT. So we shall see...
Do you think the highflow cat could be bad. I bought it used.. How do you tell a cat is bad? Should I just hollow it out and say screw it? lol
If you are going togo through the trouble of checking the gap, just change them.
Good point. They are cheap enough. Any suggestions? Ive tried autolite 104s and champions version of the autolite 104. I didnt see a difference.
Is there something else I should try?
I can vouch for this scenario. If I want to gun it on the highway while in 4th, I give it about 40% throttle which causes the TC to unlock, down shift into 3rd and then I go WOT. Depending on my speed, it will downshift again into 2nd. I never go WOT in 4th.
lol
Thread Info
-
Created -
28Replies
-
784Views
-
Participants list
