Lexmex

I am shocked by the Hess closing, because since I was young and grew up here, that station has always been one of the cheapest for gasoline (it was growing up) and this is a well traveled area of US1. It's actually located on a median between the northbound and southbound lanes of US1 and SW 168th Street.

lexus114

okay,but here is my question re;this.Is their going to be any other physical damage done to the motor say maybe long term by running it with the timing and fuel mixture altered?? I know years ago I would never have dreamed to run any of my motors on any timing other than peak. I.E just before a detonation.

praxis

question.. can different gas octane cause exhaust to change smell? reason i ask.. i noticed a distinct change in exhaust smell (i hope this is not a bad sign, yikes) after i had an after cat o2 sensor replaced. (reference my first posts on this forum and code) also at that same time i began exclusevly running 93 octane. before the "after cat o2 sensor" died, the exhaust had a "sweet" smell to it. it now has a smell like " ashes" or "potash". alkiline i would describe it. has anyone ever noticed this? or has any idea what would cause this.

Lexmex

I don't know why you would have to alter it. Even when I was at high altitude, the vehicle adjusted accordingly (though I still wasn't satisfied (and that went for most other vehicles there in Mexico City). If it's still a stock engine with no modifications, there's really no reason to do this.

Lexmex

Yes, I have noticed different smells at different octane levels (not in my RX) but with my girlfriend's Expedition when we have tried going between 87 and 93.

lexus114

Yeah,I have noticed different smell`s when going from premium to regular.I think it`s normal.Plus with you replacing the lazy sensor,it is burning the fuel differently now.Did you reset your ecm??

lexus114

Hey their Lex,I`m not thinking of trying to advance timing.My question is,by using regular unleaded and the timing adjusts accordingly.Will it have an adverse effect on the engine besides lower mpg,less performance,running a little hotter exhaust temp.?? In other word``s,most people on here according to the poll,use regular w/out any problem`s (according to them) My thought is,will their be a long term affect on the engine?? I.E poss. shorter A/F life,carbon build up,etc?

mikey00

I am now at 150K using 87 octane. I have the same power as premium (as far as I can tell), I get the same MPG (currently 20.1 MPG with AWD and very little highway), plugs came out looking like new (no carbon etc), have never had a valid CEL and have saved over $2,000. At what point do you think this adverse effect will show up 200K?, 300K?, 400K?.

Lexmex

I experimented with regular when I was in Mexico and then again here in Florida. Not happy both times. In Florida, I noticed the power loss when I would accelerate compared to premium, but also did get CELs, but then again my RX has modifications to it.

In Mexico, and the gas is what it is, I noticed a drop in mpg and also poorer performance, but again I also have modifications. There one had higher sulfur.

It's going to depend to on how one drivers, climate and other factors how vehicle will be affected running regular over long haul. My girlfriend runs 87 in her Expedition, has had a few issues (some misfires, pending a/f sensors), but that vehicle seems to run fine on the stuff, but then again she doesn't drive her Expedition like I drive my RX300.

mikey00

I'm in New Jersey so I don't have any of the gas quality or environmental issues that you had. I also don't have any mods and it is my wifes ride so it gets driven pretty easy. I did push it a bit back when I was expirmenting back and forth with different octane levels just to see if I could determine a difference and I couldn't. Now if I had some mods or environmental issues it might be a different story.

lexus114

You also have to give the ecm a chance to adjust itself.

mikey00

I did with both my 2000 RX and 2001 RX. I tested at 3 different points. I first tested immediatly after changing octane levels, then I did a battery disconnect to reset ECM, then tested a third time after ECM adjusted to new octane level. This is with quite a few tanks of each, not just a quick test.

lexus114

I`m at a loss of words here Mik.I can tell you that I notice a big difference in the winter blended fuel vs. the summer blend,Re; 87 octane,meaning when I use 87 in the summer time(due to the prices)once it adjusts it self,it actually runs very well.But when I try and use the winter blend 87,it runs like crap.

praxis

i was under the impression that since it was the "after the cat 02 sensor" it had no bearing on fuel mixture or performance. the sensor i had changed was the one farthest down the line. ie,, after the cat, (the one under the drivers seat and inline the exhause before/near the resonator i think) would that sensor have any effect on exhaust odor? i thought that one was only emissions related. i was told by the lexus dealer that the sensor in question would not affect gas mileage or anything but would only prevent emission inspecion passing for my state/locality. the only code i had was p0136.

it does make sense that different gas blends could cause different odors.


there is ONE thing i can add to the octane discussion. my rx has a lot more "kick" with the higher octane gas. thats all i have to say about that.. lol

mikey00

It was summertime when I was comparing different octane levels. So that may explain some of it.
I run 87 octane year round and haven't noticed a performance difference (winter vs. summer). But maybe I just haven't picked up on it. I wasn't doing a conscious comparison like I was between octane levels. I did notice winter mpg drops off by about 1 mpg. Don’t know if this is due to cold weather, winter blend or a combination.