84CAMARO28inFL

Well my 2.8 Camaro with 164,000 miles -SEEMS- to run better with 93 (or even 89-grade) GAS! I haent had an episode with ti that makes me suspect "Fuel Pump" (Sputtering, hesitiation, not wanting to accelerate) with the higher grades, and i notice a LOT less "Dieseling" (sometimes it used to turn off with a shake, with what sounded like/felt like a few "Fires" of combustion, then shut off. Now it just shuts off, with a varying "shudder" - when i tuern the key off of course - and doe sit less and more mildly, have to be listening for it todetect it.)

Starts up better in the mornings, my Choke is always open (as it should be?) sits warm here so thats ok
And it appears to ened a LOT less "Coaxing" almost none this morning, only one start/die of pumping the pedal, my starter will still "whirr" but if i get right off the key and turn it again it starts...) .. is 93 gas "fixing" my car, please explain some possibles? Thanks!

camaronewbie

Every car I've ever had 'seemed' to run better on higher octane gas. Whether it was real or just a figment of my imagination I don't know. Maybe the sub-conscience wants to believe it, since I'm a tight-wad and spent the extra for the good stuff.

The exception to the rule is motorcycles. I've had several over the last 5 years, none newer than 1995 models, and with all of them they actually ran worse with premium in the tank - they all ran best with just regular old 87 gas - go figure. Guess the smaller engines are more sensitive to changes.

But I have no good technical reasons for you. I could spew out a line of BS if it makes you happy but I'm sure someone else will chime in with a great theory.

Your 'deiseling' issue - usally that's a timing thing. Higher octane gas could possibly burn more (less unburnt fuel) I guess, and so could cut down on the deiseling - I'd check timing and adjust to get rid of the deiseling effect.

firebird904

Your timing is probably off it needs to be at 10* BTDC I noticed my car ran slightly better with 12* BTDC like it pulls a little better from a stop.

TonysBird

Hmm well the higher the octane the harder it is for the fuel to ignite. It is typically known that you shouldn't put any gas that's a higher or a lower octane since it will cause problems. For example: If you put 87 octane in a car that takes 91-93 octane typically it could cause problems such as pre-ignition which is bad.. If you put 91-93 in an 87 octane car then knocking could develop. Either way putting the wrong octane in can/will cause engine damage in the long run (though putting 89 in an 87 isn't really bad). From your issue it sounds like you have a vacuum leak somewhere (the dieseling is a good indicator). I would also check all of the sensors that have to do with fuel/air mixture control..

58mark

iTrader: (3)

I'm going to bump this thread to say that I put premium in my car for the first time yesterday and I was shocked at the results. I've been having a hesitation/stumble issue that's been driving me nuts, but as soon as I put in the premium gas, it went away.

Is that a sign my car is out of time?

RedLeader289

iTrader: (2)

When was the last time your put any kind of fuel treatment/system cleaner through your car? It's possible (depending on the fuel you put in) that the premium had some cleaning/treatment agents in it that fixed an issue.

If you haven't messed with your timing then I doubt that's the issue.

58mark

iTrader: (3)

I do it regularly, like every third or forth tank

One thing that was done was I had a shop change the pickup coil. Removing the distributor shouldn't have changed the timing, should it have? I've taken a distributor out many times and put it right back and I've never needed to mess with timing

RedLeader289

iTrader: (2)

It could have, since turning the distributor is what changes the timing. At least, it seems like a possibility.

58mark

iTrader: (3)

I could mess with it myself, but considering I paid the shop to do the job, I might ask them if they will check the timing

Joe Tag

iTrader: (4)

You can come pretty close marking the position, but it's still advisable to throw a light on it and check.
If you want a real treat, find some pure gas (ethanol free). I did this the other day BC I was going by a place that had some and the difference was night and day within 1/2 mile. Same 90 octane, just not mixed with ethanol. Our cars weren't made to run on todays blends. Not something I'd do regularly cuz it's like 50c more a gallon. But more like eating lobster once in a while instead of steak. puregas.org lists stations in every state and Canada that carry it.

58mark

iTrader: (3)

you might want to check out that link you mentioned.

Joe Tag

iTrader: (4)

For? A little more detailed please?

58mark

iTrader: (3)

just go to it.

Joe Tag

iTrader: (4)

Read fairly extensively the other day before I bought any. Don't beat around the bush, if there's something you feel I missed copy and paste it.

58mark

iTrader: (3)

You go to puregas.org and tell me what you see

Joe Tag

iTrader: (4)

I don't have time for this right now. Going somewhere with the wife. If you want to make a point post it and I'll entertain the idea. Otherwise you are talking in circles.
http://pure-gas.org/index.jsp List of states and provinces at the bottom of the page.

58mark

iTrader: (3)

that's not the link you listed earlier.

RedLeader289

iTrader: (2)

This is true. The second link is much more helpful, amazing what difference a - can make.

Joe Tag

iTrader: (4)

Sorry for that but it wasn't a link I posted, just typed it in. Maybe your browser showed it as one. Google puregas.org and it's the first site on the list.

dmccain

iTrader: (2)

I run 93octane NON-ETHANOL. Runs way better, gets better gas mileage. From what ive been hearing ethanol blend gas really gums up fuel systems. I pay maybe 20 cents more a gallon but its worth it. My other vehicles,tactors, motorcycles, and 4 wheelers are getn it also.

RedLeader289

iTrader: (2)

I run what I can get(as long as it's premium, my engine literally won't run right on anything else), however, I do find it interesting that you guys are getting charged MORE for non-ethanol gas. The stations around here that have it are actually cheaper!