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87 Octane for 92 Seville?


Caddynut

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Since the gas prices are sky rocketing and I am sick of paying for premium fuel for my Seville, is there any way that I can reprogram the computer to accept a lower octane fuel. I have tried several times to run 87 or even 89 octane and my car just pings like crazy. Maybe I should just let it ping away???? :blink:

2008 BMW 328xi

2007 Chrysler Aspen

2001 Cadillac Seville STS

2000 Ford Ranger XLT
1998 Mitsubishi Spyder Convertible

1996 Saturn SC-1
1991 Ford F-150
1979 Chevrolet Caprice
1968 Ford LTD
1965 VW Beetle "Herbie The Love Bug Replica**

1961 VW Beetle

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Bad idea to let it ping, especially since the 92 does not have a knock sensor. Logan took a couple of degrees of timing out of his 4.9l as I recall to trade some performance for lower octane.

Keep in mind that the difference in price on a FULL tank of gas between premium and regular unleaded is often under $3.

Bruce

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I too have the 92 Seville and I agree with Bruce, don't let it ping.

The 4.9 does NOT have the anti-knock sensor and it's harmful to an engine to allow it to knock. Changing the timing will make the knock go away at the expense of losing performance.

Bruce is right also regarding the price differences of regular and premium. When you consider the harm that can be done to the 4.9, it's not worth it.

Don't be penny wise and dollar foolish although I read an article in the NY Times this morning that said we can expect gas prices to rise to about $3 a gallon by summer.

Parts of California are already paying $2.50 for regular.

If you really want to make people safe drivers again then simply remove all the safety features from cars. No more seat belts, ABS brakes, traction control, air bags or stability control. No more anything. You'll see how quickly people will slow down and once again learn to drive like "normal" humans.

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Because of a lack of a knock sensor, the '92 Seville just isn't going to run well on regular on regular gas no matter what you do.

Really, if you do the math, running regular gas isnt going to save you all that much money anyway. You might save a few dollars a week. Unless you are really driving some serious miles.

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Generally, backing off the timing in a high compression engine (or any engine) will result in poorer performance, poorer gas milage (when pushed), and, because the duration of the burn cycle is the same, but shifted to later, the mixture continues to burn after leaving the cylinder, resulting in the exhaust valves running hotter. Worth it?

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Generally, backing off the timing in a high compression engine (or any engine) will result in poorer performance, poorer gas milage (when pushed), and, because the duration of the burn cycle is the same, but shifted to later, the mixture continues to burn after leaving the cylinder, resulting in the exhaust valves running hotter. Worth it?

The timing can be retarded 3 to 4 degrees - that will allow the use of regular fuel in the 4.9 without spark knock or any damage to the engine. You may notice lower fuel economy/performance.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Thanks, I will just pay the extra and keep my performance....not worth it in the long run.

2008 BMW 328xi

2007 Chrysler Aspen

2001 Cadillac Seville STS

2000 Ford Ranger XLT
1998 Mitsubishi Spyder Convertible

1996 Saturn SC-1
1991 Ford F-150
1979 Chevrolet Caprice
1968 Ford LTD
1965 VW Beetle "Herbie The Love Bug Replica**

1961 VW Beetle

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Guys don't complain up here in Canada i'm paying $4.50 a gallon for premium 94 octane.

I think you might have made a mistake in convertion, careldo. Premium 94 just went up to 86.9c/l here, which is $2.50USD/gallon, much less than the $4.50 you are stating. Unless you live up in the NWT or something, you might try recalculating... :)

1 US gallon = 3.785412 litres

3.785 L * $0.869 CAD/L * $1USD/$1.319CAD = $2.49 USD/gallon

-Chris

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i have used 93 for my 4.9l fpr three years. some sis months ago i accidentally fill it up with 89. surprizingly did not notice any difference neither in performance nor in fuel economy. the engin did not sound different either. could i miss "ping" is it something hard to notice?

The saddest thing in life is wasted talent

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No, it's not hard to notice. When you put your foot in it and the engine is under a load it will sound somewhat like marbles in a coffee can.

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hey guys my 97 STS Knocks even with 97 octane, does my sts have that knock sensor? cause sometimes it would knock then it would stop after a while. and one more thing does your caddi consume oil? i check my oil every month and it seems to be short every time so i add more. i looked at my drive way and there is a oil spot yet when i sit and watch under the car i dont see oil leaking what could be the broblem? and oh yeah bob very detailed and helpful thanx!! :)

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Yes your '97 does have knock sensors and should not be knocking. I won't even try to diagnose that. I'll leave it to some one better qualified.

There is ton's of info in the archives, enough to keep you reading for days regarding oil consumption. One commonly accepted trick is don't keep it at the full mark. If you do your just blowing it out the PCV. Keep it at the add mark and you will probably see your consumption reduce. Mine used a qt every 800-1000 miles til I started putting 7 vs 7 1/2 qts at oil change and adding when it dropped off the dipstick or when the add oil light comes on. I now get 1500-2000 miles per qt. Also give it a dose of WOT once a week. That is supposed to excersise the rings and keep them from carboning up and sticking, allowing more oil consumption.

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you guys are so helpfull. bob the knocking, i can only describe to be like a "knock on the door" with a somewhat of a deep tone i dont know if thats the spark knock or a detonation knock. and where is the knock sensor located? so that i can spot check the sensor itself. oh yeah i did look at the trouble codes and nothing was showing the way you check is when the car is on you press the reset info button right? and pardon me but what is WOT?? this is the first time ive owned a caddi and to tell you guys the truth i LOVE this STS, I live in San Jose, California, and one of the reason i got the STS is because im sick of all the IMPORT racer type i have to admit i was "one" i guess, but anyways it got to a point where i was pulledover once every 2 weeks and checked for engine mods in my prev car, Fawkin got sick of the herassment, and now the caddi, cops dont even look at me any more!! but the girls still do!! LoL.. thanx for the tips folks, ask me anything about Honda/Accura im certified. thanx again.

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WOT = Wide Open Throttle aka WFO ;)

I think you are checking codes wrong if I understood you correctly. On my Deville simultaneously press and hold the off & warmer buttons till all segments of the DIC light up. I think I have heard it said on the seville it is the off & passenger warmer buttons. The stored codes will then be displayed in sequence.

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