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biminiLX said:
Laura, I agree.
One thing you mentioned was the computer using the knock sensor. From what I believe I understand the Ford EEC-IV also 'learns' from the driver and condition, so if you run with higher octane and can utilize the higher timing curves w/o detonation, the car will have a more aggresive tune as a baseline. At least that's how I interpretted it :shrug: ...
-J
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EEC-IV is a great automotive computer system. One of the best ever devised. So good, in fact, that it was in use from about 1984 all the way through 1995 with little change.

As with most all automotive computer systems, including OBD-II, they don't make changes instantly, so you're right about the car having to learn about what is happening -- what kind of fuel is being used, what the driver's intentions are, etc. All of this is in addition to the standard stoichiometric tables and knock sensor timing programming, etc.

Stylin55 oh said:
...94...if nothing else it makes me feel like the car is happier
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The ol' butt dyno is probably just in your head. Once you hit 91, that's pretty much all she wrote. However, I'll be the first to say that a clean car is good for 10 horse, and that's probably the same effect that's in play with regard to your fuel comment. :cool:
 
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Thinking the car has more power, etc, from running 94 instead of 91, is purely psychological. Same with washing the car and thinking it runs better.
 
SVTC1136 said:
I just noticed a gas station near my house has "outblaze" gas at 7 bucks a gallon. Soon enough I am going to have to stop in and see what they claim it does.
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Empty your wallet.:shrug: PCM isn't tuned for anything better so it's a waste.
 
todras said:
Empty your wallet.:shrug: PCM isn't tuned for anything better so it's a waste.
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To be clear, I never said I was going to buy any, I just want to see what its supposed do. Unless it makes my bed and does my laundry I can't see myself blowing 80 bucks on a fill up. Heck, I could go down to TJ and get a good hooker for that.
 
i have a 97 2.5L non svt and i put in 87 and get 20 mpg but when i put 89 i get 25mpg......wtf is up with that, exact same driving habits(pedal to the floor) since 87 is $2.95 and 89 is $3.00, i go ahead and opt to spent the extra $0.85 to fill up

this is Shell gas, the only gas i buy, curious to see what 93 will do for me, but not for $3.25 a gallon
 
ok, im a big dummy. when i drove my car to ADC to get it tuned, i filled up with 87 for the loooong drive. i still had some left in the tank when it got tuned. i didnt even think about that. keith told me he tuned it according to whatever was in the tank. he said it would only be 1 or 2 hp difference. besides that, i dont know if i should be putting in 87 nor or 91. am i waisting cash by putting in 91? :confused:

eventually when i add some form of FI to the car, it will be retuned. probably by Nautilus :cool:
 
svt4stv said:
ok, im a big dummy. when i drove my car to ADC to get it tuned, i filled up with 87 for the loooong drive. i still had some left in the tank when it got tuned. i didnt even think about that. keith told me he tuned it according to whatever was in the tank. he said it would only be 1 or 2 hp difference. besides that, i dont know if i should be putting in 87 nor or 91. am i waisting cash by putting in 91? :confused:

eventually when i add some form of FI to the car, it will be retuned. probably by Nautilus :cool:
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The car doesn't change the spark advance, etc. the moment the fuel changes. It takes some time for the car to learn what is going on, so a tank of 87 quickly followed by a tank of 91 would not effect the desired changes immediately. As you drive the car, it will learn -- most adaptations should happen pretty quickly, but they might take a tank of fuel. If the car is now tuned to run on 87 gas, then you may well be wasting money by going up the octane ladder. And as you know, any sort of FI will pretty much require the use of premium, so your tune at that point will be designed to take advantage of the extra spark advance allowed by the resistance to detonation of 91 octane.
 
The only times my tours needed anything over the 87 is when I had manifold leaks or bad injectors. If you plan on keeping the car a long time replace ALL the injectors if you find one bad one because they will all go within a year or so. AutoPartsNetwork sells rebuilt injectors (they look new and I believe they are) for around 40 bucks each. I was surprised how many problems went away when I replaced them. Knocking, rough idle, misfires, various codes to name a few. The coils go bad and too much fuel injector cleaner will ruin the coils too.
 
Out here we have 91 as the highest.....Been running that in the Tour since I bought three years ago...My others cars I run just 87 octane.....
 
Laura - your spark advance statement is only partially correct. Reason being is If an ECU hears a knock it will retard instantly, and revert back to the the curve under the previous learn cycle. If it does not hear a knock it will advance. What the ECU does do under driving conditions and learn mode is tailor the fuel and spark curve based on sensor input for normal operation.

Some are getting confused based on the responses. SVT's require premium, and NON SVT's require 87.
 
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Kevinm said:
Laura - your spark advance statement is only partially correct. Reason being is If an ECU hears a knock it will retard instantly, and revert back to the the curve under the previous learn cycle. If it does not hear a knock it will advance. What the ECU does do under driving conditions and learn mode is tailor the fuel and spark curve based on sensor input for normal operation.

Some are getting confused based on the responses. SVT's require premium, and NON SVT's require 87.
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Previous posts dicsussed the knock sensor's involvement, and how the computer will push spark advance out to the point where trace knock is detected, then back off slightly to achieve an optimal running condition, etc. Don't know if you read those, but your statement agrees with them.
 
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