Fuel

I only run 110 octane airplane fuel in mine.

If it's good 'nuff for dem planes, it's good 'nuff for my Yota!

Seriously, can this "Higher octane means higher mileage" myth just die already?

 

Unfortunately that stupid sticker they put on the pumps that says "contains 10% or less ethanol" doesn't really help . And I'm sure the pump clerk wouldn't be able to tell me either. LOL. However, that may be why the price jump here is so ridiculous from 87 to 89. Maybe the 89+ doesn't contain ethanol. Stastically it's still cheaper to run the 10% ethanol at least from studies I've read when compared to the $0.30+ price difference

 

100 avgas is blue in color, its leaded too

 

When I first got my Taco, I ran regular in it from a local Shell station. it was ok, but I did notice a little gas knock under 2000 rpm. Then I bought a tank full of Murphy gas regular and it knocked like crazy. Same with Marathon. It was so bad I put a can of Sea Foam in the tank and the knocking stopped.

Switched to mid grade. Worked ok with Mid Grade Wilco Hess, BP, Shell ( Only with 1 Shell station, another Shell station's mid grade caused knocking). So far my Taco works the best with Exxon mid grade. No knocking.

 

Sounds like your engine is messed up. Shouldn't knock on 87...

 

There is the theory that the EMC retards timing for lower octane fuel. According to the link below, the 5VZ is a 91 octane engine:

http://www.mr2.com/files/mr2/techinfo/Random FSM Data/3vzVS5vz.pdf

As for the 87 rating, many cars will advertise on the lower end of the octane range to appeal to customers

I vote we start a more meaningful thread where ppl use an OBD2 reader to post their timing maps and octane (only if they stay consistent in their octane and haven't reset the ECM lately) so we can lay this bs to rest.

 

According to this link, it's 87.

http://www.toyota.com/t3Portal/document/om/OM35717U/pdf/omsource/1998om/om35717/8.pdf

 

Not really; it actually says "Octane rating 87 or higher" and "research octane number 91" means the engine was tested at 91 octane. Again, check the link I provided on the engine overview. The 5VZ is a 91 octane engine.

If you run 87 octane, the ECM may (or may not) have to retard spark timing compared to 91 octane

I use 89 in the winter and 93 in the summer personally

 

I'm still going to keep using 89.

 

Since I bought the truck, I've used 91, except 1 time. I read all the posts arguing about it. Seemed to make sense that 87 would be okay. So I put a tank of 87 in. And a few times while at a stoplight, the truck sputtered and almost died. When that tank was gone, I went back to 91 and it hasn't happened again.

Could it have just been a coincidental tank of bad gas right at the time I decided to try 87? Maybe. Either way, I'm sticking with 91.

 

89 until I SC the truck, then 91 or 93 (ethanol free)

 

93 octane from day one off the showroom floor . Does higher octane give increased MPG . Doubt it !! Less than 14MPG in town during winter . Engine warm-up and winter blend is most likely blame . 106k and never a miss . Factory plugs until 100k , looked like they would have made 200k without a miss . Have I poured a lot of money down the exhaust pipe ? Maybe ! I don't care , I have never had any problems on late night boat ramps or grouse woods . That's what I pay for , also buy 84 month batteries and replace them every 36-48 months .

 

Been using 87, but started hearing knocking a couple weeks back (8K miles). I'm at sea level and hot weather. Tried 89, not much change. Going to try 91+ non ethanol.

 

Not true at all. "Research Octane" means the octane displayed in other countries outside of the USA.

You're misinformed and wasting money.

 

If the 5vz was an 11:1 motor, yes you should be running hi test. But it is 9.6:1 and doesn't require it. Octane is directly related to comp. ratio to prevent detonation at higher ratios.

 

You would be better served to not use the cheapest brand of fas that is around. A lot of fillers is why it's cheap.

 

Developed sporadic minor knocking on 89, switched to 93 and big difference. Feels like more power and no knocking. I'm still taking it in. It may have a bad spark knock sensor. My research shows it should be able to run 87 with no knocking. But dang I love the performance with 93.

 

Funny i have ran 87 for 256,000 miles on my 5vz but i change spark plugs every 30,000 miles never had a knock...

Maybe some of you guys are running spark plugs too long making the knock or just flooring it all the time..

 

Ive run 87 for 200,000 miles and never had a knock till my spark plugs went bad at 190,000 miles got new ones and its fine again. I didnt know anyone had trouble running 87 haha

 

I use my truck for business, it's a little over 3 months old to me Bought it with 5700 miles on it. I put approx. 3,000 miles on it per mo. and now I'm at 15,000. Still too new for spark plugs to go.