Dana Pereau

Just came back from Master Pechanic at Toyota, who confirmed several things with Toyota and TRD:

1. On the 2002 4Runner, Toyota added several components that prevent reseting the Check Engine Light by pulling the EFI fuse. However, pulling the fuse WILL reset the fuel settings in the computer, so that the computer reestablishes driving patters in conjunction with the grade of fuel used. So for example, if you can't get premium fuel and have to use 87 or 89 octane for a tank or two (ie traveling in Mexico and no 91 available), pull the EFI fuse for 30 seconds during fill up. This will cause the computer to reset the fuel settings, and cause adjustments to help prevent pinging during the time you have to use lower grade fuel.

3. On the 2002 4Runner, the engine computer is much more sensiftive to fuel levels, driving styles, etc. Consequently, it is POSSIBLE, not certain, but possible, that you could run 89 or 87 octane fuel with a supercharger, and never experience ping. Because the 2002 was the last of the 3rd Gen, Toyota will never get a chance to test this through R&D. I have been runnin only 91 octane, but I am going to try several tanks of 89. If no ping, I will drop to 87, and test it there.

Is anyone running 89 or 87 grade fuel in 3rd Gen 4Runners with superchargers?

Gadget

I think what you are going to try is very foolish. Always run the highest grade of fuel availble if you have a supercharger.

If you had an upgraded fuel system and you could richen the mixture under boost, then you could run a lower grade of fuel, maybe.

Jackson Racing who uses Eaton superchargers for their Honda kits has a proceedure for running low grade fuel with their superchargers. This is for times you can not get high grade fuel.

They tell you that with the engine running at idle to use a wire tie and tie the bypass valve on the supercharger in that position. That will lock it in the bypass mode so it can not make high boost and that preven detonation and engine damage.

There was a 4Runner guy on the other board with a latter model 4Runner that was running mid and low grade fuel with his superchager. It cost him an engine overhaul as two pistons failed. The interesting thing is that he said it was not "pinging". I had pictures of his "holed" pistons, but my hard drive failed. They were some impressive pictures. The interesting thing is that the engine still ran with those big holes in the pistons, it just idled rough...

The boost induced high gear/low RPM spark knock is annoying, but it is the detonation that you don't hear at the higher RPMs that will really kill your engine.

It is your truck, and for you to decide, but I would not even think about it.

Gadget

www.GadgetOnline.com

Dana Pereau

I have read everything you have written on the web, and there is no doubt that you have done your homework, and know what you are talking about. It is not worth 5 or 10 cents per gallon (a couple of bucks per fill-up) to take a chance on damaging my engine- I'm going to stick with the 91 octane, and enjoy every wild horse that supercharger let loose under my hood- I have never been so happy with any improvement made to any vehicle, and I am nearly 50 years old, and I have been through at least 25 vehicles in the past 35 years- Thanks for the encouragement not to be a cheapskate, to do the right thing, and to enjoy many years of wild horses under my hood!!

sleepy1405

hey wait...you're supposed to run the premium gas on a supercharged 4runner?! I didn't know that, I think I use plus, well it's called that at Chevron so would that be the 87? It's kinda expensive for the 91 over here, about 10 cents differents I think, almost two dollars per gallon

CTB

Don't you mean two dollars a tank? If you really think about it, that doesn't cost you that much in the long run. Even if you feel up about once a week, that is only 52 weeks * 2 dollars = $104 a year...seems worth it to me

sleepy1405

no what I meant was over here in Hawaii it's almost two dollars a gallon for gas, although the increase will probably be two dollars more per tank, the average price for gas here is getting toward two dollars a gallon, my gas bill is like 26 per fill up