Fuel Injector Balancing
 

Hey, everyone,

My dad has a 1986 Toyota 4Runner he's owned since it was new, and it has about 115,000 km as of a few days ago.

The reason for the low mileage is that for a long time, he really never drove it, and now, it typically does winter duty, or, if my parents go camping. For that reason, it has absolutely no rust, and, he's babied it, so it still runs very well.

We live in Ottawa, and him and my mother just got back from about a 3,000km trip in it, which, according to him, the truck ran extremely well. The truck has never really had any severe issues, as everything has been kept in check.

He's an older guy, and doesn't exactly care about the negligeable performance the 4-cylinder 22RE has to begin with, so he doesn't particularly care about my the issue I have for you guys, but, maybe you can help.

I remember years ago, on pretty well any road, if you floored the truck, it would rev right up to its redline of around 6000 rpm, and would shift right around there.

Now, when floored from a stop, for example, the truck will upshift at around 4500 - 4800 rpm, and that's really all it seems to like to do. Say you're driving around 80 km/h (around 50 mph), and you floor it, it will downshift a gear or two, but will be turning only around 3800 rpm, and obviously could downshift another gear.

I know this truck is very old, and this problem has been around for at least two years, if I can recall, so it's not something that's just cropped up recently. Before this huge trip my parents went on, my dad went crazy changing all sorts of parts on the truck -- plugs, cap, rotor, fuel filter, etc (even though they didn't need it). The plug wires are still originals, but, my dad claims he did a resistance test, and they were within specification as per the service manual. I told him I'd replace them, but, he didn't bother. The truck's timing seems fine, and starts great with no problems.

The truck has an automatic transmission, which is part of the issue, as it could be the computer telling the truck to upshift at an absolutely retarded RPM (I believe peak torque on the 22RE is 4800 RPM).

Considering the truck had, until around 2002, only been driven about 5000 km a year, I wouldn't think it would be impossible to think some bad gas could have caused the fuel injectors to become imbalanced, or, at least, after 20 years, make them have an improper spray pattern. Since as far as I can remember, I've always noticed, when pulling the plugs, that cylinder number 4's plug reads very rich.

Basically, I don't see why the truck shouldn't rev all the way up to redline, or be able to downshift into a better gear, to make use of its powerband, for climbing hills and such. The truck was never fast by any means, but, I think it's stupid to not be able to use what power it should have. Oh, and we get about 400-450 km out of a tank, I estimate (it's never really run with less than a half a tank in it).

If you guys have had some experience with injector balancing, know of some good shops, or, have some other suggestions for things to check, I would greatly appreciate it, to help my dad.

Thanks a lot,
Yusuf