Dignan

1988 4 runner 22RE 5spd 197K Rebuild at 176K

First note, I haven't noticed anything wrong with my Runner until just the other night.
Two days ago I drove to some firework stands about 10 mins from my house to meet some friends. I made the trip there with no problems what so ever. I stayed there for a little over an hour to BS with my friends and decided to head out. I proceeded to turn my key and nothing happened. I tried numerous more times with still no crank. After an attempted jumpstart, still no help (battery not dead). So in annoyance I got some people to help me compression start it in which it fired right up. The problem is, the check engine light turned on and the fan seemed like it was spinning like a bat out of hell for the first 2 mins it ran. I decided to follow my friends home and it seemed also like it was lacking some power, especially at higher RPM's. Also at idle it ran much quiter then I was used to. After the 10min drive home I parked, opened the hood and the exhaust header looked to be slightly glowing orange (very hot). At that point I was thinking that I was getting detonation (causing lack of power and hot exhaust) but I made sure the engine temp guage never said anything higher then normal. I still have not figured out the entire culprit, but after reading quite a few tutorials I learned to read the OBD codes. It came up with code 12 and 51.

Code 12 - If the ECU doesn't register RPM's within 2 seconds of the start position being used.

Code 51 - One of three sensors is having an error, neutral safety, A/C, and Throttle position sensor.

The first one is obvious because it wouldn't crank the starter and all you heared was one "click" per turn to start.
The second code bothered me because since I dont' have an automatic, I don't have a neutral safety switch and I also don't have A/C. The only thing left is the TPS, and I don't understand how that could break at the exact same time.

So my questions are these.

1) How reliable are the engine codes?
2) Is it just the silinoid contacts are broken? I have gone through a couple starters and none just quit instantly, they all slowly died so I wasn't sure.
3) What could cause the TPS error at the same time?
4) Is there anything else you need to know or I need to check?
5) On a scale of 1-10 how much of a PITA is changing out the starter?

HondaTec521

I'd take a close look at your TPS,it sounds like you were running way lean(orange ex.,lack of power.
The starter is a pain ,being under the intake manifold.But before you change it ,test it.(apply batt.voltage to the starter activator terminal-it should crank if the starters ok)
For both problems to occur at the same is unlikely,but not impossible.You could have one failure causing both problems(wiring harness-overcharging/undercharging alt.,ignition switch............)

JoKEpLaYeR

Weird.... my starter wouldn't turn over the other day, I replaced the starter and now i'm getting a error code 51.... how odd. I tried to adjust the TPS and the 2nd and 3rd positions aren't doing what they are supposed to do. I'm going to replace it.