vooboo

Ok i might have easy or hard question.. well hard for lots since i am still not able to find the problem after few months and i am sure its easy fix.. i hope i hope i hope..

soo quick run down

87 runner 200 000 kms 22re
no big changes to it.


problem engine light. had it checked. code 12. RPM error

Start up the runner and runs great until i hit 2200 rpms or higher.. Seems every time i hit 22rpm it studers or stumbles a bit and then light comes on.. anytime i am mid way in 2000 rpm i also have loss of power.
things i have changed either before or after this
new plug, wires, distributor, oil filter, gas filter, pc valve
not sure when this started since i started fixing things. so if i caused this or something else 4x4ing. I have since changed the oil again and spark plugs. gave me a bit of power back but could be just me thinking it.
sorry for going on.. i am getting tired of taking it into ty mach.. who just take my money and tell me its something different each time, that doesn`t even help.
Live in edmonton area.

any help would be great.. seeing as my other choice is taking it to dealership and let them play guess``y guess`y at 135$ hour.. and thats just to find problem ..tried this twice allrdy

Keefer

abecedarian

87 code 12 is a knock sensor problem, specifically a lack of signal from the knock sensor to the ECU.
sure you got the code right?

vooboo

I am not sure. 2nd time taking it in.. They couldn't find the codes for that specific year. They only give codes for 89 and said it had same engine.. so gave the code for that one. code 12 = rpm.
so i was reading on about how you can get your own codes by using paper clip or something? is there more details on how you can do this and where i can find out what each code means?

22rEek

I changed the knock sensor and no changes were evident. What now? Just what he said ce light comes on and stutters at 2200 rpm. WWTTFF??

abecedarian

What's the trouble code?
What year? What engine?

22rEek

87 22re 4runner 5 speed.indicates knock sensor code 12.

22rEek

Turns out my motor was knocking. Rebuilding the bottom end now... Knock sensor did its job.

scope103

Uh, maybe.

The knock sensor code does NOT mean "engine is knocking." It means "I advanced the ign timing far enough that it should knock, and I haven't heard anything from the knock sensor. Are you okay?" (The usual cause is a bad connection, not a bad sensor, by the way.)

I don't think that a bottom end rebuilding has anything to do with engine knocking (it might help if you have "rod knock," but that has nothing do with engine knocking or "pre-detonation." )

I'm sure you need the bottom-end job for other reasons, so go at it. And if in the process the knock sensor wiring gets fixed, that will make the code go away. But don't be too surprised if a bottom-end job does not affect your code.

abecedarian

To understand the code, you have to understand how the knock sensor works. It's basically an "microphone" the ECU uses to listen for the sound of pre-ignition caused by whatever. Engine "knock" has certain frequencies it can be heard at, and those frequencies depend a lot on the engine design. The ECU has filters and such within it that reject most of the noises the engine makes, only allowing the frequencies "knock" for that engine occur in. Sometimes, other components can create similarly sounding noises under certain conditions, and that can confuse the ECU, but those are most often caused by a using forged pistons in an engine designed for cast, piston slap, and some other situations I'm not going in to now.

If the knock sensor is working, the ECU removes ignition advance, and doesn't throw a code. You may notice a drop in power when it happens, and you should've heard the knock yourself.

Code 12 for the knock sensor basically means "I'm listening and can't hear you". It does not mean the knock sensor is working.

So, as scope103 said "... don't be too surprised if a bottom-end job does not affect your code."