need help 89 4runner

pops and hesitates/no power tps checked ok mass air flow tested ok is a 22re the motor purrs at a idle try to give it gas and pops through the air tube and falls on its face. pulled codes has a 51 switch signal the book states ac switch checked/tested ok then TPS checked/tested ok then says ECM cant find any diagnostics test for the ecm.so i am stuck there and the only other thing i noticed during my diagnostics is the knock sensor is not hooked up so i got the sensor and there is no spot on this block that it will fit.so i plugged it in and grounded it no change in runability.so i dont know wich direction to go the book has no ecm diagnostics test,and the block has no spot for the knock sensor/would the knock sensor even cause that kind of problem.if anyone can give any suggestions/ideas would greatly appreciate she"s no good sitting thanks

Knock shouldn't cause that particular problem.

Has it always ran this way, or did it just start?

Have you checked the timing, plugs, wires, firing order, fuel filter, fuel pressure?

timing is dead on,fuel pressure tested good.the 4runner did not run before .had bad engine so i dropped 1 in .since it has ran i cant get the code 51 to clear wich i think is the trouble runs perfect at a idle.when i clear the code it runs exellent then the light comes on back to popping.the only test i have not done is testing the ECM my manual does not have any ecm tests.any suggestions.and i called toyota to get a scematic for testing the ecm/wiring they said its to old.i asked what if i brought it to them they told me they would not touch it due to being over 10 years old i guess toyota dealerships dont know how to work on there old stuff (thats sad)so now i am at stand still unless someone can help.any help appreciated thanks

Well, I can get you any specific scematic or diagram you need. Just be specific on what you want.

Also, code 51 is not stored in the ECM memory.

ECU Pin-Out Tests
http://i132.photobucket.com/albums/q30/kbruington/tech/41752856.gif

hey thanks for the print that will help.if you can get any schematic whats the chance of the diagnostics schematic for the code 51.the book says switch code thats it.if it is not a stored code then why when i clear it it comes back almost as fast as i clear it.and i can only clear by my scanner will not clear disconnecting the battery for 30sec.i really appreciate the help its been down for a couple months.the manual i have is a haynes (it sucks) is it possible to get the proper tps settings from you. the book had me do three steps with a fealer guage but when i set the ohms for the 3rd step it would throw the first step out of specs.it could be the tps with the popping symtem but the haynes book shows those 3 steps and then says it is set.like i said earlier runs perfect at idle under load hesitates and pops.tested mass air flow that checked ok to toyota specs.thanks for all the help

TPS info

1. Loosen the two set screws that secure the TPS to the throttle housing. (DO NOT REMOVE THE SCREWS)
http://i132.photobucket.com/albums/q30/kbruington/tech/tps1.gif

2. Connect an Ohmmeter to terminals IDL and E2 of the TPS after removing the connector.
3. Insert a 0.70mm (0.028in.) feeler gauge between the throttle stop screw and stop lever.
http://i132.photobucket.com/albums/q30/kbruington/tech/tps2.gif

4. Rotate the TPS counter-clockwise and slowly back clockwise until the Ohmmeter just looses continuity, (infinite ohms).
http://i132.photobucket.com/albums/q30/kbruington/tech/tps3.gif

5. Secure the TPS with the two set screws.
6. Remove the feeler gauge and recheck TPS setting.
7. There should be continuity with a 0.57mm (0.022in.) feeler gauge inserted in the stop. There should be NO continuity with a 0.85mm (0.034in.) feeler gauge inserted in the stop.
8. Remove the Ohmmeter and reconnect the TPS connector.

http://i132.photobucket.com/albums/q30/kbruington/tech/41754251.gif

http://i132.photobucket.com/albums/q30/kbruington/tech/41754414.gif


I really do not like Haynes manuals either. But, if they show something for code 51, they are one up on AlldataPro. I spent a good 20 minutes fishing around, and there is nothing on it. The only reference I could find was "All detected diagnostic codes, except 51 and 53, will be retained in memory be the ECU from the time of detection until cancelled out."

Okay, looking around on the internet, I found a few things to start with, related to Code 51.

51 Switch Signal Diagnosis

* No "IDL" signal, "NSW" signal or "A/C" signal to ECU, during diagnosis check.

Trouble Area

* A/C switch circuit
* A/C switch
* A/C amplifier
* Throttle position sensor circuit
* Throttle position sensor
* ECU


I will gather the TPS circuit flow chart tomorrow. It is broken into several different pieces making it hard to post here.

Good job kris!

hey kris thanks for all this help/info i am going to try the tps settings you sent tommorrow they are different then what haynes shows.the code 51 what you listed is exactly what the haynes says.i check the complete ac system works fine and the tps i will find out asap the ecm thats why i was asking for the ecm schematic.thats all the haynes said then had no further troubleshoot/diagnostics on the 51.so i will check the tps first thing with your specs.and if thats not it i will check the ecm signals from that schematic you sent and let you know.hey thank you again for all the info.

well i set the tps according to your settings and were it uses the feeler guage at 0.034in should have no continuity it does so i got a new tps does the same thing.and is still running bad another friend that works on toyotas told me to unplug the tps after starting should run perfect if tps is a problem so i tried that still no change tested tps wires for correct voltage from ecm that checked ok.so i am back to the code 51 it still has not stayed cleared and has not ran any better.any other ideas i really appreciate all the help

Toycam, I don't know if this info I have is any good to you or not?
I have a 3.0L V6, 1994 and I know you have a 22re but I had alot of problems that your describing and it turned out that a sensor at the rear of the enigine, next to the firewall, was damaged when I had the head gasket replaced and it took it a few years to act up bad enough for my 4Runner to be undriveable, but I thought I would mention this to you. I had no ride for almost 6 months but as I said I have a V6 not a 4 cylinder but Your situation sounded so similair to mine I just thought I Post this.
Also Toyota and no one else could fix it until I found this One Older Gentleman that was handy with Toyotas. And he Got Me back on the Road :)

Good Luck Bud.
OzzyO :smokin:

hey thanks for the input i wish i had the sensor on the back then i would have something to test but the 4cyl dont have those sensors.i am hoping the old toyota master comes along and shoots a idea for me.any info or ideas is greatly apreciated thanks

Also check the neutral start switch/circuit. Check wiring for TPS circuit, A/C amplifier circuit, A/C switch circuit for bad grounds, shorts, and bad connectors at sensors. Also check the ignition coil. Even if the coil tests good, see if you can find a good one to test.

But wouldn't it have the same type of Sensor, BUT in a different location ?

OzzyO :smokin:

hey kris i would like your opinion on what i came up with since you were the 1 to help with diagnoses diagrahms(thanks) so i tested the ecm outputs with this schematic on the Vs-e2 ignition on plate closed i got 1.4v should be 3.7-4.3 then measuring fully open voltage stayed 1.4v should be 0.2-0.5 and when idling i got 7v should be 2.3-2.8v then i traced electrical circut wich is the mass air flow sensor so ohm tested was in specs tried another good same popping.so i unpluged ecm performed MAF test again from ecm plugs everything tested in range so that tells me the MAF/wires going 2 it are good.in your opinion would you condem the ecm at this point or is there a physical way to test ecm itself.if it was not espensive i would do it but it is a customers truck so they pay and dont want it not to fix problem if there is a way of 4sure verifying ECM is bad.please let me know what/were you would go at this point if it was you.thanks SS

just want to say thanks for all the help and info i got from everyone.i found that whoever did the timing chain on this engine had the cam timing off by 3 teeth.wich was causing the problem.thought i would say thanks and let you know what i found.

Thanks for the feedback