Crappy86yota

This is my first thread and I was woundering if you would have any knowlage on reading codes with the obd computer. the truck is an 86 22re I’ve been doing my home work and can’t find any good sources for checking these codes. I have a slight miss when motor is over 2000rpm nothing major just would like to know

recently did a head gasket

Jimkola

The diagnostic codes Toyota had in the 1980's was pretty basic, a far cry from later OBD where you plugged in a scan tool to pull data.
The early version had you bridge two terminals with a jump wire to access codes, there was no scan tool. Then you'd count the number of times the MIL (check engine light) flashed.
The rudimentary codes would typically give you the system that was malfunctioning, and that was about it.

Crappy86yota

but what connections in the plugs do I jump in just worried about shorting something out

scope103

Start here: https://www.4crawler.com/4x4/CheapTr....shtml#Reading

Jimkola

Yotatech thread

Jimkola

1) what sparkplugs did you use?
2) when you set base timing did the adjusting bolt land fairly well centered in the slot, or is it off to the side?
3 Did you adjust the TPS? if you did, is if fairly centered in the adjusting slot?

Crappy86yota

I don’t remember exactly what plugs and wires I chose to go with but switched to ngk wires and ngk copper plugs then retarded the timing a little. The truck runs a lot better but I still get codes 5 and 12 I don’t have an o2 sensor “previous owner installed aftermarket header with no port for an o2 sensor”. For code 12 I’ve got no idea

Jimkola

I assume the "miss" is since the headgasket replacement.
What about the distributer and TPS? Where are they sitting in the slot?

Crappy86yota

The cap and “button” looked to be in decent shape I have not touched the throttle position sensor. Although I have noticed that they are a common thing to replace. The plan is to stick to all oe Toyota sensors if I go the rout of replacing it

Jimkola

I think fewer TPS's would get replaced if people tried the timing light method to adjust. But just my .02
But if the distributer lock bolt is sitting off to one side in the adjusting slot my guess is that needs to be addressed first. If it's somewhat in the center than it's not an issue.

Crappy86yota

I set the timing by ear and throttle response at different rpm I don’t own a timing light yet one is in the mail

Jimkola

If you look at the sticky section in this forum you'll see my post on how to set TPS with a timing light. It also gives instructions on basic timing.
Where the distributer is sitting would make me nervous. Hopefully after you set timing with an actual timing light it'll be more centered.