I found another pic of a 1988 pickup. You can see the diagnostic cover and where it is located relative to the fuse box in your pic and the finned part on the inside of the fender. Hope this helps. Looks like yours is missing.

 

I thought the same thing about the yellow connector but theres not nearly enough pins to match the normal check connector.

That pictures looks to be the closet to my setup; however, I checked my truck and its not there.

It may be a dumb question, but would the truck run if that connector has been cut out? And if it was originally carbureted, the harness wouldn't be there, correct? As its only for the EFI? Only reason I mention the carb is because of the dead ended hoses with what looks like two fuel filters connected?

 

Yeah, there would be no need for a diagnostic port for a carb'd setup, because there is no ECU to drive the fault logic and nothing to sense really.

Was that an option for the 88 models, and could you find the original engine spec from the VIN plate?

 

Post # 7 has a pic of his engine so it is EFI. Even if it is an EFI swap, The diagnostic port is part of the EFI engine harness and should have been carried over with the swap. It may have been cut, if so, the "easiest" way to pull the code is to remove the ecu and open it up. On the circuit board near the harness connector plugs you will see that each terminal is labeled. Find the terminal label " T " or " Te" and then find the corresponding wire the goes to that terminal. Splice in a long lead to the wire and when you ground it the ECU will flash the code.

 

Can I also do this to properly set the the timing?

 

Yep!
Also, you could permanently ground the lead and install and switch/button inline. Then you could activate the diagnostics at the flip of the switch at any time.

 

Damn good idea! I never would have thought of that. I'll be doing that this weekend. Thank you!

 

No problem. Just in case Toyota stopped silkscreen labels on your year truck, here is a pinout diagram of the ecu.


Ground the terminal labeled "T".

 

Does it have chain rattle on startup or under load? Just curious...

 

No chain rattle. It has a valve tick, but what 22re doesn't??

I was able to check the code which was code #12, Engine speed (rpm) sensor circuit. I set the timing the proper way and it drove a little bit better but not much. I started pulling spark plug wires to see what would happen. If I pulled #1 or 4, the engine shut off. If I pulled #2 or 3, nothing happen. My brother got shocked on cylinder 3. That's as far as we got before the rain came. What do yal think?