'89 22RE Ignition Timing

If you short test and E 1 and the timing doesn't change it is often because the TPS is set incorrectly. It has to tell the computer it is at idle before it will set timing back to base idle. so loosen screws on TPS (throttle position sensor till it shows probable 0.5 volts or so, or just turn it a little in the right direction and tighten it then short connector and see if timing changes (you can usually hear the difference in engine speed.

Thanks edmechanic, I get about 1 volt VTA to GND so it is too high. Also the IDL contact may not be closing. With the voltmeter between IDL and GND I get over 5 volts. When I do this it definitely retards the engine and the timing was a few degrees ATDC. I need to find a special offset philips to loosen the lower screw on the TPS.

Update.. I remember having fiddled with the throttle plate adjusting screw to set idle a long time ago. I left the TPS alone and turned this adusting screw back until the IDL to GND contact closed. This retarded the timing and RPM. I reset RPM with the correct idle adjustment screw. Shorting Test and E1 brought the ignition to base timing as expected and I was able to set the 5 deg BTDC as required. Runs great now. Thanks again edmechanic, you pointed me in the right direction.

You know how I found out this little bit of information. Well I have a 89 Toy truck, 2.4L and couldn't set it because I was doing a pre smog tune up. I worked part time at a part time auto shop. So I figured my distributor was off so I played around with that. That didn't work so I spent 150 for a timing gear set and changed the chain. Well that didn't help and I finally read about the TPS on a web site. Boy I felt stupid, but I learned about that and it works for all old toyotas, so pass it along before they waste 2 days changing the chain.