I took my 93 4Runner to smog check and failed first time. Tech informed me my timing was set 20 degress off???????????? After adjusting timing, it seemed wierd because I had to turn the distributor to the extreme of allowable travel to set timing accordingly. Anyway, passed smog test. From then on, this truck ran terribly. Died after cold start, no power, idle variation, etc... When I set the timing back to the center of allowable ditributor adjustment travel, I cant see the timing mark, but the truck runs great! I am stumped! Any input would be greatly appreciated.

1993, V6, 4WD

 

I had the same problem you are describing. It turned out to be a bad TPS (throttle position sensor). You can test your tps with a multimeter to see if it's bad. It may just need to be adjusted. Use the search button to find more info on your tps.

Pull your #1 spark plug, stick your finger in the hole that was occupied by the plug, have your buddy crank the engine with a wrench, when you feel a blast of air go past your finger have him stop. The timing mark on the engine pulley should be at TDC and your rotor should be pointing exactly at your #1 spark plug contact on your distributor. If this is the case, your timing is fine and you are looking at an electrical problem (like your tps). If this is not the case, pull your distributor and line the rotor up with #1. Put the dist back in with enough allowable adjustment space to bring er back to 10-12* btdc.

 

Thanks for the input. I'll check it out and get back with results.

 

Okay, I have tested the TBS. Results are

Test #1. k ohms within range
Test #2. Nothing- Open Circuit
Test #3. Nothing- Open Cicuit
Test #4. k ohms within range
Test #5. k ohms within range

Specs are:
Test Clearance between
lever and stop screw Between terminals Resistance /'89-'95 (ohms)
1. 0.00mm (0.000") VTA - E2 200-800
2. 0.50mm (0.020") IDL - E2 < 2.3K
3. 0.77mm (0.030") IDL - E2 Open / Infinite
4. Wide Open Throttle VTA - E2 3.3K-10K
5. n / a Vcc - E2 4.0K - 9.0K