Innervision

I just checked the timing on my 94 4runner (v6 3.0 auto) because my mileage was only about 11mpg. At first I could not find the timing mark and then almost gave up. Then I noticed the mark was way advanced. It was out of the range of the timing indicator. I would estimate the engine was advanced to about 20 to 25 degrees BTDC. I adjusted the timing back down to 10 BTDC and the RPMs are now down to 800 at idle. I was at 1100 with the advanced timing.

The engine runs/ran great at both timings. Could running the engine at such and advanced timing cause any damage? I have a CEL but its an EGR temp issue (code 71). Hopefully no new codes will appear on the drive home.

Flash319

Did you have the jumper in? Is your TPS adjusted right?

turborich

Yeah, check your TPS. It through my timing 25 degrees outta whack. A simple adjustment solved it. May not be your problem but worth mentioning.

Innervision

I did have the jumper in. I will have to check the TPS.

The drive home was SLOW. After setting the timing to 10* my truck had no guts. I had the pedal to the floor going up hill and could not go past 45 mph. I set it back to 20* and now it runs great and has great acceleration and acceptable power going up hill, for a 3.0.

Its a donor engine from a swap I did back in January. So I am not certain of its history. I guess I can live with it at 20* BTDC. Unless someone can give me reason I shouldn't? I may pull the timing cover and see if the cams are off of TDC. Would this cause the timing to appear advanced even though its not?

abecedarian

Everything is probably fine with your engine / timing, just the TPS not adjusted optimally. Unfortunately, you cannot verify timing without the TPS working properly.

If the TPS isn't signalling idle / throttle closed to the ECU, the engine may have subtle driveability issues such as a hunting idle speed (fluctuates), timing not being able to be accurately set, less than optimal fuel economy, O2 sensor being used for feedback when it shouldn't....

You might try marking the TPS position, then putting the jumper in and rotating the TPS and see if you find a spot where the idle speed makes a sudden change and the timing drops to where it's supposed to be. If you find that spot and set the TPS right where the idle changes and timing goes to base, that should be where it needs to be. If you can't find that spot, the TPS may be faulty.
Or you can try the procedure here: http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml

xzyragon

ur distributor is off a tooth?

would be my best guess