Character, assuming your timing is at 20 btdc still.. you should take it down to 10-12 deg. The cold start injector, i'm not asking you to REMOVE the injector, just unplug it. It could be the case that the injector is leaking which will spray way to much fuel into the air stream and cause hesitation, loss of power etc. Or, there could be a short somewhere in the system which tells the ECU to activate the injector after you start it and so on.

 

I'm in Peoria on 83rd and deer valley. It is set at 10btdc but it will try and kill itself if I full throttle it.

 

Ya that's a hike for me. Ouch. Wish you were closer.

 

I'll try and unplug it to see what it does.

 

Yeah its pretty far and the 4runner isn't dtiveable. Thanks anyways.

 

It could be that the valve timing (not the distributor timing) is off by a tooth. This could have happened when the timing belt was changed. Nothing can compensate for an error like that, and the engine will run and idle like crap. A compression test should give you some information on that - if all cylinders are low you'd want to pull off the timing cover and check the cam timing.

Otherwise, it's likely a sensor that is giving the ECU bad data and causing it to adjust fuel/timing inappropriately for actual conditions. Most likely candidates are
- VAFM
- TPS

Both of these sensors have diagnostic procedures in the FSM using a multimeter. Check here:
http://personal.utulsa.edu/~nathan-b...92volumeai.pdf
and here
http://personal.utulsa.edu/~nathan-b...93throttle.pdf

 

okay update on the truck. i set it to factory timing and unplugged the cold start which had no change. then i unplugged the tps and the idle smoothed out but as soon as a full throttle it, you hear a loud knock from the engine and smoke would come out of the exhaust and it would die. im going to take a full day to check the timing myself.

 

pretty sure it was black smoke too

 

Black smoke means way to much fuel. I haven't read every post, have you checked the fuel pressure, and fuel pressure regulator?

 

Fuel pressure is fine and the regulator makes a loud ticking noice but there is no gas coming out if its vacuum port.

 

The ECU needs proper signals from the TPS and the VAFM to get the fuel mixture right. I hope you can run those tests when you get time to work on it.

 

Timing isn't off, the cam marks were all lined up so that's out of the question.

 

Could low compression cause this?

 

Possibly. A compression test is pretty easy to run - you just have to pull the plugs - and will tell you a lot about the mechanical health of the engine.

But, given that the idle smoothed out when you unplugged the TPS, I'm guessing the TPS and/or the VAFM are sending bogus signals to the ECU. Check those out before you dig much deeper. 20 minutes with a multimeter and the FSM will tell you a lot.

 

I'm checking that tomorrow. Setting it to 20btdc it will run fine for a few minutes then crap out and then you can then the engine off and back on and it will be good again so I don't think it could compression could reset itself.

 

Just a guess here but bad coil getting hot and quitting cools down then works a little longer .

This along with something else.

 

I thought that too but when its a 10btdc it will barely run. It won't run good in the beginning like it does at 20btdc.

 

Can you post up a video showing start up, and when the symptoms kick in. Maybe some shots of the tach while you experience the problem.

I read that you said you could barely get the dizzy to go down to 10°BTDC? Did you check to see if its off a tooth or two? I have accidentally put mine in once at 180° out, and it would run, but had some oblivious timing issues.

 

While I had the timing cover off and the engine cranked to 0, I pulled the distributor cap off and checked the rotor and it was on cylinder 1 so its not off. I'll try and post a video of it running when I get it put back together.

 

Hey guys its been a while since I posted on here because I was trying everything on my truck. I just ran a compression test and all cylinders are good so now I know for sure its a sensor or even my ecu is bad. The problem has gotten worse now to where it won't hold an idle, it misfires like crazy, sometimes when I start it, it will die when I press the gas. And now its almost impossible to get it over 30mph. So now I'm checking my tps, cat and coil.