12-31-2009, 10:26 AM
One with the force
Join Date: Jul 2007
Location: North America
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- Do a seafoam treatment before cleaning the throttle body to clean the intake. Good time to clean the EGR passages too. If you are changing plugs and/or O2 sensor, do it after running the Seafoam treatment. See this thread: http://www.toyotanation.com/forum/sh...70#post2946870
- Take the throttle body off to clean it.
- Only use a cleaner made for throttle bodies. And a toothbrush. And clean t-shirt rags. Be sure to get both sides of the throttle plate/butterfly valve.
- If you soak your throttle position sensor (TPS) in any kind of solvent you'll be in the market for a new one. Probably would ruin your dashpot filter too. So don't soak it.
- Soaking could also destroy the rubber seals of the AAV/IAC - the cold idle-up valve. Okay to give a few shots of cleaner in the cold idle bypass passage (lower hole in front of butterfly valve), but invert it after to let the solvent run out. Hit the hot idle bypass (upper hole) with several good shots of cleaner too.
- After it's completely dry, put a drop of light oil like 3-in-One at each end of the throttle plate shaft and work it in.
- Check that the IDL and E2 contacts of the TPS have continuity when throttle is closed and do not have continuity when throttle is open - see the ENGINE - MFI SYSTEM - THROTTLE BODY section of the factory service manual (fsm). If they don't have continuity when closed, try adjusting position of the sensor per the fsm. If you can't get them to make contact, you need a new TPS. Check that resistance between VTA and E2 is in range with throttle in all positions, and verify that resistance smoothly increases and decreases as throttle is slowly opened and closed, with no spikes or dropouts (otherwise you need a new sensor).
- Use a new gasket when you remount the throttle body - the one from toyota is worlds better than the Fel-Pro you'll get from a parts store.
- Use the correct torque amount in the fsm - it's not much. Don't overtorque. If you don't have a torque wrench, you can try this technique when you first remove the throttle body: crack the mounting nuts in the remove direction to free them, then re-tighten to just a bit past their original position to get a feel for the right torque. The technique is iffy because the nuts may not have been torqued correctly when last mounted.
- Check operation of dashpot (& throttle opener if a 92-95 truck) - instructions in the fsm.
- Never adjust the throttle stop screw from its factory position.
- Make sure the air hose has no cracks or leaks.
- Reset idle to spec (22RE - 750 rpm; 3VZE - 800 rpm) by adjusting hot idle screw after engine has reached operating temperature. It's okay to make the speed a bit higher, up to 900 rpm max if the motor runs more smoothly at a different setting. (But when setting timing the speed needs to be at spec.)
89 4x4 X-Cab V6
WARNING: I'm not a professional tech - use any advice at your own risk. Working on vehicles is risky: you can kill or maim yourself or damage your truck if you don't know what you are doing. It's your responsibility to get qualified help if you lack auto repair training/experience.
Last edited by sb5walker; 12-31-2009 at 07:01 PM.