sickcrewcab

I have a 2000 single cab tacoma. 2WD 2.4 liter 2RZFE Calif AT. I bought this truck about 3 weeks ago with a blown head gasket/cracked head. Decided to install a rebuilt engine since it has 216K on the odometer. I dropped the engine in and now I'm stumped with a high idle issue. Below is a list of things that I have checked and tried in order to fix the issue. When the engine is cold it starts and idles anywhere between 1200-1400 RPM. When the truck warms up it is idling around 2K RPM. I'm running out of ideas and any input is appreciated.

PCV Valve replaced (during engine install)
New Fuel Filter (during engine install)
New Water Pump (during engine install)
New Oil Pump (during engine install)

Checked IAC valve per FSM instructions. I was only able to get it to move one direction. Went to the junkyard and bought an entire new throttle body (because they wouldn't sell me just the IAC) new to me IAC valve functions correctly.

Checked routing of all vacuum lines and checked for vacuum leaks.

Sprayed carb clean around intake where it mates to the block and where the lower half of the intake bolts to the upper half. Saw no difference in idle.

With a scan tool I checked the Engine coolant temp sensor and it reads 185 degrees when warm.

Scan tool says engine load is running approx 20%.

TPS sensor resistance passed resistance test. Also have a second TPS sensor that was installed when I put on the new throttle body.

Throttle body butterfly closes all the way to the stop. I adjusted stop to fully close the butterfly which causes it to stick slightly when i stepped on the throttle. So put it back at original position. Butterfly does not have play from side to side.

Battery has been unplugged multiple times during engine installation and troubleshooting. The only engine codes I have seen have been induced by unplugging things in order to check function.

I've spent hours on here and searching google for a possible fix to no avail. If anybody has any input please let me know. Its making my brain hurt. Truck also has AC and power steering.

Thanks

enapa

When you have the battery disconnected how long is it disconnected? I would leave it disconnected for at least an hour. Also turn the headlights to the on position when battery is disconnected just to be 100% sure nothings left in the system lol. Also how much you drive after will make a difference. The ecu needs to relearn and it takes some mileage. Sometimes up to 20-30 miles. If none of that works i would lean towards a vacuum leak. Maybe one of the lines has a crack you cant visually see?

sickcrewcab

Thanks for your reply. The battery was disconnected long enough to clear the check engine lights I get from unplugging sensors while troubleshooting. The one time I didn't disconnect the battery I drove the truck long enough for it to clear its own CEL. I've put about 90 miles on this motor since I installed it. I've been over the vacuum lines so many times Ive lost count. I'm stumped on this one. I'm going to install a new intake manifold gasket set and see what happens even know I can't get it to idle up or down with carb cleaner.

During this last week I've tried a few things. I checked the VSV valve to make sure it was operating properly.

I've checked all ground wires with a meter to make sure they are good.

In trying to eliminate the fact it had anything to do with the IAC valve, I put a piece of exhaust tape over the IAC valve port in the front of the intake before the butterfly. (I know bad idea if it ever sucked it in, but I didn't drive it or throttle it) besides making the truck harder to start, it still idles high.

TPS sensor on the scan tool is reading 9.8%.

When the truck is cold it starts and idles about 1200 RPM, increasing to 1800-2000 RPM when its hot.

I'm at a loss for ideas from here.

enapa

Man im stumped.

trx125

Check all your grounds good. I chased a high idle and code 0420 for months. Cleaned, checked and rechecked everything. Finally found the ground wire from the battery was shot(inside the cable), ran new grounds for the battery, fuse block, body and chasis grounds. No more codes or high idles!

sickcrewcab

I still haven't been able to figure this out. Downloaded the FSM and checked all the voltages and resistances at the ECM. Replaced the intake manifold gasket. All grounds are good and verified with a meter. Vacuum lines are good and replaced. I'm out of ideas and decided I'm going to take it to the stealer in the morning and let them figure it out. I'll let you guys know what it is when I get it fixed. Thanks for the help.

enapa

Update?

Swede