2zz idle surge issue

One thing to note:  The coolant fill bottle will de-aerate and trap any remaining bubbles with the cap on.  No need to, and no advantage to driving around with the cap off.  If there was any air, the coolant bottle level will drop.

Even if there is no CEL lit, it is worth hooking up an OBD2 reader to check for codes.  

Dave

I've been clearing the OBD2 codes and fuel trims every time I change something.

I have misfire codes that I guess are from the engine surging. 

@lyzekachen

You need to write the codes down each time before clearing.  Then once you have a few sets, research the consistent codes and start troubleshooting from there.  Random codes may not be random...

So the codes when I initially got the car and idle surge issue were

P0441 evap

P0446 evap

P0171 bank 1 lean 

To address P0441 and P0446 I replaced the evap canister/vsv on the canister I did a smoke test to find evap leaks and replaced two breather hoses and the gas cap. 

To address the P0171 I also sent 4 yellow injectors to RC fuel injection to get injectors cleaned. one injector started with 171cc and came back with 309cc the rest were in the range of 270cc and came back 310cc.

In order to attempt to make the car legal I've had to install the following 

Weapon r intake 

01 celica gts throttle body 

01 celica gts intake manifold

01 celica gts header

midship garage midpipe

ebay exhaust

new o2 pre and post cat o2 sensors

new maf sensor

During my diagnostics, I've been consistently getting I haven't been running the car long enough for any other codes to set. I haven't been too keen on driving the car around with the idle surge. 

P0100 maf

P0505 iacv

P0120 tps

P0300 random misfire

P0301 Cylinder 1 misfire

P0303 Cylinder 3 misfire

I assume the above codes are from me unplugging the various sensors and starting the car. 

I've also replaced the coil packs and spark plugs. When I took the out all the spark plugs they looked pretty consistent across the board so I can more confidently say all 4 cylinders were performing similarly. They weren't excessively sooty (rich) or white (lean).

I've also been basing a lot of my diagnostics on this thread 

https://www.spyderchat.com/threads/idle-surge-in-2zz-without-pfc.66898/

Did the car come with a swap harness or did someone wire it up using the pin out diagram?

I believe the previous owner used the wiring diagram following the below thread.

https://www.spyderchat.com/threads/2zz-swap-wiring-spreadsheet.154361/

I have not checked his wiring work though during the sale he mentioned the wiring work was not as hard as I made it out to be. 

I did check his TPS wire and he did switch the polarity on that. 

Posted by: @lyzekachen

I believe the previous owner used the wiring diagram following the below thread.

 

https://www.spyderchat.com/threads/2zz-swap-wiring-spreadsheet.154361/

 

I have not checked his wiring work though during the sale he mentioned the wiring work was not as hard as I made it out to be. 

I did check his TPS wire and he did switch the polarity on that. 

I have read plenty of situations for exactly the same issues you are going though because of the pin out was incorrectly done.  No one knows why and some were eventually corrected with little feedback afterwards  because the original poster would vanish.  One guy inherited a failed 2ZZ swap project where the wires were taped together.  The reason why I asked because its a very typical scenario of someone inheriting a budgeted 2ZZ swap where they were trying to save money on the swap harness. 

 This is not to say there weren't any successful pin out swaps but there are a good handful of incorrect ones done.   Usually they go unnoticed because the  original owner of the swap used a PFC and all of the problems come to  next owner tying  to revert back to a factory ECU to get it though inspection. 

Based on your last codes, I would go through the trouble shooting procedures (just need a Volt-Ohm meter) in the Celica shop manual for the TPS and IAC, and MAF codes.  This will probably uncover a wiring error.  

A wiring issue would probably be my worst fear. It would also be beyond my ability to check. I will try and check for mechanical issues and save the wiring/electrical issues for the professionals. 

This is a picture of the throttle body in the car right now

Though I found this picture at http://maxbore.com/toyota.html

My guess now is either a combination of failed/failing iacv and leaking throttle plate or just the leaking throttle plate. 

Check the TPS connector. Make sure it is clean and the connection is secure. 

It's been a while but I finally have an almost successful update on the car. 

The misfires and evap codes have been cleared. I send the injectors in for cleaning and replaced the EVAP canister, Fuel pump, filter, mesh, check valve, and gaskets. 

I've also replaced the iacv and tried 3 different used TPS sensors and checked/cleaned the connection on TPS.

A dirty or poor connection on the TPS will cause the idle to surge like crazy at a non moving idle 

Cold start idles at 1900-2100 until hot, then drops to 1250 or 1450 depending on the car's mood. Idle never drops below 1250. 

Fuel Trims are pretty bad but not bad enough for CEL.

I've confirmed it's a bad TB. I'm going to look for a used one. Once I find a used one I probably send the old one to maxbore to get it rebored. 

I confirmed it was the TB by sealing the butterfly plate with electrical tape while letting the iacv port stay unsealed. Idle settled at 900 once the car was hot.