Toyota Repair: Camry stall - Part 2, coolant temp, pvc valves

Question
During warm up, the engine has micro shudders and you could hear the rhythm of the engine erratic.  It's minute, and I detected it when you put your hands and ears near the engine.  You wont notice this if you're standing 5 feet away.

Took samples of fuel and shook the fuel filter, its clean.

There's engine light when cranking and during stalls, but could the EFI relay be the problem or acting crazy?

Noticed that the plugs used are the Denso PK20R11 (which is recommended for Japan specs).  Is this correct?

Btw, I have not changed the 02 sensor.  I do not get ECU code even if I disconnect the sensor and rev above 2500rpm.  I have heard from friends, that Toyota has problems with 02 wiring harness in some parts of the world.

Please help.

==============================================
1st Query
=========

I have 1996 camry 2.2 5S-FE engine.  It stalls after 3-4 minutes of cold starts.  restarts after waiting 1 minute.  Works fine then.

I have changed IAC, thermostat, plugs and wires, Intake temp sensor, coolant temp sensor, TB cleaned and all cooling fan relays in engine area.  Mech check fuel system, the pvc valves and distributor - everything ok.  No diagnotic errors except when too much heavy cranking, i get code 13.

please help!!!!

Answer
Ive seen a few things that lead to extended crank, and stall.
The EFI main relay- If thats the case youll have no check engine light on the dash when it doesnt start. Thats because there is no voltage to the ECU.

I also have seen a bad pickup in the distibutor. They usually cut out when hot, but have seen them cut out as you described on occasion. No way to really check. They test fine, you need to swap one to check it.

Ive seen a bad O2 sensor do that also, but usually get a code in the ECU for it.

Also dont look past something in the fuel.
Take a fuel sample.see if its got water or dirt etc in it.

Let me know how you make out.

Mike  

Answer
plugs are ok
Ive seen heavy carbon deposits in the engine do as you described also, When cold they soak up the fuel and it runs rough and lean. When they are saturated, 2-3 min it runs better.Actualy will run rich as fuel drops drip from the carbon.
If you had a bad relay youd have no light so that sounds ok.
If you had a bad wire you will get a code, either a short or an open, so I dont think thats it.

I have seen engine temp sensors do this also and NOT store a code because they are just inaccurate not shorted.

Mike

Mike