95 Camry LE AT stall when hot but normal when cold

[ben_95_CamryLE_4Cyl]

I have 95 Camry LE 4 Cyl with automatic transmission and 204k miles.

When I run camry in the morning, it runs normal for about 30 minutes. After 30 minutes, when temperature gauge is at middle, car runs normal in all gears. However, at stop light car hesitates when car has run for 30 min and finally car shuts down. When I restart hot car, check engine light shows and engine kicks but does not start at all. I wait for 4 hours and let it "cool down" and car starts and runs normal. When car is cold all gear works normal. No gear shifting issue or noise. When hot, no gear noise but car become hesitant to start at stop light and stops all together with check engine light.

This car was not used for about 3 months but ran fine. This camry has many replaced parts (new PCV valve, cleaned throttle body, new distributor cap+spark plugs+distrib cables, newer timing belt+oil pump, new radiator, fuel pump, barke, battery). Most parts changes in last year or so and no pproblem until now. Transmission oil level is normal when car running in park on level ground and transmission oil looks norma (no burnt smell and pinkish)

Is it transmission issue or engine/engine control issue?
How do I diagnose the problem and fix it?

Thanks in advance for your help. I am newbie but enthusiastic and will try suggestions.

Thanks,
Ben

[73sport]

Sounds like step one may be to grab the data the ECU is suggested regarding the CEL. Roll into your favorite auto store and have them pull the code. Depending on the production date of your car it may/may not provide additional information. That is, the 96 models were OBDII compliant and offer more data like what the basic conditions were when the CEL was triggered (freeze frame data).

Beyond that there are two lines of thought; its either not getting fuel or not getting spark after it warms up (or spark at the wrong time).

Do you know why the fuel pump was replaced?
I'd hazard to guess you'll be looking for an ignition related failure as it heats up.

Is that the original gas from when it was sitting?

[Mike Gerber]

"Is that the original gas from when it was sitting?"

^ 73Sport asks a good question. Is that the original gas?

Also, when you cleaned the throttle body did you spray the cleaner liberally in to the square or diamond shaped port in the base of the throttle body? That hole leads to the idle air control valve where your problem may exist.

Next thing to check would be the coil inside the distributor. Weak coils cause problems when they heat up. Remove the coil from the distributor and check it with a digital volt/ohmerter for being in spec. If you don't have a manual to determine what the normal range of the coil is, you can download a Toyota factory service manual for free at the top of the Camry forum over at AutomotiveForums.com. Here's the link:

http://www.automotiveforums.com/vbul...d.php?t=497839

When the coil is out of the car, inspect it carefully for any cracks. Many times these coils get cracks in them and short themselves to ground on any metal inside the distributor. My guess is you have a bad coil.

If that all checks out I would use the DVM and the manual to check the engine coolant temperature sensor. It too may be out of range and telling the car's computer the car is cold when it is warm. This could give the car an excessively rich fuel mixture, essentialy flooding the engine.

Mike

[LittleWhiteBubble]

coolant temp sensor maybe?

[ben_95_CamryLE_4Cyl]

This is 95 camry so it does NOT have OBD II. I will ask Autozone gy, if they can read diag code on this 95 camry.

I had fuel line leak and car was hesitant too. While changing a fuel line section and it had original 15 year old fuel filter so I changed fuel filter as well.

Car has 3 month old gas and I had poured some injector cleaner 3 months ago. I am trying to burn off old gas but it still has a quarter tank of old gas. I am trying to run the car but with car stopping at hot , I am not able to use car much.

I have tested ignition coil and ohm resistance looked in normal temp range.
Primary resistance in 0.4-0.6 ohm range and sec resistance 9.6kohm - 14.4 kohm range.


I wonder if my transmission is getting hot. I have seen some smoke in the back of engine compartment but I thought there is some old engine oil leaks. Engine has some old oil drips and it smokes after 3 month sitting home.

I think it smell like engine oil but I could be wrong.

Fuel filer area has no fuel leaks for sure. I check everytime I open hood for gas leaks.
There is no gas smell either.

Thanks for your help.

Ben

[ben_95_CamryLE_4Cyl]

Thanks 73sport, Mike and LittleWhiteBubble for your reply.

I have sprayed carb cleaner in diamond hole in throttle body liberally and changed pcv valve too 6 months ago. When I looked at diamond hole area few days ago, it looks clean. No gummy dusty residues there.

I only checked primary coil resistance while ignition coil is in the distributor. I have not taken ignition coil out and examined for crack. May be I should have carefully examined it for cracks. Ignition coil is 15 year old.

Cooling temp sensor looked ok. It did start cooling electrical fan I noticed when hot.
I will try to check cooling temp sensor on bottom of the radiator.


Thanks,
Ben

[LittleWhiteBubble]

The switch on the bottom of the radiator only controls the fans. The temp sensor is near the intake. The one for the gauge and the one for the computer are next to each other.

[Mike Gerber]

The engine coolant temperature sensor is located to the right of the engine, as you are standing in front of the car, on a water port on the right side of the cylinder head. It is under a green plastic connector. That's the sensor that feeds information to the car's computer about engine temperature and helps control the proper fuel mixture. It is not associated with turning the cooling fans on and off. That is a separate sensor.

My money is still on a crack in the coil.

Mike

[73sport]

If the coil is at fault, you could A induce it with hair dryer while cold or B buy a can of Freeze It and Cool the coil after it stalls.

I would run the engine cold in the darkest of dark and look/listen for spark jump. It may not be visible, but also a light mist of water from a squirt bottle should not kill it either (on the coil and ignition wires).

Mike brings a feasible point, when cold it runs on the IAC. When warm it cuts over to the TB for air (IIRC). Perhaps something in the TB is plugged? Do you see any broken or dried out vacuum lines? Maybe the EGR is coming on Full Bore and killing it? But it should run at higher RPM just not idle.

So the question is, if you ran it at 2500 RPM (stationary, no driving) will it warm to temperature and continue running? Or does it only Not Idle when warm? Or does it only die when driving?

Testing the ignition when hot and "dead" can be as simple as pulling a plug wire and offereing a path to ground (like a spare spark plug) and cranking the key. Does it have a spark? If yes, and its purple to white in color, than its likely NOT the Ignition. You could also confirm this with some starter fluid into the intake. Does it run for 5 seconds on starter fluid (open TB valve and squirt into intake plenum).

After this test, we look for fuel issues.