1993 V6 Camry Stalls, drinks gas

[toy4runr]

The car is a '93 V6 camry with 175K miles.

It runs fine when it's cold, start it up and it runs like nothing is wrong with it, but as soon as it starts to warm up it starts to stumble, miss and stall. It is sucking gas at an astonishing rate. When it warms up it starts smoking from the back of the engine and out of the tail pipe. The smoke is blue and black. There is a STRONG fuel odor too that is only detectable when it start to blow smoke.

I changed the IAC with a used one from a salvage yard. I checked the plugs, they are black with carbon but otherwise new and good condition. The air intake had no leaks or cracks. PCV valve, plug wires, dist cap and rotor are new.

Could this be the fuel filter? Would it make it do this? Could it be the temp sensor that controls the mixture? Where is that sensor on this engine? I appreciate you help.

[dorifuto.boi]

check oil level. is oil level low ? you might be burning engine oil.

[BMR]

Could be the Intake Air Temperature Sensor (IAT). It located in the MAF sensor; look down its throat and you'll see a little plastic covered thing protruding in. There's a pic of it on this site; scroll down, the pic is one up from the bottom.

Also some good tuning tips on that page, good for a few free HP.

Edit: GAH!!! I misread your post, thought you were talking about air temperature, not engine temp. Disregard my suggestion.

[fenixus]

also the ECT (for EFI) sensor could be misreporting at warm coolant temperature and so getting the ECU fooled into adjusting the mixture hella rich when it's no longer cold.

check the resistance between terminals of ECT for EFI sensor both when it's dead cold and after car has been warmed up fully (shut it down before unplugging ECT).

[carsrus]

It is not low oil level and not fuel filter.

More then likely your ignition coil is going bad. Its a common thing that when it warms up they just die out. If your chugging an amount of black smoke that crazy you have a failure of a critical ignition component, aka ignition coil/distributor problem. Since cap and rotor are new that means its the coil. Common issue on older vehicles.

Just pull a whole distributor at salvage yard. Re-man distributors are pretty expensive. I think 93 uses a distributor, if it uses a coil pack then change it before your throw any money/time into this problem.

[Stillrunning]

Originally Posted by toy4runr

It is sucking gas at an astonishing rate.

Originally Posted by fenixus

also the ECT (for EFI) sensor could be misreporting at warm coolant temperature and so getting the ECU fooled into adjusting the mixture hella rich when it's no longer cold.

check the resistance between terminals of ECT for EFI sensor both when it's dead cold and after car has been warmed up fully (shut it down before unplugging ECT).

Originally Posted by carsrus

More then likely your ignition coil is going bad. Just pull a whole distributor at salvage yard.

Simple resistance test of ECT as fenixus suggests could save you unnecessary trip to wrecker and distributor exchange.

[BMR]

Originally Posted by carsrus

It is not low oil level and not fuel filter.

More then likely your ignition coil is going bad. Its a common thing that when it warms up they just die out. If your chugging an amount of black smoke that crazy you have a failure of a critical ignition component, aka ignition coil/distributor problem. Since cap and rotor are new that means its the coil. Common issue on older vehicles.

Just pull a whole distributor at salvage yard. Re-man distributors are pretty expensive. I think 93 uses a distributor, if it uses a coil pack then change it before your throw any money/time into this problem.

Good suggestion. But the ignition coil on this V6 (3VZ-FE) isn't inside the disty. It's mounted on the driver's side strut tower, right behind the air filter housing.

[toy4runr]

Thank you all so very much for your thoughtful and insightful replies. I fixed the car, here is what I did;

I replaced the IAC with a cleaned used part, new plugs, wires, dist cap & rotor button, replaced the ECT with a used one. At this point I realized that the number four cylinder was dead, so I took a long screwdriver and placed the blade of the screwdriver against the body of the front three injectors starting with number two. Number two and six were firing, but number the four injector was dead. I replaced it with one form a salvage yard and the car is running like a Toyota again! Thanks again for you help!

[toy4runr]

Well, the car is not fixed after all.

I changed out the IAC, PCV, and ECT along with the #4 fuel injector and the car started running normally so I declared it fixed.

Problem is that when it gets up to normal operating temps it goes right back to drinking gas and stumbling like it was doing to begin with. When this happens unplugging the ECT temp sensor causes the check engine light to come on, but the engine runs normally with the sensor unplugged. So I replaced the ECT with a new one from Auto Zone. The problem persists.

Could this be the Air Intake Temp sensor? How can I test this? I am having real trouble finding '93 V6 Camrys in the local salvage yards too. Anyhow, if you could point me in some direction here I would sure appreciate it.

[fenixus]

yeah, by all means test the IAT, you can do this on car, first test it at cold (measure resistance between terminals), then let the car fully warm up, unplug it and test again (you may need to shut it down right before testing).

I think the resistance-temperature correlation is exactly same as for the ECT.

also, unplugging the ECT on running car throws the ECU into a limp mode where the car starts running off the predefined fuel maps and ignores most sensors input. you have a bad misbehaving sensor somewhere, probably one of primary feeds, but I wouldn't rule out the oxygen/AFR sensors as of yet. Once fully warmed up car will switch to a close loop (can actually do that much earlier than that) and start relying on sensors entirely.

[toy4runr]

Yeah, another thing we just noticed with this cold front moving through. On cold mornings he has to plug in the ECT sensor for the car to run when it's cold, but as soon as it warms up he has to unplug the ECT or it starts running crappy and drinking gas again.

[Stillrunning]

At least on the 1995 the V6 has the intake air temp sensor incorporated into the MAF. There are two pins dedicated to it - THA & E2. Looking into the connector on the MAF they are 2nd pin from left and 3rd from left of 5 pin connector. It is tested with an OHM meter.

[toy4runr]

OK, it looks like the ECT sensor is working properly. I figured it was since it was new.

Right now it is cold in the mornings and the car does not want to idle in the cold or really run at all when it's cold with the ECT unplugged. So we can plug in the ECT when it's cold and it will idle up and run fine until it warms up to normal operating temps and then it goes to drinking fuel, smoking grey/black smoke, and won't stay running at an idle until we unplug the ECT sensor, then it goes into limp mode and runs fine. What other sensor could cause it to run so poorly and get such terrible mileage when it warms up? Any help is tremendously appreciated. I don't have the factory service manual and am really in the dark here.

[carsrus]

Change the coil......... There is no one sensor that will go bad and cause the car to chug black smoke. Its a physical ignition problem.

[toy4runr]

Coil? Dang, this is gonna be hard to source. The closest one of these in a salvage yard is an hour away. Alright then, I will see about getting out there to source the coil, ignitor, MAF, and anything else you can recommend? Is there anything else I should grab while I'm out there??