3VZ-FE bogging when cold.. o2 sensor or otherwise?

[xjfish]

93 Camry Auto w 315K. I've been living with this problem for a while now, would like to get around fixing..

Starts easy, idles perfect cold and warm, drives very well after engine is warm
- Bogs/misses and feels like its going to die after taking off above about ~2,000 rpms or so from every startup where the car is not already warm. Runs fine after this initial "bogging down" for maybe 15-20 seconds of holding the gas pedal to the floor and going almost nowhere. Really picks up strong and fast after the car snaps out of this "initial cold bog down" Fuel mileage isn't as good as it should be.

Constant CEL. Throws a code for main Oxygen sensor. Would a bad 02 cause an extremely rich or lean condition for just a short time? Little to no improvement after unplugging front O2 sensor. I plan on replacing the o2 sensor(s) here eventually (OEM is expensive!) but I'm unsure if this is my problem.

Other suspects are a EGR valve and Engine coolant temp sensor. Does the computer use a different CTS than the temp guage? Could a "bad" egr valve cause something like this?

New plugs, fuel injectors cleaned.

Anyone had a similar experience? Thoughts and opinions appreciated

[BlueFusion6851]

I have only experienced this ONCE... and it was after a particularly cold Minnesota Winter's night. I would highly suspect the O2 sensor though, and while you are at it, clean your throttle body... run seafoam through your vacuum line... clean your EGR valve (see if you have black deposits inside of it)

I'd try the oxygen sensor first though. Check the wiring and connections and see if there is any missing wires.

[rawbi01]

I am having the same issue, please let me know what you find out!!

[BMR]

Mine has been doing this for quite a while. It starts and idles fine under all conditions. The motor just falls on its face when I step on the go pedal until it's warmed up for a minute or so. Just a minor annoyance, really.

My CEL is not on. I suspect the engine coolant temp sensor, or perhaps there's a problem with the fuel enrichening on cold starts. I'm curious to hear your findings, please post up if/when you get to the bottom of it.

[Eye8Pussies]

the egr won't make the car do that

change the o2 sensor first, and also check the coolant temp sensor

[Luckynumber5]

I have been trying to figure out what causes the well known cold engine bog down that almost all 3vzs have.

I know it is caused by an extremely lean condition when the bog occurs, almost no fuel is being delivered and I believe the cause is the air flow meter. After I got in and messed around with mine the problem stopped.

Another thing that will cause the bog that is easier to fix is the distributor cap and rotor, if the cap and rotor are old theres a good chance thats the problem over the air flow meter.

[Eye8Pussies]

if it's any help for diagnostic purposes..., just a reminder that the 3vz has an extra cold start injector as well that can go funny on you...

[Luckynumber5]

It only injects while cranking though, the problem occurs well after the cold start injector has closed up.

[BMR]

Originally Posted by Luckynumber5

I have been trying to figure out what causes the well known cold engine bog down that almost all 3vzs have.

For some reason, that's comforting to know.

Originally Posted by Luckynumber5

I know it is caused by an extremely lean condition when the bog occurs, almost no fuel is being delivered and I believe the cause is the air flow meter. After I got in and messed around with mine the problem stopped.

What, exactly, did you do to your AFM?

Originally Posted by Luckynumber5

Another thing that will cause the bog that is easier to fix is the distributor cap and rotor, if the cap and rotor are old theres a good chance thats the problem over the air flow meter.

Mine's been doing it for a very long time (like the last 100K miles), and I try to change out the cap and rotor every 60K or so, so I'm sure it's done the bogging with a new cap and rotor. BTW, I always use Toyota parts for that.

Question: Isn't there an incoming air temp sensor in the intake somewhere?... Maybe that's gone bad? But then again, if that was the problem, wouldn't it do it all the time???

[llcoolpass]

i have the exact same problem. im not sure i would phrase it as, ''glad," that you have the same problem as me. but im not alone.
i also suspected the air flow meter is binding up [old, plastic, archaic-technology ]
i have no codes and car runs well after incident, and no problems once warmed up. i have new 02 sensors. just to help you all see it's not cars with "other problems". i have a stick shift, is this bogging thing happening even with the automatic cars?

the event is more pronounced at slower speeds in second gear, but 1st too i think?? the slow speeds are like 10ish mph to 17ish mph acceleration [i cant check anymore, too hot outside]
[not talking reallllly slow speeds, that kind of thing is something different -- just to make myself clear to those people used to ppl not knowing what they're talking about lol]
-- if i'm reallllllly smooth and incremental [not using the clutch at this point to be clear to anyone suggesting clutch issues] i can avoid it, otherwise, gets bogged a bit.

i also suspected it was the idle air control somehow messing up things, one way or another.

by cold, i think it only happens below 40 degrees. though, i did not scientificaly record the info on this.

how long has mine been doing this... i dont know. i only have driven for 6 months now, i think it always did it. who knows what it was like new.

[Luckynumber5]

The air flow meter has an intake air temperature sensor built in. If you take the meter off and look in the inlet you will see a small plastic bit at the top, thats the sensor. If it's dirty try cleaning it with some electrical parts cleaner. May help...


The problem has me puzzled honestly, it went away after I adjusted the tension spring in the meter to run leaner, and messed with the idle air bypass.

You could always just let the car warm up for about 30 seconds before driving, that stopped my 3vz automatic from bogging.

[llcoolpass]

well letting it warm up *like that* is terrible for fuel economy. when its super cold , it would take far more than 30 seconds to appreciably warm it up anyway. so that's not a sol'n

you messed with the two things that i was thinking it was related to. interesting. it still didn't work, it just somewhat patched up the problem?

i wonder, has anyone replaced the airflow meter with a known good one, and seen the problem disappear?

[davemac2]

The colder the engine, then more rich the fuel mixture needs to be. So assuming this is a too lean condition is reasonable. For high mileage V6's, the air intake hose between the TB and filter/air meter develops cracks in its folds that can be very difficult to see unless you remove the hose for inspection and stretch, poke and pry the hose well while looking. This type of leak won't affect warm startup much at all. Also check the IAC hose, the PCV hose, the PCV valve grommet, since they are both attached to the larger intake hose, and the air filter plastic shell housing.

dave mc

[Luckynumber5]

I have an intake, so a leak is out of the question

30 seconds may not make the temp gauge move, but it's plenty of time for the ecu to switch into open loop mode.

Problem still happened with a new AFM, but if you can find one cheap try switching them. Our AFMs run backwards voltage so one form another car will not work, and these particular AFMs were only over here for 2 years.

[llcoolpass]

30 seconds IS NOT enough time for the ecu to sw to closed loop.

my intake tube is not cracked. i would know, have my take apart everything on top of my engine and am in the process of putting it all together