2002 Stalls after starting, not able to accelerate

Your car probably will have logged DTC P3190 or P3191 (low engine power, engine no-start.)

In that case, clean the throttle plate and throttle body interior. Make sure you do not contaminate the mass air flow sensor during this process. If the MAF sensor is dirty, remove it and clean using MAF sensor spray.

 

Yes, you can just remove the sensor assembly with the two phillips screws. You should also have mass airflow sensor cleaner (no other kind of cleaner) on hand.

There is a little amber bulb you can clearly see sticking out, that looks like the MAF sensor, but it's really only the intake air temperature sensor, which is part of the same assembly. The real MAF sensor is a couple very fine wires that you can only see if you turn the assembly around in your hand until you can see deep into a small air passage running through it. Those are the wires you want to hit with the stream of MAF cleaner. Other than that, don't touch them with anything.

-Chap

 

I would drain the oil to midway between the marks on the dipstick. You can see my posts on here I have some very similar issues. I just cleaned the MAF and drained the oil after finding it had been filled slightly above the mark and I have had very positive results. Maybe coincidental. There are some solid contributors to this forum. Follow their suggestions.


iPhone ?

 

Start with the MAF cleaner spray which should cost <$10. There is no reason to replace the MAF sensor unless it has actually failed. Remove the two screws for MAF sensor removal.

While the sensor is out, inspect the rubber O-ring on the base of the stem that inserts into the air cleaner housing, which provides an air-tight seal to the housing. Make sure the O-ring is in good condition. If there is any damage then buy a new O-ring from your local Toyota dealer's parts counter. You do not need air to be leaking in around the sensor.

I would say it is not necessary to drain the engine oil at this time, if the level is at the top dimple on the dipstick. First try cleaning the MAF sensor and then see what happens.

I also would not be concerned about a slight pool of oil at the bottom of the intake manifold. Some of it may come from the PCV hoses and some may actually be unburnt gasoline which has come up from the intake manifold. Since the Prius engine runs on the Atkinson cycle, the compression stroke starts while the intake valves are still open, which forces a fraction of the air/fuel mixture within the cylinder back into the intake manifold.

 

How can you determine if it has actually failed?


iPhone ?

 

The engine ECU logs a DTC directly associated with the MAF sensor.

For example, P0100, P0102 or P0103 which relates to the mass air flow sensor circuit being open or shorted; P0101 where the air flow reported by the sensor does not make sense given the throttle position and engine speed; or P0110, P0112 or P0113 where the air temperature sensor which is part of the MAF sensor has an open or short.

These codes are rare. Usually the issue is that the MAF sensor gets coated with dirt (due to inadequate air filtration), hence the engine ECU is not able to properly control the air/fuel mixture and the engine therefore displays poor power or a no-start.

 

That is awesome news! Read some of my posts on this forum and you will find I have the same thing going on with my car… Runs fine… Runs poorly or not at all… Runs fine. I will just make a comment to add on to Paul's post above… I did get a remanufactured battery… And it has been replaced twice under warranty. Prior to needing that battery replacement I never had any of this intermittent trouble with the car.


iPhone ?

 

On a third start, the indicator lights go away but the codes remain in memory. This suggests the problem is intermittent.

I recommend clearing the codes anyway. That way you'll not have 'stale' codes hanging around that might lead to a 'cleared while testing' non-fault.

Bob Wilson

 

Clear codes how Bob? I remember taking the 12 volt battery out for a time, but I forgot

I remember though that the MAF sensor is very fragile, so y'all be gentle there.

Usta be a Mercedes M180 engine in my life. Two carbs. I balanced their air flow with a research grade MAF, Cost about a zillion bucks. Boss said "sure you can borrow it. Break it and buy me a new one"

 

Well, that is not helping the situation. Look at the engine air filter when you work on the car, and replace it if you cannot see light through the paper element as you hold it up to the sun.

 

I had same situation. code was P3191. I cleaned TB and MAF, thinned the motor oil down with lower viscosity oil and bled out motor oil below fill line, but still got the same code on cold starts.

turned out that after not driving it a while, the 12v aux battery was losing charge and dying. replaced the aux battery, have not had the code since.

 

These stories give me hope! Great job!


iPhone ?

 

This sounds almost exactly like what has been happening recently with my 2002: while driving, the accelerator suddenly does nothing... and the car gradually loses power and stops... (showing the triangle and the car symbol with the exclamation point). Usually the vehicle will restart and drive normally. I was surprised last week, however, when i restarted the vehicle and the gas engine was idling nicely-- but it wouldn't respond to the accelerator (even though the gas engine continued to idle). That has only happened once... every other time, after the vehicle restarted, the accelerator functioned normally. Any ideas as to why that happened? All explanations will be appreciated.​

 

There are two well known (here) conditions:

• cold-start fails - engine turns over for ~10 seconds and stops with alarms. Second attempt often works for a while. The frequent cause is a sticky throttle plate which can be solved by cleaning. Mr Google can find many sources.
• "big hand" - the car slows to about 25 mph as if a big hand is holding the car back. It is due to 'noisy' accelerator encoder and can be fixed by cleaning or replacing. Again, Mr Google can find many sources.

These are distinct problems with separate resolutions.

GOOD LUCK!
Bob Wilson

 

Safely remote, I can clam that gen1tom @18 has an accel pedal potentiometer no longer living up to its potential.

Both Bob W and I used to fix these, but have moved on to lesser things.