HELP!! Need help trying to diagnose my 1997 Avalon!

[csdead808]

I have a 1997 Avalon XL and the problem is that when the vehicle is cold it starts up fine and drives fine but once it gets to operating temperature it shuts down and will not start again until cooled! I have changed the fuel pump, Filter, EFI Relay, EFI (opening circut relay) in the cab under the glove box, the MAF, and even changed the spark plugs and still get the same thing. Can anyone with any information help! the engine makes a bogging nosi like it's starving for air or fuel I'm not sure.

[hoosiercheetah]

Weird. I had a T-Bird that did the same thing. It was a 1980, and it was vapor locking. Not really a possibility with fuel injection, though.

Are you getting any engine codes? I know that the ECM monitors engine temp and makes adjustments based on that, and other factors. It sounds to me like a sensor somewhere is giving the computer a screwy number once it's warmed up, that the computer can't live with. Or perhaps the computer itself isn't doing it's job once it gets the higher temp numbers.

Have you checked to see if anyone makes a 4-barrel Holly conversion for the 1MZ? You could eliminate the computer altogether. That would solve a whole host of problems.

Ok, seriously though. It sounds like computer/sensor stuff to me. It might be worth the 50 dollars you'll get charged to have a dealership hook it up to their extra-fancy computer and diagnose the problem for you, then take it home and do the repair yourself. As I understand it, the dealers have access to software that can get more info from the cars computer than you can get with a simple code reader. I've used this approach with a lot of success in the past.

Good Luck!

[Jack Deth]

next time it dies, check the battery voltage.

[bob2]

crankshaft sensor.

[robcam13]

i agree with bob2

[denverdog]

i had a somewhat similar sitution with a buick lesabre that turned out to be the fuel pump. ran great until everything got hot, then it just died.