Help With Ls400 Engine Shutoff W/o Warning

[apex430]

Help!

I have a 1994 LS400. with about 170k miles on it.

All the maintenance and PMs are done on it on regular schedule.

It has performed flawlessly w/o any problems until today.

The engine just cut off 2x without any warnings.

Once when i was sitting at stop light.

the 2nd time when i was slowing down to make a right turn into the house.

Can anyone on the board help? has anyone experienced problems like this?

There are no waring lights, beeps, etc.

Batteries, radios works good. When problem happened i just restarted the car and it runs fine.

thanks in advance.

[vyhanh]

Hi,

Is your key in the ignition part of a heavy bunch of keys? Sometimes, a heavy key chain will have effect on the ignition switch.

VH

[apex430]

Hi,

Is your key in the ignition part of a heavy bunch of keys? Sometimes, a heavy key chain will have effect on the ignition switch.

VH

←

Nah, only 1 key on my chain. I thought it was just the powerlock/unlock on the key acting up...

engine and tranny iddle smooth though... i don't want to take it to dealer and get ripped off only to find out nothing they could diagnose.

[1990LS400]

The only times the engines on my LS's ever died, a bad battery was the cause. The battery on my 00 LS failed at about four years - the engine died when I made a right hand turn into a parking lot and hit a small pothole. Batteries on my first (90) LS usually failed at between three and four years with similar symtoms.

If your battery is over three years old, you might as well replace it.

[Arkansawyer]

The other possibility that I have read about is carbon build up on the TB plate.

Try pulling off the vacuum hose on top of the TB while it is running and shooting a little TB cleaner in there. Understand that this will cause the engine to die when you spray it in there.

Have done this myself and it remedied a hot start problem I had (carbon buildup). Make sure the cleaner is sensor safe.

[apex430]

thankyou both 1990ls400 and arkansawyer.

i'll check the battery... it may be more than 2yrs old.

also, what's a TB?

thanks

[prix]

i think he means the throttle body (??)

thankyou both 1990ls400 and arkansawyer.

i'll check the battery... it may be more than 2yrs old.

also, what's a TB?

thanks

←

[prix]

i would also take a look at the 'low idle, engine dies, jerking.." thread to see if that fits what's happening.

Help!

I have a 1994 LS400.  with about 170k miles on it.

All the maintenance and PMs are done on it on regular schedule.

It has performed flawlessly w/o any problems until today.

The engine just cut off 2x without any warnings.

Once when i was sitting at stop light.

the 2nd time when i was slowing down to make a right turn into the house.

Can anyone on the board help? has anyone experienced problems like this?

There are no waring lights, beeps, etc.

Batteries, radios works good.  When problem happened i just restarted the car and it runs fine.

thanks in advance.

←

[Arkansawyer]

Apologies. TB is the throttle body. If you follow the plastic tubing from the air filter to the engine. At the point where it connects to "metal" is the throttle body. There are two circular "flaps" inside there that control the amount of air that enters the engine. Sometimes carbon can buildup to the point where it affects idle air flow. The three vacuum connections are right above where the blades are located.

Take a look at this link for a better idea of what we're discussing.

http://www.lexls.com/tutorials/EFI/throttlebody.html

[pfleyva]

My 1994 was doing the same thing. It was related to the A/C cycling on and off. Cleaning the throttle body fixed the problem.

Good Luck

[apex430]

you are right, this happened when the ac is on (all be it in low speed).

I'll check the TB tonight. I'm driving it today w/o any problem so far.

Just in case, i'm going to change the batteries later to be safe.

thank you again.