1991 Es250 Stalling During Hot Weather

[Reallyfrustrated]

Hello everyone.

I have a 1991 ES250 with 95K miles. It is in great shape and has been properly maintained it's entire life.

The past 2 years I have had a problem with the car stalling, and refusing to restart.

This ONLY happens occasionally, and ONLY during very hot weather (95+ degrees) when the AC is on , usually during stop and go traffic. The car will begin to backfire, and then lose power and die. When you try to restart it, it will immediately sputter and die again. After the car sits a while (usually 10-45 minutes) it will start again and drive perfectly. The temperature guage always shows the car is operating at the correct temperature, and is not overheating.

I have taken it to my mechanic twice, but of course it will not stall in his presence, so he cannot diagnose it.

Please help me! I otherwise love the car, and would hate to have to get rid of it. Thanks!!

[Toysrme]

1) Check for vacuum leaks

2) Clean the IAC valve (& EGR if your 2vz-fe has one)

3) Check for good spark (Rotor & cap)

4) Check timing

Most people would tell you to check the fuel pump, but with only 95,000 m on that Denso pump, you've probably got another 15 years on it.

[Reallyfrustrated]

Hi. Thanks for info. The things you described, are these things that would only fail during hot weather? The temperature is DEFINITELY an issue....

[Toysrme]

Reallyfrustrated, they can all be affected by the weather.

LEXUS OF RAMRAT, you're more annoying than my dog's !Removed! with roids.

[Toysrme]

Please come prepaired for class tomorrow people, you're not undergrads!

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[lenore]

Has the fuel filter been changed?

[Reallyfrustrated]

Yes, I had the fuel filter changed recently. That couldn't be affected by temperature, could it?

[Toysrme]

Nope.

[ArmyofOne]

Nope.

←

this is gonna sound funny, but you said the car was perfectly maintianed. however, alot (and i do me ALOT, as in the VAST majority) of owners (not lexus, but car owners in general) overlook the fact that the intake needs cleaning regularly. the UIM (upper Intake Manifold...the big silver thing on the very top of the engine, that the intake hose feeds into) has whats cvalled a butterfly valve inside fo the throttle body. sometimes, in hot temps, if this valve is gunked up, the car will not idle normally, it may "choke" resulting in a stall or backfire and then a stall.

to fix, simply take off the intake hose from the MAF (at the air filter box) and at the throttle body (on the other end). then spray Throttle body cleaner inside the Throttle body, first with the valve closed. then wipe off with a rag.

then pull on the accelerator cable (MAKE SURE THE ENGINE IS OFF) and the valve will rotate to a flat position paralell with the surface of the earth LOL. the side facing up is the side thats gets really gunked. clean that off with the intake cleaner, and spray it liberally (not so much that you flood the engine though) into the intake manifold, beyond that valve. then start your engine with the hose still disconnected (yes it will start, and sound alot better) and spray inside it again. please note that when you rotate the butterfly valve with the engine running, it will REV as it is connected to the accelerator cable and linkage. if the engine stalls and dies, no problem, get in and start it again.

ill bet it solves your problem, and if it doesnt, ill bet it helps, probably needed done anyway on a car thats 14 years old.

if your asking how i know, i owned one of the first ES250's to come off of the assembly line. :)

also, another thing you can do... take out your spark plugs individually, and spray throttle body/carbeuratir cleaner in the cylinders. just a quick squirt. this wil loosen up alot of the carbon on the tops of the pistons and the valves.

the entire process of cleaning the upper intake takes half an hour maybe. and will save you some $$$. carbuerator and choke cleaner will work too.

[91L3xus]

My ES used to do that also, but I rarely use A/C so I figured that's not the problem. The rubber hose that leads from the back of the AFM to the throttle body is where your sputtering and stalling problem starts. Make sure to tighten that circular clamp that holds the rubber tube to the throttle body, or you'll get a extremely rough idle that will eventually sputter out. Hence the vaccum leak.

Hope you get your problem fixed, and if you're looking for parts to start modding your ES, look into an EXS filter on eBay; they don't really add much power (or any at all as some might say), but they sound really cool. Lol.

[Reallyfrustrated]

I want to thank all you guys for the great suggestions.

As it turns out, this time the car DID stall while at my mechanics, and we were able to determine that the problem was in fact the fuel pump.

However I will be taking advantage of all the great maintainence tips you gentlemen provided. Thanks!

[Toysrme]

Wow that's crazy!

First time for everything I guess!