'85 convertible only runs when cold

[flimflambbq]

I've got a really strange problem. I have an '85 celica GT convertible with a 22RE motor, and was driving it one day last fall when the engine started to chug and hesitate. The problem got worse and worse from the drive home until the car was undriveable by the end of the day. It's to the point where the engine will turnover, run for maybe a second, and then stall out. Once in awhile it will idle for some 20 or 30 seconds, but when stalls out immediately when given throttle.

Now the weird part is, the car starts and runs entirely as intended in very cold weather, cold enough to warrant a high idle. As soon as the car warms up though, and the high idle kicks out, the engine has the same problem and eventually stalls out, or, stalls out immediately when given throttle.

First thing I replaced was the fuel filter, before I knew the car ran fine in cold weather. I've tried opening up the air flow meter to trick the engine into giving more gas, and this allows the car to idle steady, but again stall out when given any throttle. As far as I can tell, there seems to be a problem with the ECU telling the injectors just how much gas to give the mixture, but whether it's the ECU itself or another component up the line I don't know.

Anyone ever encounter this before? Any idea why it would run just fine in cold weather high idle but die when it warms up? Does anyone know exactly what the engine does differently during a high idle than it does during normal running? Any help would be greatly appreciated. I'm at my wits end and if I can't come to any conclusions it's just going to be a free-for-all parts replacement with anything engine mixture related under the hood.

[stepho]

Hmm, sounds like the air fuel ratio is screwed up.
Sounds like it is giving too little fuel for the given amount of air or it thinks there is only a little amount of air coming in.
As a double check, there should NOT be a heavy fuel smell (otherwise I'm barking up the wrong tree).

Likely causes are
1. screwed up air flow measurement.
I forgot, is the 22R-E AFM or MAP?
Anyway check the wires to which ever one it is and also the throttle position sensor.
But since you said you could alter the idle speed by adjusting the air flow measurement, this part is probably okay.

2. bad fuel management.
Bad wiring to the injectors, bad wiring to the injector resisitor pack or bad injectors.
Or good old bad earth connection for the computer and associated EFI sensors.

Can you tell me what you think of your convertible? Is yours the factory version or an aftermarket conversion? They are extremely rare here in Australia. I have brochures for it (both factory and aftermarket) but I have never seen one with my own eyes.

- Stepho

[tommy8768]

your cold start injector time switch is most likely bad. When they die they dump the extra fuel thats normally required only on a cold start-all of the time. replace that and you should be ok.

[johnnyboy25years]

i had this same problem with my 22r i would replace your coolent tempeture sensor there very cheap and about 10 min to do i bet that will fix the problem.