gas problem

[JDM AE92]

hey guys before i bought my 92 corolla 4afe back in June i think the last owner who had changed the engine now it takes up a lot of gas and the smell is very rich i also hear a vacuum leak what do u think the problem is?

[SCT]

A vacuum leak... Source the leak out by listening. If still difficult, brake cleaner or carb cleaner. Spray in small areas. If there's a change in the way the motor is running when you spray in a certain area, the leak is there somewhere.

Not sure if there's an adjustment for idle, haven't tooled a 4AFE, never had one.

[JDM AE92]

Originally Posted by SCT

A vacuum leak... Source the leak out by listening. If still difficult, brake cleaner or carb cleaner. Spray in small areas. If there's a change in the way the motor is running when you spray in a certain area, the leak is there somewhere.

Not sure if there's an adjustment for idle, haven't tooled a 4AFE, never had one.

thanks man ill try that and see where it takes me

[Kiwi-Corolla]

Originally Posted by SCT

Not sure if there's an adjustment for idle, haven't tooled a 4AFE, never had one.

The idle adjustment for a 4A-FE is all controlled through the ECU. You can put a nut on the screw that rests against the accelerator butterfly which makes the idle rise slightly, but it doesn't stay that way for long because the ECU automatically reprograms itself.

[Mr.Nutcase]

if it running rich, then a vacuum leak would cause a car to run lean.
A rich mixture has more gas than air(OXYGEN), it cooler than lean
A lean mixture has more oxygen that gas..., it runs hotter than rich
No codes (DTC's)?
Maybe a bad 02 sensor
check it......

[JDM AE92]

thanks man ill go check those out btw i have nno codes all i hear is a vacuum leak somewhere

[Mr.Nutcase]

Originally Posted by JDM AE92

thanks man ill go check those out btw i have nno codes all i hear is a vacuum leak somewhere

To check a vac leak, use break cleaner/
or if you have AC sniffer you can you that find leaks...
Pull the vacuum hose of fuel regulator, if you find fuel in the vacuum hose, then the regulator is leaking..

[JDM AE92]

alright ill check that out to

[Donald]

Originally Posted by Kiwi-Corolla

The idle adjustment for a 4A-FE is all controlled through the ECU. You can put a nut on the screw that rests against the accelerator butterfly which makes the idle rise slightly, but it doesn't stay that way for long because the ECU automatically reprograms itself.

Sorry, incorrect.
On the throttle body, there is a brass screw (probably covered with an aluminum plug).

Drill a small hole into the plug. You will know as soon as you go through the plug. It is only about 1/16" thick. Screw in a self tapping screw, just enough to be secure into the plug. Pull on the screw with a pair of vicegrip pliers, or something similar, to remove the plug.

After getting the engine to normal operating temperature, you bridge the E1 and TE1 terminals in the "check engine connector" box, then adjust this screw to set the idle speed.

[Kiwi-Corolla]

Originally Posted by Donald

Sorry, incorrect.
On the throttle body, there is a brass screw (probably covered with an aluminum plug).

Drill a small hole into the plug. You will know as soon as you go through the plug. It is only about 1/16" thick. Screw in a self tapping screw, just enough to be secure into the plug. Pull on the screw with a pair of vicegrip pliers, or something similar, to remove the plug.

After getting the engine to normal operating temperature, you bridge the E1 and TE1 terminals in the "check engine connector" box, then adjust this screw to set the idle speed.

Interesting! When I was trying to increase my idle speed I rang around various mechanics, including two different Toyota dealerships and they all said that it wasn't possible to increase the idle speed as it is all controlled via the ECU. I even took my car to the dealership one day to get their opinion in person and they said the same thing.

I'll try out what you said and see if it makes a difference. Cheers for the info.

[Donald]

The AE101 and newer are totally computer controlled, but the AE92, AE86 and AE82 are adjustable.
Well, let me clarify that, the US models are adjustable. I'm not sure about the NZ models. Toyota has a way of having totally different setups in the sam model in different markets.