Mixture Adjustment?

[Andynor]

Can anyone help? I have a 1989 celica 2.0 gt 3s-ge engine & am and getting 14 MPG! The engine is running far too rich, black plugs etc. Where is the mixture adjustment?

[GT4 BOOSTER]

its preset via the ecu mate , most likely a sensor is knackered , does it have a cat convertor , if so maywell be the lambda sensor in the exhaust. try taking out the efi fuse count to 15 and replace it - good luck

[crashbang]

i had the same prob,

gave the car a good service.... oil,filter, plugs etc n it was fine. not sure why but it worked

[Uncle Bob]

Servicing the engine would make sence first, just in case its a blocked air filter or burnt out plugs :D .

[Andynor]

Can anyone help?  I have a 1989 celica 2.0 gt 3s-ge engine & am and getting 14 MPG!  The engine is running far too rich, black plugs etc. Where is the mixture adjustment?

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[Andynor]

its preset via the ecu mate , most likely a sensor is knackered , does it have a cat convertor , if so maywell be the lambda sensor in the exhaust. try taking out the efi fuse count to 15 and replace it - good luck

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Thanks for replies, No cat & I have tried resetting the ECU to no avail. I have checked emissions with a gas analyser ( 7.2) The movement on the adjuster only made a slight differnce and it only moves about half a turn before stopping. This is at the back of engine compartment slighlty on the right. Is this the right one? I suspect it is another sensor . The one that tells the engine the temp is up? . Looks like a ( expensive) trip to a main dealer!

[mikeb]

What sort of journeys are you doing. Mine will only return 17-18 mpg doing short journeys around town. And that's without thrashing it.

A 1989 celica will not have a cat, unless it is an import, but even then I doubt it has one. So it won't have a lambda sensor either.

I guess you have checked for fault codes already. This will tell you if a sensor is failed open or short circuit. It sounds like one of yours is failed somewhere in between though.

Assuming you have a gen 5 (89 was the changeover from 4 to 5), it could be throttle position sensor, air flow meter, water temp sensor, cold start injector time switch, air temp sensor. In my opinion it is least likely to be air temp sensor, and most likely to be to do with the cold start injector or water temp sensor. Try unplugging it, but it might not start from cold very well. If it makes a difference to fuel consumption, then it is likely the cold start injector timeswitch is at fault.

[crashbang]

my emisions were well over that before the service then they fell well within the mot target so give a good service 1st then take it to mr T n ask him to just find the fault but not fix it. a back st garage will b soooooooo much cheaper . especialy if they know wot mr toyota says

[Cubic Incubi]

*************************89*********************************

Not cat, no oxygen sensor (lamda), facelift gen 5's where the first celicas's to have these, some imports may have due to JAP imissions controls but show me a JDM Gen 4 GT and i'll dance the fandango.

anyway...

Mate, your burning way too much fuel which tells me that after the air flow meter, you are losing air somewhere, the ECU doesnt know this and is still sending the fuel it thinks will burn with the air, but the air is missing,...... so, after the air flow meter, check the rubber hose for a split, check your throttle body is bolted down properly.

if you aint got a air leak, check the gasket on the TVIS where it meets the head , take out the plugs and check they are the right ones, how old are the leads? when i aqcuired my gen 4 GT in march they had 1986 stamped on them.. check your panel filter, and the cold air feed pipe for blockages as mentioned but i very much doubt this is this cause, i reckon it is defo post air flow meter and is losing air..

the air flowmeter is the aluminium lump attached to my cone filter in the pic below..

hope that helps

[Kelvyn]

let the handbrake off before you drive Seriously though are the brakes binding at all?? If you have a sticking brake caliper then consumption will be bad. Is the clutch OK?? If the clutch is slipping that will seriously affect your fuel consumption. Chap I used to work with complained his wifes old style mini was only doing 15mpg, turned out the clutch was knackered. You'de think that having a screaming engine at 30mph would give it away, (they weren't very mechanically minded).