over fueling

[johnsupra]

what can cause a supra to over fuel really bad i have tried ecu ,map sensor ,tps ,injectors ,plugs coilpacks and conectors and checked every vacume hose and intercooler hose

[Darket]

Change the oxygen sensor (lambda) .. dont buy a cheapo after market one get a genuine one and make sure the shims are in spec .. the latter wont cause over fueling but its something you havent checked and is one of the most neglected service tasks on a supra and if neglected one of the most damaging ones

Also if its over fueling dont drive it .. it will dilute your oil and cause no end of damage

[johnsupra]

its over fueling that it wont drive i can see the petrol coming out between the y pipe and dowd pipe

[Darket]

Ok that sounds bad .... did you check that it was firing on all the coils ?

[johnsupra]

ya its firing on all it wont pass 3000 rpm it starts to die

[Darket]

are you getting an engine check light ?.... if not and i know its silly but does the engine check light illuminate when you first switch on the ignition if not it maybe a blown bulb ?... have you checked for codes ? .. you said you checked the ecu and the map sensor ? how did you check them ? did you swap them out ? if so were they known good units ?.. JZA70 ecu's are notorious for capacitor leakage and failing sometimes without warning.

Sorry for all the questions but we need as much detail as possiable .... is the fuel system modded in any way etc etc

[johnsupra]

are you getting an engine check light ?.... if not and i know its silly but does the engine check light illuminate when you first switch on the ignition if not it maybe a blown bulb ?... have you checked for codes ? .. you said you checked the ecu and the map sensor ? how did you check them ? did you swap them out ? if so were they known good units ?.. JZA70 ecu's are notorious for capacitor leakage and failing sometimes without warning.

Sorry for all the questions but we need as much detail as possiable .... is the fuel system modded in any way etc etc

ya the engine check light is working and their is no cods coming up .ya i swaped all the parts out of a running car .there is no mods done to the fueling the only mods to the car is exhaust and down pipe

[supradupra.com]

As well as Ed's advice this also has traits of a stuck open injector.

[johnsupra]

As well as Ed's advice this also has traits of a stuck open injector.

i tried all the injectors changed then all out and made no difference

[Darket]

Have you done a compression test ?... what about a simple wiring fault ?

[johnsupra]

Have you done a compression test ?... what about a simple wiring fault ?

no i havent done a compression test.would the car do this if the engine was f**ked .what kind of wiring fault could it be .wat reading should the compression be

[thevork]

JZA70 ecu's are notorious for capacitor leakage and failing sometimes without warning.



this is very true. Happened to a friend of mine.
So the ECU was also swapped for a known good one?

If the ecu is good and the injectors are good too, it seems to me you've got some bad wiring somewhere.

Can you disconnect the wires one by one with the engine idling (be carefull!) to pinpoint your problem to a certain cilinder?

[johnsupra]

this is very true. Happened to a friend of mine.
So the ECU was also swapped for a known good one?

If the ecu is good and the injectors are good too, it seems to me you've got some bad wiring somewhere.

Can you disconnect the wires one by one with the engine idling (be carefull!) to pinpoint your problem to a certain cilinder?

disconnect which wires