99.6% Injector Duty at 45.5% Throttle = bad times...

[TRDcelica90]

Pic taken of my AVC-R that held the peak of each variable while i was driving to Jaycar this morning.. No i wasn't thrashing it and no my car isnt amazingly powerful. as you can also see from the revs i was babying the car there because it was running like crap.

The car is a 90 Gt-Four with the RC 3sgte on stock ECU, I have been having a lot of trouble with it running lean at times and it is very intermittent. Last Saturday drove it to Kinglake (1 Hr one way) and back and didnt have a problem. Then the next day the engine light was on the entire time for a 15min drive, checked the error codes and all it did was run the fuel pump constantly until i realised that it was leaking fuel from the FPR. Tightened that all up and was fine.

Today had the engine light flash up for maybe 5 seconds while i was warming up the car and then it went away?? no codes but seems to do this a bit lately?? but no codes...

I have changed every plug, rotor cap, dizzy, leads and AFM.

This car shits me to tears sometimes, any ideas would be great. thanks!!

[Hen]

I often find the peak duty cycle goes abnormally high while starting (admittedly on a Wolf). As in, whenever I check the "datalogging" it's at or near 100%. But if I start the car and reset the datalog then I see more realistic values.

Worth checking before getting too stressed about it.

[TRDcelica90]

Nah it was genuinely running like crap, it started off way lower starting the car, everytime it would buck or shudder while driving it would jump up higher. maybe an AFM issue reading too much air??

[TRDcelica90]

Ok so after tightening the FPR and clamping the hose i got 2 error codes.. 24 and 31.. Air intake temp sensor and AFM open circuit..

Looks like i need a new AFM

[TRDcelica90]

[OnAll-FOUR]

Not sure what that last pic is

How does the AVC-R work? is it an interceptor?

[TRDcelica90]

Last picture is the IAT sensor that's in the AFM.. Looking pretty sad..

I'm not sure about the avcr or what you mean haha

[lexsmaz]

I saw your post on another thread on replacing the air temp sensor, I didn't think the air temp sensor played such a big part in Toyota mixtures, I would be looking at the open circuit in the AFM that you said also showed up as you said sounds like time for a New AFM & have you checked the fuel pump pressure too, could be a poor pump or faulty oxy sensor ..

[jonathan yee]

Not sure what that last pic is

How does the AVC-R work? is it an interceptor?

Avcr is just a boost controller that also taps into various wires to give read outs like rpm and inj duty, but it doesnt alter them in anyway.

[motard_mike]

i had a similar thing on my 1ggte, it was running factory turbos on 16psi with factory ecu and a piggy back interceptor style ecu.
on the dyno it was showing near 100% duty cycle on the avcr or whatever it is. then i went singe turbo and same setup and it was making max duty cycle at like 12 psi and 4000 rpm or something. now im running exactly the same fuel system and injectors with an aftermarket ecu and no other significant changes and im running 22psi to redline with perfect air fuel ratios and not near max injector duty cycle.........
i have no idea how thats possible but id say the avcr screen thing is not telling you the full story. after the info it spat out for me and my setup i wouldnt trust it.
whats your fuel economy like?

[OnAll-FOUR]

I can't think of what would cause the ecu to change the injector duty so much? Normal operation all ECUs operate of a fixed map unless in cruise, and while on cruise you should never see 100%.

If AFM is dead, the safe mode for the ecu would be to open injectors max fuel and give a limp home mode which sounds the most likely.

Or the avc-r is giving you bogus results. A lot of factors could influence the injector duty readings depending on how it is hooked up.

[TRDcelica90]

The AVR-c might not be 100% correct but even without it i know im having a fuel issue. The car does seem like it is in limp mode, so the code 32 is open circuit in the AFM be from the code 24 with the broken IAT sensor or ould it be another problem again?? seems weird the car runs like absolute shit because the air temp sensor is gone.. but i spose its making sure there is no detonation

Motormike I havent actually been able to get through a full tank in ages so dont know yet

[jonathan yee]

I think the open cicuit would be something more than the iat sensor.

Tried a non grpA afm just to test? It could be the ecu itself. Had a gen3 ecu saying issue with map sensor, but it was the map sensor circuit in the ecu itself.

[TRDcelica90]

Update, took the AFM to a local EFI specialist and got my afm tested.. Ended up being 100% in hot and cold conditions.

Frustrating but at least rules it out.

What other sensor or problem could be causing this?? Leads plugs, dizzy and rotor are all in good condition

[jonathan yee]

Could be the ecu itself. Or dodgy O2 sensor. Disconnect the O2 sensor, itll throw a cel but wont affect running.

If theres no O2 sensor it runs fine, but if the O2 sensor is dodgy and sending random wrong signalsthen it can mess with the ecu. So try disconnecting and see if runs any different.