Inj. Duty Cycle?
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Open loop? Open loop means the computer is not responding to its own control, just the look up tables from the sensor readings. Closed loop is the scale back. The oxygen sensor is monitored, and air fuel adjustments are made from it.
Open loop is when fuel is "dumped". You can't be at wide open throttle (WOT) and be in closed loop.
100% duty cycle isn't something that will happen. The injector can't always be on. At 94% you are about as far as you can take the injector.
Open loop is when fuel is "dumped". You can't be at wide open throttle (WOT) and be in closed loop.
100% duty cycle isn't something that will happen. The injector can't always be on. At 94% you are about as far as you can take the injector.
85% or less, any higher and you need to start shopping for new injectors (assuming your A/F's are reasonable).
Nick M said:
Exactly, so how does the computer decide what percentage the inj. duty cycle should be at WOT. I'm not adding any fuel so why does my car go to 94% when you guys say 85% is the safe limit.
If it is strictly based on the preset tables does this mean toyota wrote a table from the factory to run injectors at maximum DC in open loop?
The TCCS engineers decided it based on VE of the engine, and injector size.inline6 said:
Under what circumstances? The ECU fuel trim is going richer trying to correct what it sees as lean. You have a turbo 7MGE? Stock injectors are about 320cc GE or 440cc GTE
Fuel trim is an attempt to compensate for driving style and wear and tear. The tables can and do change.
Its a 1jz on the stock injectors 370cc. I guess I'm confused about the fuel tables because I thought it gets no feedback from the o2 sensor in open loop so I didn't know it could "see it as lean".Nick M said:
I thought the fuel trimming was to trim base tables for regular driving, to get in a close range, then let the o2 sensor get it right on.
Thanks for the info, I'm trying to understand exactly what the car is trying to do, so I know how it will react when I make it do what I want it to do through the emanage, or anything else.
You are posting in the wrong section. The harder or softer you drive, the more the table will change. Oxygen sensor feedback is an emission function that keeps the catalytic converter in its optimum range.
I can not confirm anything on 1JZ engine control. It was not sold in the US, and there is/was no training.
I don't think there would be massive differences though.
I don't think there would be massive differences though.
inline6 said:
Older post but I thought I would try and answer your question.
Duty cycle is the % of on time compared to the off time of a cycle. The computer doesn't use duty cycle, it is just a way to measure the on time. It uses a pulse width to control the injectors. You will have a PW of around 1.7-2ms at idle depending on injector size and at high boost, high rpm(red line) it could be around 15ms and 90%dc. 15ms would have a lower dc at a lower rpm but at 7000rpms it is near 100%. On stand alone systems you can tell the ECU it needs x amount of fuel and it will give you that pulse width and you can run push an injector over 100% dc even though it is maxed out, I have. When I had the stock ecu, just before the rev limited fuel cut I measured 96%dc. Your DC is only that high neasr redline. It would be different if they were operated that high constantly.
It is fine to run up to 95 percent dc on side feed injectors like those in the 1jz. The thing about side feeds is the fuel coming in from all around keeps the coil from overheating.
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