Injector response time
11-20-2009, 08:38 AM
#21
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Okay, after more wasted hours of my life I can state that FIC inj response time is not the additional lag time of aftermarket inj's over stock lag time. What needs to be entered here is a value between stock inj response time and new inj response time. E.g; if stock inj's had .7ms lag time and new inj's have 1.2ms lag time, FIC IRT should be somewhere between .7 and 1.2ms, according to AEM.
You can tune around this in the fuel map, as most seem to do, but if you get this right at the start of tuning, it could mean less fuel map tweaking.
You can tune around this in the fuel map, as most seem to do, but if you get this right at the start of tuning, it could mean less fuel map tweaking.
11-20-2009, 04:10 PM
#24
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I'm just frustrated about all the time I've been spending on this mis-wired Boomslang harness, FIC bugginess and a little ticked that AEM phone support told me IRT should be just the diff between oe and new inj's. Then on their forum I find AEM saying IRT should be somewhere between oe and new inj's.
That's great info! Deatschwerks told me my 440cc lag time was 1270us at 13v and 1000us seems to be working for me. I also have a base map from Dezod and they used 1100us, presumably with 550cc.
Edit: Now I don't know who to believe. I tried going the other way (405us) and it seems to run and idle much better. OTOH, it might just be the ECU adapting to the new setup. I wish AEM would provide clearer instructions for FIC installation and tuning. One AEM tech says one thing and the next one contradicts him. The tech I spoke with today suggested that Scions don't benefit at all from resistors on the crk/cam signals and told me I should remove mine.
Edit: Now I don't know who to believe. I tried going the other way (405us) and it seems to run and idle much better. OTOH, it might just be the ECU adapting to the new setup. I wish AEM would provide clearer instructions for FIC installation and tuning. One AEM tech says one thing and the next one contradicts him. The tech I spoke with today suggested that Scions don't benefit at all from resistors on the crk/cam signals and told me I should remove mine.
Last edited by ScionFred; 11-21-2009 at 12:25 AM.
04-29-2010, 04:18 PM
#25
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05-07-2010, 11:09 AM
#27
anyone runnin the dezod 850s yet im currently tuning on them and ive got my response time set on .98 ms this is with the apr but gettin a good ltft of-.07 cruise and idle has stft of like +28 just wonderin if anyone has gottin some close numbers on these with the apr u adjust from 6v to 15v
05-07-2010, 12:39 PM
#29
im running the 850cc injectors as well...cant tell you trims cause im tuning open loop right now (aka no primary o2). after 50,000 miles, two turbo kits, and quite a bit of tuning it finally died on me.
05-08-2010, 04:34 PM
#33
poopy there pretty pricey i get 30% discount through my shop and i still gulped a lil buyin a new one cause toyota thought it was necessary to strip the thing when they assembled the car
07-06-2015, 04:08 PM
#34
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I'm bringing this up from the dead based on some research I've been doing on the AEM FIC. The injector response time seems to have the opposite effect than one would expect from what I'm reading.
Normally, I would have thought that you would increase this time if you are using larger injectors that generally take longer to open than stock, the thought being that it would add that additional pulse width to the injectors. However, it seems that instead this is being used for the FIC to determine the length of the injector pulse from the factor ECU to "ignore" before determining the percentage in increase or decrease the pulse width.
For instance, lets say the factory pulse width at a given load/rpm is 1ms, and you entered a IRT of .400ms. The FIC would subtract the .400 out, resulting in an "injector open" pulse width of .600ms. The fuel correction would then only be applied to this portion, so a -50% correction would pull out .300ms, yielding a total pulse length of 0.700ms (.3ms remaining after correction + the .4ms added back from the IRT).
Is my thinking correct?
Normally, I would have thought that you would increase this time if you are using larger injectors that generally take longer to open than stock, the thought being that it would add that additional pulse width to the injectors. However, it seems that instead this is being used for the FIC to determine the length of the injector pulse from the factor ECU to "ignore" before determining the percentage in increase or decrease the pulse width.
For instance, lets say the factory pulse width at a given load/rpm is 1ms, and you entered a IRT of .400ms. The FIC would subtract the .400 out, resulting in an "injector open" pulse width of .600ms. The fuel correction would then only be applied to this portion, so a -50% correction would pull out .300ms, yielding a total pulse length of 0.700ms (.3ms remaining after correction + the .4ms added back from the IRT).
Is my thinking correct?
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