Badgaz

interesting.... you could spend a couple of hundred dollars on a fc datalogit so that you can save your tune to a laptop....this is what is available on all the other ecu platforms...however not many of them have this handy dandy hand controller.

have you tried this first? http://www.skylinesaustralia.com/forums/topic/113284-fixing-your-rb26-afms/page-3?hl=%2Bdry+%2Bsolder#entry6020391

check here.... http://www.skylinesaustralia.com/forums/topic/251093-nismo-afm-flow-same-as-z32-afm/

Paul's Faq point states that it is NVRAM (non volatile ram) old ECU's use EPROM which is Erasable Programmable Read Only Memory, they are wiped by removal of the sticker over the IC and put under an ultraviolet light which resets all the gates...effectively wiping the chip.

its not outside the possibility i suppose but given the OP it seems unlikely.

they don't normally just 'lose' there tune information which is written to a EEPROM or similar chip inside the ECU...are you sure there isn't something else causing the problem? like a hose clamp not tightened properly or a hose split?

you could give them a good clean as a first step, then if they still cause problems you could open them up and resolder any dry solder joints inside the afms. (there is a DIY here somewhere) alternatively you could change to rb25 afms or z32 afms. 5.1 volts is the maximum voltage the afms will show, so this may be what the engine check light is flashing for.

the power fc has threshold warnings which will flash the engine check light when either one of them is reached....off the top of my head there is airflow voltage warning. injector warning, boost(if hooked up), knock. it's probably the afm as they are a common fault.

is it the black or beige version?

You can also get an FC Datalogit which will allow the handcontroller port to be used to interface to a pc with some software.....much easier than using the hand controller to adjust the tune.

Here is a new graph.

-Apexi Power FC -1.2bar boost via blitz sbc -PULP 98 -850cc injectors (remanufactured) -GTR Fuel pump -High flowed stock turbo (Steel t3 turbine, largest front wheel could fit) -3" exhaust from down pipe back (3" coby resonator >3"RPS muffler) 229rwkw @ 16psi sorry about the graph, but you get the idea.

yes agreed there is the theoretical world and the real world...my lag values had a correction of 0.29 at 14volts from the manufacturer....it idled a little crappy and i adjusted the correction to 0.31 and it idles perfect....just like they were suppose to be 850's but i'm working off a correction factor that is 52% which puts them around 750cc. 1k is what we'd pay over here in NZ for a set of 740's.

they idle fine if you get your lag time right in your corrections....thats why its important to know.....and i get about 400+km to a tank. i'm pretty pleased i didn't piss $1000 up against the wall when there are injectors out there that will do the job for a third the price.

she went on the dyno today. made 229kw @ 16psi. boost peaked early at 19psi then tapered down through to redline....turbo ran out of puff.

I'm running some of those remanufactured 850s from tlf performance. it goes on the dyno tomorrow....hoping for the best.

score! don't forget to get the lag times....you'll need them when for when you tune.....I'd advise you to put them straight in after the cleaning and flowing as mine got stuck after not putting them in after a full bench flow and test and multiple ultrasonic baths...I only waited 2 months.

you need to set your base timing....if you don't know what that is....then i'd suggest you take it to a mechanic to check or alternatively learn how to do it from these forums... base timing is where the engine ignition advance starts....This is usually 15 degrees Before Top Dead Centre.for the rb25det. as others have said nistune for r33's isn't straight forward as you need to start with a different ecu from the get go. (z32 one is best) you'd be best going for an aftermarket one like the adaptronic or powerfc or haltech etc.

have you checked that your base timing is at 15 degrees?

so what are the knock sensors for then? i guess i might be using 'closed loop' in a broader sense and not just the fuel mixture sense.

i'll guess nismo 740's let us know what they flow don't forget to get your pulse width measured if they can.

i also assume you have tried to search for the millions of 4000-5000rpm misfire threads....i'd recommend a powefc...yes i'm a little bias but you get the handy controller which allows you to see your sensor functions and also change your settings on the fly....i use mine to set my rev limit to 500rpm when i'm parked at the shops or in an area i don't trust.

yeah while i don't disagree with you the factory ecu does a pretty good job, i just thought it was a strange place to jump to when there isn't really any modifications he has that necessitate the aftermarket ecu, with no closed loop protection from the factory ecu you rely heavily on the tuner....so if you do go ahead with one make sure you tell the tuner how you want your car to be and feel e.g safe tune not at limites responsive etc.

how much did you up the boost to?

what mods do you actually have to change from stock ecu for?