Hi All,
Im not new to Nistune but I am new to this paticular problem, so thought I would throw it up here and see if anyone can advise or relate.
Basically, had a bloke come round last night for a Nistune type 3 install into a redtop s13 50F00 ECU. The engine was running 850cc SARD's, a Z32, HKS GTRS and numerous other engine mods.
Upon installation, I found the ECU already had a daughterboard installed, which was VERY similar to a Nistune type 4 board (Had 2 x EEPROM's, 1 odd 1 even & what I can only assume is a multiplexer, I took pics of it if anyone is interested, its actually made by a company in Japan called GT WORKS http://www.gtworks.net/) so I removed this board and fit the type 3, CJ1 swap was already done for me.
Plugged the ecu back in, connected via Nistune no problem, sync'd the 50F00 map up to the ECU and then resized the INJ to 850cc, adjusted INJ dead time to 760ns and changed AFM to a Z32. Straight away the engine would not start, sounded totally dead like the coilpacks were disconnected.
Then I re-loaded the 50F00 map back into Nistune, re-sync'd the totally stock map up to the ECU and tried to start it without resizing INJ or changing AFM, and it started almost immeadiatly, but ran rough as guts (as expected).
I then shut the motor back off, resized AFM to Z32 and started her up again, ran much smoother but was seeing 10:1 AFR's at Idle (again, to be expected at this point).
I then shut it off, resized INJ to 850cc (which is K of around 17000) and adjusted INJ dead time to 760ns. And just like before, straight up, no engine life, wouldnt even so much as cough.
Then I tried different INJ dead times, tried stock (550), 600, 650, 700 etc etc and no luck. Just to get it to start again I had to reload the 50F00 map back into nistune and re-sync, resize AFM before it would even fire up.
The best I managed to get it to was resized for 550cc, INJ dead time set at 760 (which is correct figure for SARD 850's) and Z32 AFM. It would drive pretty well at this setting and more importantly would actually start, but idle & cruise AFR's were around the 12.5:1 mark. At these settings, I was seeing a K const of around 24000.
Literally, the minute I changed it below that figure, the car would continue to run, AFR's would stabilise around 14-15:1 but AS SOON as I shut the engine off, it would not start again.
This had & has me pretty stumped... started to think perhaps GT Works had modified some other areas of the ECU (ie hardware mods) and that might be playing silly buggers with Nistune but really im stabbing in the dark here.
Any ideas?
PS, hope this makes sense, feel free to ask me to clarify
Cheers,
Hayden
Issues with starting after K changes
Moderator: Matt
Re: Issues with starting after K changes
Hmmmmm. Somewhat unusual. But when you start going big on injectors everything gets a lot more critical.
OK, here's what I'd do.
With injectors that big you'll have to run pretty low values in the fuel maps - so start with 20 in all the high load cells.
Then get it started with whatever K constant works, once it's running quickly adjust K again to get it running smoothly (tick "auto" and then use the "+/-" keys to adjust K).
Take it for a run/load up on dyno and tweak K until you get around 12:1 under load.
Adjust latency to get low load/idle correct.
See if it starts OK then. If not then it's time to start playing in the cranking tables. First work out if it's getting too much or too little fuel. Go easy in cranking tables as it's easy to flood your engine.
Hope my ramblings are of some help!
Pete L
OK, here's what I'd do.
With injectors that big you'll have to run pretty low values in the fuel maps - so start with 20 in all the high load cells.
Then get it started with whatever K constant works, once it's running quickly adjust K again to get it running smoothly (tick "auto" and then use the "+/-" keys to adjust K).
Take it for a run/load up on dyno and tweak K until you get around 12:1 under load.
Adjust latency to get low load/idle correct.
See if it starts OK then. If not then it's time to start playing in the cranking tables. First work out if it's getting too much or too little fuel. Go easy in cranking tables as it's easy to flood your engine.
Hope my ramblings are of some help!
Pete L
Re: Issues with starting after K changes
Hey Pete,
Just wanted to clear this up, as after some final changes it ran sweet afterwards.
Kept the K const at around 23000, once I started to go below 24000 it started to get very fiddly but in the end car ran and more importantly continued to start pretty sweet. I believe the guy who tuned it was going to drop the values in the fuel map (as you suggested) and then fine tune the K const. Kept latency values the same.
So far so good though, just found this strange as Ive not had this problem with other squirters of this size.
Thanks,
Hayden.
Just wanted to clear this up, as after some final changes it ran sweet afterwards.
Kept the K const at around 23000, once I started to go below 24000 it started to get very fiddly but in the end car ran and more importantly continued to start pretty sweet. I believe the guy who tuned it was going to drop the values in the fuel map (as you suggested) and then fine tune the K const. Kept latency values the same.
So far so good though, just found this strange as Ive not had this problem with other squirters of this size.
Thanks,
Hayden.