Ignition dropping out causing nice missfire

[I A Motorsport]

Hi people

Fairly new to nistune, and been working through all sorts of issues with it, just working my way round the system..

I did have an issue where it seemed to be using prevous cell injection timing for a short period while in a higher cell.. very confusing, untill i read that Matt had seen this before and nissan ecu seems to use previous info from the cell an hold on to it for around 3 secs, so ive had to increase low down fuel to make the higher up come into spec.. just means a jump in fuling a bit early on.. well thats what ive done to get round it..

it started off as a missfire under load at around 5500rpm and has slowly got worse.

if i start a power run(dyno) it wont start till 5500rpm
if hit full throttle in neurtral i can get it to miss
if i hold it at high rpm in neutral constant i can also get the miss..
the car also runs at 10deg on idle (tps on)

it has gone away before but now seems to be constant
and when i say gone away i mean a miss high up but nothing in 0 load and also runs at 15 deg idle (tps on)

car specs/details
sr20der backtop vvt

tdo5 turbo
z32
740cc nismo
Splitfire coilpacks and ignitor pack
tomei 254 redtop cams so vvt removed
and the usual front mount, fuel pump, exhaust etc
3 bar fuel pressure with vac

ive changed maf and injectors for k costant and also changed the latancy to 660 for the nismo's
ive also set the timing correctly at 15deg and its not changed on its own
ive pulled plenty of ignition out as i had only just started on the rough maps
hadnt even checked my scales are good only got up to 1 bar and found this problem

ive change for know working
Afm
coil packs
ign amp
plugs

any ideas would be great... log and bin attached

i first lift the revs then blip hrottle 0 load .. see what you think

using 69f10

chris test 750 32.bin

(64 KiB) Downloaded 188 times

NIStune_2011-11-13_1650_13.csv

(56.75 KiB) Downloaded 215 times

[bachig24u]

log identifies is a free revving engine,
low alternator voltage,
tps voltage a little low. only measures to half throttle.
oxygen sensor faulty.

I hope I used the wrong address file to veiw the file.
load scales look really out of scope, 141% dutycycle.

a wild guess would be one of the sparkplug tips have melted by looking at that tune.

can you confirm the name of which address file you are using?

[I A Motorsport]

so where the log jumps up an down that seems all fine ? looked like a los of ignition timing
and you see no reason why its sitting at 10 deg early on ?

i used the address file..S14_SR20DET_512_E.adr

i had to adjust he ign and rpm load scales as a bar boost(200kpa) is now the middle of the map, and it went up to 96 after the rescaling for injecors and maf, planing on running 1.7 bar so you think i should leave it alone ? with the 96 go up that high in boost havnt yet tried cos i can with this miss..

plugs are fine change and swaped

[I A Motorsport]

here are few logs

i hve just noticed my injection timing goes up to 96 % at only 1 bar boost i know im running rich (10 afr) but i would exspect 740 to be lower than that ?

anyway logs below

NIStune_2011-11-11_0955_06.csv

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NIStune_2011-11-11_1004_18.csv

(21.31 KiB) Downloaded 162 times

NIStune_2011-11-11_2040_53.csv

(140.36 KiB) Downloaded 183 times

[I A Motorsport]

NIStune_2011-11-13_1553_31.csv

(33.55 KiB) Downloaded 147 times

[I A Motorsport]

could someone also explain what knock boost duty an high boost duty are ? this isnt in the manual

i could take a guess but the maps for them dont really add up

nisune doesnt seem to be an ignition/feedback hold.. for setting the timing. i know you can pull tps but alot of cars that come through that never works correctly as so many things have been messed with. or have i missed it

regards ian

[Matt]

NIStune_2011-11-11_0955_06.csv
From this log at 5587 i see TP (and injector time consequently) decreasing whilst RPMS ncrease rapidly and AFM voltage slowly increasing. At this point I can see the cursor pulling back in the maps whilst the AFRs in the map are getting richer. Would suggest pulling back the TP scalers since TP maxing at 94 but end of the scales being at 127 last three columns wont get 'read'

As for other logs similarly can see a reduction but not cut in injection time. Ignition TP scalers also need to be pulled back lower too

NIStune_2011-11-13_1650_13.csv
Yes can see idle speed RPM issue here. It is fluctuating between 10 and 15 deg BDTC. Now car is about 81 degC coolant temp so no other maps in play here. What I dare say is that it is the target RPM coming into effect here

Target RPM is 700rpm at 80 degC coolant temp. If its higher than this then the ECU might be dropping 5 deg timing to reach the target. Once its around this then resumes back to 15 deg BDTC in the idle/decel timing table

As for misfire

Splitfire coilpacks and ignitor pack

Despite potentially leaning out a little at the top end (sorry dont know your AFRs here at those points) I would say it could be a physical ignition issue since everything looks fine otherwise in the log at this point in time

[I A Motorsport]

Thanks for the info

I'm only running 1 bar of boost at the moment I will be running it up to 1.7 bar. So I though rescaling would Need doing ? As like you said reading 94 now with only 1bar. (94 was the original end of scale before I adjusted )

I assume what I have done in the load scalers will allow the tp to rise once I increase boost?


Missfire wise.

I have swaped
Coil packs
Plugs
Ign amp
Afm

I'm sure your right. And ATM working though I think one of the injectors breaking down.

[Matt]

Would have to look at your MAF voltage again. Will only know once you hit higher boost but might be okay in that circumstance

[I A Motorsport]

I have removed vtc

Installed red top cams ( tomei poncams 252 I think) and pulleys timed in as stock)
Vtc solenoid still installed but not pluged in.

Is there anything in the ecu I have to turn off ?

Regards Ian

[I A Motorsport]

right well i have no idea whats causing this miss. im basically left with, as the only things i havnt swaped out!


faulty cas
injectors
or bad batch of fuel


here is a log of me trying to rev it ..its now to the point it wont even idle properly reving cleanly is something of the past..

i dont have an ecu to try,

NIStune_2011-11-16_1622_44.csv

(28.31 KiB) Downloaded 182 times

[I A Motorsport]

Ok got another ecu. 75f00

Loaded base image
Changes maf and injectors.

Won't even start the car and back fired like timing is out.

It's not. I've rechecked 3 times with CAS timing and cam timing.

Put the original ecu back in runs up after a bit of trying ( guessing fuel in cyl)
Runs but missfires

Any ideas ?

[Eric]

What kind of plugs are you using and have you tried re-gapping the plugs ?

I'm not a big fan of splitfire coils myself...my personal experience (for the Z32 at least) is they seem to cause a lot of misfires in a similar way as you describe

[I A Motorsport]

To end this thread as so many never are.

Basically I changed the plugs because of a missfire high up on boost.
New plugs ngk7 gaped to 0.8
Still had missfire. Was chasing down. And not realising the over time te new plugs where breaking down to the point of just arcing down themselves and not actually jumping the gap.

Now unfortunatly I have no idea why. Put the original plugs back in. And all missfires are gone !!!!! Go figure ?!

Still running the spitfires and there igniter box wiring loom setup.
Not really sure why they have a loom using a new igniter box and still uses the original ignitor aswell. Seems odd unless it's not an ignitor boys and something else. ?!