Potential misfire?

Hi

im tuning a subaru after fitting new injectors.

the car is a project car so has long periods of not running between actually running haha

im getting an issue around 5000rpm that im struggling to decipher from the data what it actually is

initially i thought perhaps overboost but looking at the logs the map and afr look good but the ignition drops out from 17 degrees or so to minus 8 and then back to where it should be causing a sharktooth in log and this then obviously effects afr etc

i took the plugs out which are relatively new and gapped to 0.6mm but still no good

the car has a COP conversion and i cant see how all 4 coild would be failing unless one plug or coil could cause the issue?

i will attach a picture of the log showing just the ignition timing

i don't believe its knock as i from the settings the ignition should not be ramped in as fast

any info would be much appreciated before i fire a parts cannon at the car!

Hi!

not saying i will be a massive help, but do you have a log of the other parameters on the car?

I can pull them up although the ecu i have only logs

map, ignition,tps etc…no knock correction or feedback is logged

its speed density so pretty basic all air temps etc look good

the afr has a slight bounce but its after the stutter on ignition which is what is occuring first

im getting some plugs tomorrow so hopefully that will cure it

if not il have to start changing other parts without really proving a fault 🤦‍♂️

Are the injectors from a reputable source? Fuel and sensors are one thing I have learned not to skimp on (the hard way, unfortunately)

What ECU is the car running? Did the problem start only after you changed the injectors?

There could be a weird spot in the fuel map too, possibly? It may be helpful to see a log of everything

Iv sorted it now

after many hours of going over log i could see voltage dropping and also the erpm along with ignition was dropping out

i checked voltage on alternator and it was a bit low so to prive i hooked a battery charge up whilst stationary and it sorted it

left it on charge for an hour or so and i have clean rpm through to redline

didnt half have me scratching my bead though

i think either the alternator is a bit duff (it is potentially 30 years old) and possibky the battery could do with replacing

iv cleaned all the eartb points up and it seems better

many years ago though i put the battery in the boot and used welding earth cable for power…not sure if im getting a bit of a voltage drop or resistance in cables causing issues also

i will try the obvious with a new battery first and see how it gos, i may reduce the length of cable and fit battery behind passenger seat instead

im not too fussed on weight distribution currently as i just want it to work but i did get there in the end and my afr etc looks good up til now!

im not going to lie either…AI helped me sort a few bits for coil dwell time for example…i put voktage drop in and also input data where car seems to run at with voltage and it made a table to interpolate coil charge time perfectly…its actually better than the map i ooriginally paid for…this is why i did the course with hp though as all iv done is learn that what i paid for was half a job

cheers all for the help though

Nice work, i bet its satisfying to have it running well again. I have heard of alternator interference wreaking havoc on ecus, dropping voltage certainly wouldnt help either. Haha.

I know the Terminator X ecu's specify the battery for the main power to the ecu. Not sure if it would be the case for you or not, just thought it was interesting.

Glad you got it sorted!!