SR20VET misfire
 

Hi, just started facing this problem a few weeks back. Mine's a SR20DET with a VE conversion.

It sorts of misfire slightly at random times, usually after driving for a bit, it goes from like 1,100rpm to 900ish and AFR went up a little. It happens out of the blue. It could be idling at a traffic light, or just cruising. It will just misfire for a short while, like 2 to 3 seconds and then it goes off and everything would be back to normal.

I've changed new spark plugs, new coilpacks, checked the injectors resistance. I've also sent a datalog to my tuner which he didn't see anything that was off.

Could a faulty CAS cause this?

What is your ignition setup?

I'm using K20 type r coil packs, and NGK BKR8EIX spark plugs. That has been my setup all along. Is there any way to check on the CAS? Even if it's working fine most of the time?

https://ibb.co/cbD0TpL


Just an update, pulled the plugs out to check, it's running a little hot on cylinder 3, in order 4,3,2,1. I've sent the injectors for cleaning and testing, which seems to be fine.

Could improper valves sealing cause this? And intermittently, usually when hot?

how much power are you putting down? That heat range is a bit high but I also don't know your setup or psi

Running a SR20VE head with Kelford cams 184ST, supertech valvetrain. 1050 injector dynamics. Boosting around 1.6bar. About 380whp on a mainline dyno

Got the cams installed and tuned in June, ran beautiful for 4 months until this issue popped up. Pulled the plugs and found that number 3 is running hotter than the rest.

Sent the injectors for a test and clean. Seems to be spraying evenly and equally.

I would suppose this issue to be more consistent if it has something to do with the valves? It seems to only occur when the engine is hot and it comes and goes.

Can you data log your ignition map? I’d start by doing some pulls and checking the map across the board for issues in the tune. Have you gone through the harness to ensure proper connection?

I've tried data logging and sending the file to my tuner but he didn't see anything that was off. I do not know anything about tuning and ignition tables sorry. He suggested to change the CAS which I did and somehow or rather, it seems to work for a day or 2, then it happened again, just not that frequently. Checked the valve clearance and it was within spec as well.

Somehow I feel this might be an electrical issue than a hardware issue? Loose wires somewhere? It would be good if it was consistent and not randomly appear when Im driving, certainly makes things easier to figure out ugh