IGN Knock

Hello everyone,

Yes, I am new here. Last year we built a K Series motor swap for the race car i have. Overall we did well. Had some misfiring issues after some weeks and did a lot of changes. Did not have the money to go back to the tuner at the time. I've been watching videos and learning a lot. We found many issues and i was able to get them taken care of.

Now we did a full rebuild of the motor and getting it ready for Dyno. I know i can do what is needed. But I don't have the equipment like a dyno. I have always relied on data logs.

Now that i have been taking courses here, im starting to understand it even more. Last year i listened to my brother-in-law about disabling the knock sensor. This year we are not.

I'm trying to get ready for the dyno day I am going to have. I wanted to play around with the tune a little to help put in affect what I have learned here. My issue is, IGN Knock. I have reduced the ignition timming all the way down to 1 at idle, left the knock limit and knock retard where it is was and i can't seem to get rid of the ecu seeing the knock. I added fuel. It starts egtting better and almost fully stops. But now, it richer then can be and my eyes start watering. let along the AFR reading in the 11's(No I have not changed this to Lamda yet). We just got the car running. I can't race the car that rich.

I am using KTuner for the ECU addon. This is the one that is right on the board. Similar to KPro. Sad, but there is not always good explanations of what is what and what does what. I'm starting to wonder if for some reason i am getting phantom knocking. Just sitting there at idle taking all of the timing out, and adding fuel, i am still getting knock. I do wonder if i need to change the knock sensitivity in the tune. If so, do I go up in number or go down? I would liek to assume(i dont always like to assume as it can be bad) adding to the bas numbers that the tunes start with make it more sensitive. But i am not fully sure.

I don't know what all else to do to try and get rid of the knock. Its not fuel.

I am on 110 octane. 12.5-13:1 compression, BC 3.2 Cams, 88mm bore pistons, k24 block, k20a3 head ported lightly. Right now i dont have time or the extra money to get a external knock detection system as i have spent everything extra i had on getting this car done before the first race in 2 weeks.

So by chance, could it be phantom knock?

I would say the knock sensitivity isn't correct. I think you need to actually induce knock (which requires load) to set the sensitivity and thresholds correctly, but I wouldn't know how you would do that with KTuner. I'm surprised it's even looking for knock at low loads. As for which direction the sensitivity parameter goes, I would email KTuner support (https://ktuner.com/contact/) and ask.

Make sure you don't have a mechanical issue like a piston hitting the head / valves, straight cut gear rattling, loose motor mount, etc).

As David said, I strongly suspect the issue lies elsewhere and it's a false reading - either a mechanical issue with parts coming into contact, or plain old piston slap, which can be very noticeable on a cold engine with forged pistons as they have a much greater initial clearance to allow for their expansion.

If you did a full interference check for V2P, through the full range of camshaft timing assuming you didn't disable the VTEC, that should be eliminated and same for the big-end and mains clearances.

Something that can be overlooked is confirming the ECU's "TDC" actually lines up with the engine's physical TDC - the latter should have been confirmed during a dummy build, or at least during final cam' timing, but if not it can be done with a DTI or similar down the spark plug hole and marking the damper/pully/front cover. Then locking the ECU at zero advance and using a timing light.

If the ECU "TDC" is significantly advanced from the mechanical "TDC", it could go a long way to explaining some of your issues.

The engine builder did all of the hard work. only needed minimal decking and same with the head. He stated that the clearances are great and should not be an issue. My brother in-law reassembled the rest of the motor while i worked on the car. There is minimal room for us to do much at all. 97 K Swapped Integra. But i will take a look at the items you guys have stated.

Car does go in to dyno on Saturday morning. Going to have him figure out how much the knock is for real.

Thank you for the information.

Lots of great suggestions here already, so I'll simply say it's very unlikely the engine is detonating at idle.

Combustion is likely poor at idle from aggressive cams, but I wouldn't take all the timing out or run it real rich based on the knock monitor in an idle condition.

Does the knock persist at all RPM, or just idle. Have you tried raising idle speed to 1000 RPM for example to see if it goes away?

So after some adjusting and checking of many things, we do for sure have an injector that is putting in more fuel then the rest. I moved it from cyl 3 to cyl 4 and cyl 4 started running rich as can be. All of the things i was trying with the tune and checking of other items i did before going to the dyno. The guy there told me i was doing everything correctly with the tune and that. But we could not get cyl 3 to stop being rich. He suspected an injector issue. So now i have a new set of injectors on its way. Working with him and asking questions to help me understand i was doing everything correctly made me feel better about making adjustments as its needed. So once i get the injectors in, and a fresh set of plugs, things should be good to go.

His words, The injector is causing it to misfire and causing the system to detect it as an ign knock. He tried to removing timing and add timing, no difference at all. i was little surprised that the timing of 2 degrees lowered my power like it did. took a little out and same thing. he stated that its right where it needs to be.

Once the injectors come in, we will swap them out and do a test and tune day at the track. Logs will be looked at and we will see if the knocking and any misfires happens. Should not, but you never know.

Thank you for the help everyone.

oh, we went through 2 sets of plugs just to make sure we could get a good healthy base from the dyno. Spent less the 3 hours on it. he liked how it was over all even with the misfire happening. 45 minutes of that time we went through making sure all was good with the coils and wiring. looked at the plugs many times. best run was rd to last with the last set of fresh plugs. just before playing with the timing a little.

Sounds good! Best of luck Mark.