Idle tip-in/throttle blip knock

[Clipdat]

Originally Posted by tomm.brz

usually if a oring is missing it just makes the loud pop on quick blips at any rpm, anyway if in doubt just have someone blip on ur car while you are in the front with bay opened, it s pretty obvious if a loud pop comes from the heads
i ve seen videos even with a small cloud of vaporized fuel fuming out of the injectors some years ago

Sounds like we need a video from @Nfsundrgrnd with the hood open. I'm not 100% convinced it's DI seals yet, but the knock sound and the low adv. multiplier are certainly concerning.

"quick blips at any rpm" - that's the weird thing about this is that I can rev from 1k to 2,500 or 3,000 over and over and no pop/clunk/knock/whatever. It only does it when it's at the resting ~650rpm idle. Even if I feather slightly to get over the resting idle and then do a throttle stab, no weird noise.

[Clipdat]

Originally Posted by fredzy

My 23 makes more or less this same sound doing the same thing. Piston rattle knock/clacky sound. Did it off the lot.

Maybe make a video as well and we can compare noises? I'll do one this weekend and datalogging if I have time.

[NoHaveMSG]

@tomm.brz can the poor transient ignition timings cause this type of running issue even without blowing a seal?

I guess it is possible that @Clipdat has a seal in the process of failing and not completely gone and is only producing the issue at higher engine loads. Just throwing idea's out there.

[DarkPira7e]

Curious if this has anything to do with the change made in the A01C / B01C map compared to A00C. There was a pretty strong change made in the transient ignition retard to address tip in knock.

[tomm.brz]

yes that s exactly the main change they did

From 2017 they changed it again and made it a lot more retarded, to the point that any restyling car has lagging throttle blips because of the huge retard

[tomm.brz]

Originally Posted by NoHaveMSG

@tomm.brz can the poor transient ignition timings cause this type of running issue even without blowing a seal?

I guess it is possible that @Clipdat has a seal in the process of failing and not completely gone and is only producing the issue at higher engine loads. Just throwing idea's out there.

i dont know, the lack of retard in old stock tune just brings out some pre-ignition/knock/detonation/misfire immediately after a strong blip, per se it s not a huge deal, engine is not going to destroy for this and ecu can correct instantly a bit and limit damage.. anyway while NA is basically not going to do any harm
but
happens to casually destroy the oring of DI injectors, people learnt this the hard way and Subaru/toyota too so then they issued the bulletin explaining why Orings failed and released the update of the tune

I have no idea if it can be possibile to damage the oring only lightly that loose the seal only at higher rpm, or if the sound of knocking can be heard in the cabin while driving but i d doubt it

[Nfsundrgrnd]

Originally Posted by tomm.brz

i dont know, the lack of retard in old stock tune just brings out some pre-ignition/knock/detonation/misfire immediately after a strong blip, per se it s not a huge deal, engine is not going to destroy for this and ecu can correct instantly a bit and limit damage.. anyway while NA is basically not going to do any harm
but
happens to casually destroy the oring of DI injectors, people learnt this the hard way and Subaru/toyota too so then they issued the bulletin explaining why Orings failed and released the update of the tune

I have no idea if it can be possibile to damage the oring only lightly that loose the seal only at higher rpm, or if the sound of knocking can be heard in the cabin while driving but i d doubt it

I could try to get a log tomorrow of casual and spirited driving to see if it's working well while under load. I would've expected more issues from a blown seal but maybe they're borderline bad. It's been doing this in my old and new shortblock.

[Ultramaroon]

I've never heard the sound of a failed DI seal but I've always assumed that once it pops, it burns quickly and would be heard constantly. Am I wrong?

[tomm.brz]

well it misfires and loose compression the more damaged the seal is so it could throw some codes too(like too lean or misfiring) together with harsh sound during acceleration and popping sound like this:

[Ultramaroon]

My google fu was weak. Thanks. Sounds exactly like the culprit here.


Guys, don't let this discourage you. It's a serious job but it doesn't involve tearing apart the engine.

[Clipdat]

I just looked at the video Tomm posted. I don't identify that as the exact same sound, or reproduced at the same time during the rev stab as what need for speed and I are experiencing. Close, but no cigar. Also, if you notice in the video, he's not letting the revs fall back to the resting idle before revving again, and it still makes the noise. Not the case for us. More investigation is needed.

And if it DOES turn out to be DI seals, the only way I'm doing this job in my driveway is if I fly you down and we do it together lol.

[Clipdat]

We need more open hood videos. It honestly sounds like it could be something belt tensioner related. Just an uneducated guess.

I mean I can rev it like crazy, from 1k to 4k or above. Zero popping/knocking or strange noises. Even let it fall from 4k to 3k and rev back to 4k over and over and over. Nothing.


Plus the fact that @fredzy's 23 does it is an interesting data point. Hopefully he can make a video for us when he has time.

[tomm.brz]

well the video of loud popping surely relates to OP's car

for you we wait a video of yours

[Nfsundrgrnd]

Originally Posted by tomm.brz

well the video of loud popping surely relates to OP's car

for you we wait a video of yours

Actually I agree with ClipDat, the only issue I have is with it resting at Idle, no other issues anywhere else in the RPMs. It sounds similar but I've never been able to replicate the noise other than at resting Idle. Gonna get a log in a bit of spirited driving for more data. I'd assume it would be noticeable in those logs if the injector is acting up.