ANY UPDATES ON THE ENGINE NOISE!

Every gen 4 we tested and two that go by in our neighborhood sound like ours.

 

go spend 100k on a rivian, it will be the worst financial decision you can make, but sounds like you'll be happier

 

I don't think they did, that would be crazy for them to do that. I remote started mine in the driveway and could hear it switch modes. Sounded exactly like my 3rd gens, just a little quieter.

 

The self cleaning injector mode was a different feature from the traditional d4s. The engine still had port and direct injection and cycles back and forth as needed but the “injector cleaning mode” I believe was discontinued just what I heard no idea the truth of it to be honest though.

 

Well, when it switches to port injection it in theory is cleaning the back of the intake valves. They may have stopped calling it that procedure to avoid confusion.

 

The Car Care Nut on YT says the 4th gen Tacoma has the enhanced D4S engine: 4 Direct Injection ports and 4 Port Injection.
https://youtu.be/qX6gUJrlyW4?t=645

 

Test Driven Garage on YT also says the 4th gen Tacoma has 4 DI and 4 PI:

https://youtu.be/HuNe6OD9Pw0?t=41

 

Just to clarify for others in this thread. 11:37 of the video he mentions “diesel mode” ie the cleaning mode is no longer a thing.

 

I may have gotten lucky then. I have the TRD OR and I haven't noticed anything concerning. My hood definitely doesn't flop around at all. Maybe my assembly lineman wasn't hungover when they assembled mine. Lol. I didn't know it was a common problem so I was trying to think of anything OP could have been hearing that's different than an old Tacoma. Glad yours seems to have quieted down some.

 

This is the best description of this noise I have come across. Mine does it cold or hot most of the time. Since the power is right there it occurs only for a split second or two. Then, if it is still present, it is hard to hear over the revving of the motor. I'm interested in what other say about this. My dealer service manager acknowledged complaints regarding this but did not disclose much else.

I just bought and used the Carista to change the engine sound enhancement setting at it worked very well. Took all of 10 minutes.

 

For anyone coming here interested in engine noise and what is being talked about here are some videos with sound.

https://photos.app.goo.gl/yBdhAqKuxkWuCgtL9

Hood open cold start, open after idle, hood closed cold start, and most importantly in cab.

In cab has no AC running to try to hear the idle better, then some revs for context.

 

.5 stroke this thing doesn't even stroke fully

 

I wanted to give my update here after several months. The Carista did help but I have been wondering exactly how much now. The warmer the temp definitively enhances the noise which is the same clattering at lower rpm's under modest or hard acceleration describes by another member. On a cold engine I never hear it. The colder it is outside the less i hear it for sure. There is something here to do with temperature for sure. It is most likely to be louder on warmer days with the engine warmed up well. Regular vs high octane makes a difference too. Every truck i ever had ran better on premium than on regular. That includes every one of my previous gen tacomas as well. In the case of the noise and the octane, it may be as simple as the noise being lessened by a little more smoothness and responsiveness with the high octane fuel. I'm still interested if anyone really got to the bottom of this noise in particular.

 

The technical info from TIS about this engine says that the engine will decide on using port OR direct injection at low throttle, direct AND port at moderate throttle, and direct only at high throttle. I think this is what's happening, and why it only appears in that 2500-3500 range with moderate throttle. This would explain why it's worse in Eco than normal, and almost absent in sport.

 

Appreciate the feedback. I have to look into switching modes further.

 

I'm not a carologist, so consider the source. But I'm at least as smart as the bottom 50% of youtube mechanics.

I set up a Scangauge to look at the engine timing. There's no pretty graphs, and just a nearly worthless on person anecdote but here's what I saw:

• Fuel octane has a noticeable effect on ignition timing (as expected). With 91 octane, the lowest I've seen normally is -5, and the average on highway is 10-20 at steady state. 87 is in the -20s to 5 normally.
• The chatter happens regardless of octane. If it was knock, I would expect to hear less of it with 91 than 87. I do not.
• The noise happens less if at all at WOT and higher RPMS. If it was knock, I would expect this to make it worse not better.
• When this chatter happens, there's no reduction in ignition timing. In fact, if I keep it right around 3000 rpm with throttle moderate to maximize the chatter, ignition timing advances, not retards especially with premium fuel. This is another clue to me it is not knock. Mashing on the throttle shows the ignition timing going well into the 30s absent any chatter.

So:
To my untrained mind, this is not knock because if it was, the ignition timing would retard instantly, it would get worse with throttle, and would also reduce with premium. None of this happens.

The other option is there's some sort of resonance with a metal part on the engine that happens in this RPM range. I can't find anything loose enough to rattle, like a metal cover or something.

 

There's a graph about three quarters of the way down on https://www.toyota-club.net/files/faq/21-09-20_faq_t24-engine_en.htm that indicates roughly which injection system the engine uses and when. I get the impression that it switches back and forth at lower loads and engine speeds. I've noticed that mine tends to "rattle" at loaded idle but then quiets down when I apply a touch of throttle, like when I'm in gear and set off down the driveway.

I'm pretty sure the "rattle" is the direct injectors. One of these days I might climb up there and put my mechanic's stethoscope on things to see if I can figure out where it's coming from. The first thing that popped into my head when I heard it was timing chain slop, but it's too high pitched and it goes away much too quickly — that is, too quickly for it to be oil-pressure-controlled-tensioner related — when throttle is applied. At least if my ears are tuned right; I'm mostly used to the sound from the auxiliary timing chain made on older L4 VAG engines or the sound more modern L4 BMW engines make when their oil-controlled tensioners go sideways.

 

It almost sounds like car diesel injection in other countries . Hopefully its not pinging trying to get better MPG for tax credits

 

Sounds completely normal to me for a modern DI engine.

 

I like the grunty weird diesel sound of this engine. Zero complaints. Let her speak. I don’t even want the sound deadening. This will be the last ICE toyota truck. Enjoy her clicks, clacks and grunts.