2012 v6 at DCSB engine knocking @ 1500 rpm

Mine is also completely stock and I noticed the knock, not typical taco tick, within first 5,000 miles of owning my truck. I'm happy to hear there are those of you not experiencing this issue, but that doesn't mean it doesn't exist. And yes, so far so good with changing from 87 to 93 octane, but still frustrating that its what we are forced to deal with after shelling out so much hard earned cash.

 

Sorry that I have not been on here in a while. My truck was at the dealer from June 22nd through September 13th with the whole top end being replaced. Today, the same noise cropped up again. Adding to my suspicion that they did not know what the hell was causing the problem. So, they wasted 2 months of my time and theirs and over 13,500 dollars. Back in the shop on this coming Wednesday when both the mechanic and my service advisor will be there. I have secured an attorney and they have filed on Toyota as of a week ago. Toyota has 30 days to respond. I won't be saying anything else about the case until it is finished, but wanted to let you all know what is going on. Good luck to you all. I hope they have a fix for this soon.

 

2 1/2 months to replace the heads? There's more to this than they are telling you - getting a couple of heads with valves, cams, and assorted parts should not have taken that long. I wonder if the factory boys from San Ramon got hands on your engine parts and shipped them off to be analyzed and tested.

Good luck with getting it fixed, and moreover, good luck with the civil suit. Lemon law cases seem to take a few months to go through the process, but most settle out of court somewhere short of the law and motion calendar. You should be done with this by Februrary or March, I think. Unless Toyota delays and drags their feet. :-/

 

So I spent Thursday through today in Nevada. Temps went from a low of 36F at night, to highs in the mid-70's, but nothing hotter. Elevation was in the 3800-4300 foot range, gas was 91 Chevron the whole time.

Up and down and around and around, not a single ping the whole time. Coming back down 80, from Lovelock, we had a nasty headwind (35+) all the way into Reno. A couple of times when traffic thinned, I coasted down to about 30, let the A/T stay in 5th, and then nudged the throttle into that 1500 rpm "hot zone" - not a single misplaced noise. Ran like it should have. A little less power, given the altitude, but that was it. Fuel trims looked OK, AFR was normal.

The big difference is cylinder pressures. Even if the ECU wants to run on the lean side of things, the overall cylinder pressure is going to be lower since there is less air (by mass) to suck into a cylinder, and less fuel is metered in. Lower pressure means less chance of ping or detonation.

The other thing is that Toyota allegedly acknowledges there is an issue. If there is a fix in the works, and if that fix has any impact on engine management, I would guess it has to go through some sort of regulatory (government bullshit) review (EPA and/or CARB). I suppose that could take forever and a day.

Back in the Bay Area this afternoon, the temperature was pretty cool - upper 60's/low 70's is what I was seeing. Same gas (91 Chevron), sitting about 100-200 feet above sea level. *PING PING PING PING PING PING* in the 'hot zone' RPM range. *Shrug*

Oh, just for the doubter previously, when the problem started in May of this year, the truck was bone stock, and had a Leer shell on the back (150lbs). That was when the ping started. Today, it has the shell, a slight lift (1-1.5") and the factory wheels and tires, along with an Aluminess front bumper. If you want to do the figuring on the weight, that's about 250 extra pounds on/in the truck. The truck has a payload of roughly 1000 lbs. So if 1/4 of the rated payload is going to make the engine lug & ping under normal use conditions, Toyota is a bunch of knards.

By comparison the V6 '04 had an ARB+WARN M8K up front, FROR on the rear, BudBuilt skids, 2" lift and 235/85/16's on factory alloys. Plus my HiLift and some other "junk in the trunk". Never pinged on 87. Rated cylinder pressure on the 5VZFE is 178+ psi vs 189+ on the 1GR.

 

I too have the cold engine knock on my 2013 DCLB 4x4. I notice it during the warm up phase with ambient below 65F. I have 4500 miles on mine now. I've been researching on here lately to see if others have complained. Now that I have verified I'm not the only one I'm going to take mine in to get it on record.

I know that my 2006 that I traded in exhibited none of these noises. That engine did not have the EGR and air injection system.

If they cannot give me a reasonable explanation then for the $50 I will install the iridium plugs from the 4Runner and FJ 1GR-FE into my engine and evaluate it. I followed the break in schedule and also did a an oil change at 2500 miles using factory oil filter. Since purchase I run 93 octane premium fuel available at the local BP stations in town.

 

How about the identical engines that don't knock what is the difference? I live in the mountains and used to drive to sea level Portland every day. Don't doubt you have a noise but why do some knock and others don't. Same mapping same engine. Along with a knock sensor they also have an altitude sensor barometer sensor if you like.

 

That's a fine question, and one I cannot answer. I did notice one thing on the barometric pressure readout via the ScanGaugeII, that I don't understand. It's inferring (there is no direct sensor, as far as I can tell) a pressure of 14.4 psi at sea level, sometimes it will go to 14.6 (when I was passing through Sacramento). 14.4 psi is about 29.4 inches of mercury. I'll cross-check that with the local airport barometric reading this morning (currently showing 29.9, which should work out to a bit over 14.7 psi).

Perhaps the MAF is reporting less air flow than reality (not sure how intake tract dynamics impact this, though). That would cause the motor to be lean, and that would cause problems. At altitude the problem would be less likely to crop up, even with a questionable MAF due to lower cylinder pressures.

However, I did test the MAF per the FSM procedure (take a reading with engine off, should be 0.72 g/s or less) and it tested OK. And I would think a MAF would be the first thing Toyota (engineers, at least) would consider.

ETA - 1015.7mb at the airport this morning. That works out to 14.7x PSI. At idle, inferred PSI varied (this morning) from 14.4 to 14.6. Throttle open it would tend towards the 14.4, throttle closed it would tend to the 14.6. Prior to my jaunt in Nevada, PSI would always sit rock solid at 14.4. Perhaps bouncing around on the roads moved something around. (FWIW the MAF was cleaned about 3 weeks ago). If dirty, it should show lower PSI, not higher.

 

Just thinking out loud here. If one or both of the cams was off by a tooth would the engine even run? That may be a stupid question, I would think there would be some kind of indication if that was the case.

All these engines come from the Alabama plant, wondering if the serial numbers of engines with the issue are close to each other. That could indicate a bad batch of parts or something.

If high octane doesn't fix the problem, there HAS to be something else going on to cause the cylinder pressures/temps to be high enough to result in pre-ignition, something that the management system isn't catching.

 

I'm almost at 30k miles which means spark plug change. I'll pull them out to see what they look like with all the pinging, knocking and marble sounds coming from the engine

 

I pulled mine about 2500 miles after the problem started. All looked normal, but showed evidence of running lean. No metallic flakes fused to ceramic insulators, but the burn pattern was leaving the insulators too white for my liking. Oh, and the typical oily residue on #6 plug's threads. Which, from what I read here and other forums (4Runner, FJ) that's entirely typical for cylinder #6.

 

I've seen timing belts be off 1 tooth on the 5VZ-FE and the engine runs like garbage. No power, very rough, lots of misfires - basically there is no mistaking a timing belt or chain being off by a tooth.

I'll pull my engine serial # from the block and post it up later. Odds are, with this problem impacting some '08 and '09 trucks, but mostly '10 and later, engine serial #'s will be very spread apart.

We're all scratching heads. I guess Toyota is, too. At this rate, if they would spot me a loaner and a promise to replace the motor, I would lend them my truck for a few months to figure it out.

I wonder if there is some simple variation in the casting process that causes the combustion chamber to vary just enough to screw some folks and not others. Molds wear out over time and get replaced. In that case, they could have a few thousand engines from each molding cutover that have the problem.

Also, I THINK one other plant in the US makes the 1GR-FE (TN?), but don't quote me on that. The first digit of the engine # is the plant 'code'. So if someone pops in with a different 1st number, we'll know.

 

If the cam timing was off it would run for shit no doubt about it and throw codes. Toyota is very good about catching productions problems and I doubt some thing like that would get past them. That also would point to every engine from that plant having issues not just a few. I don't think the engines are actually built from scratch in the states just assembled.

 

You're saying they are good about catching problems like weak leaf springs, noisy blower motors, and pinging engines?

 

I believe the parts are cast in the United States by another Toyota-owned entity - Bodine Aluminum:

http://www.toyota.com/about/our_business/engineering_and_manufacturing/bodine/index.html

http://www.trybodinealuminum.com/

Whether the castings are the problem remains to be seen. That does not mean other plants don't make the 1GR-FE, but at least some of them are sourced in the U.S.

 

Or clunking driveshafts, poorly shifting A750's, insufficient engine mounts and lousy exhaust manifolds?

 

That is a drop in the bucket compared to the big 3. Weak springs? That is just what the American public wanted a soft ride notice that Canadian trucks have 4 leaves. Blower motors guess you have never heard GM's Pinging engines mine doesn't. Try a search the hot bed of pinging seems to be TW not sure why that is but that's where all the hits are. In the not too distant past Toyota parts had to be ordered by production date due to changes during production. Do you know GM frames are as bad if not worse then Toyota's? Ever heard of some one's Silverado having an new frame put under it? Springs the Chevys drive the springs through the beds when the hangers rust out and break off. If you think the Tacoma is such a piece of junk why did you buy one?

 

Castings shouldn't be a big deal -- they are then machined and the cylinders are sleeved.

I'm thinking more like an EGR sticking open or malfunctioning and creating higher cylinder temps, something in the management system that is not working right and not caught by the computer as an error.

 

Because my last Tacoma *wasn't* a piece of junk. And the one before that also wasn't a piece of junk. And my '92 wasn't a piece of junk. And my old man's '98 4Runner and my wife's '04 Matrix are also not pieces of junk.

But these 2nd gens seem to have an awfully long laundry list of issues, even 8 years in to the manufacturing of the same basic design. First year or two, I'll cut them some slack - you always miss bugs with the first release, whether it's cars, trucks or software. But 8 years later, and they still haven't figured out this shit, while other issues are starting to crop up?

Cry me a goddamn river about "Toyota quality".

 

There is no EGR (in the typical sense of an EGR valve) on the 1GR-FE. EGR is handled by VVT-i and pre-programmed valve timing overlap, to keep more post-combustion gas in the cylinder under the necessary conditions, usually cruise w/ light throttle application. That's the set of conditions under which an engine will tend to make the most NOx, and so the time when combustion chamber temps and pressures need to be lowered by the retention of post-combustion gas.

It's probably a combination of VVT-i timing, driving style, fuel used, engine condition and spark advance. There are any number of ways to solve the problem, but you're far more restricted in how you can resolve the problem and keep the Emissions Overlords happy. Richer mixture? Won't fly. Drop timing? That would require EGR changes, and won't fly. Decrease valve overlap? HC emissions would probably go up under cruise conditions, but NOx might decrease.

Oh well. It's possible that for those running Iridiums, those plugs are removing just enough extra heat from the cylinder to prevent detonation. Though given the size of the center electrode, I would think the copper plugs would be better at that.

 

Your post is very difficult to read.

First, I never implied the Tacoma is junk. I was trying to make the point that Toyota is not that great at fixing known issues.

The 4 leaf springs are not only found in Canada, btw.

There is a small list of known issues. Toyota has gone as far as creating TSBs and repairing a few of the issues at the dealership, but has not bothered fixing the trucks coming off of the manufacturing line.

The 4runners have the " bump from behind" TSB, but what about the Tacos?

Same symptom, no TSB AFAIK.


No, I have never heard of Silverado frame issues. I have owned several Silverados, have friends that work at GM dealerships, and even own their own shops and have never heard of springs going through the bed...

I was not comparing Toyota quality to other manufacturers..it is just really confusing to me that after 9 years of building these trucks that they still have some of the same annoying issues.


Don't be such a drama queen