NEW!!! Service Bulletin for Engine Knocking at Startup T-SB 0012-10

We had a mild temperature rain event the evening prior to the latest morning shake 'n start episode. Skies cleared and temperatures dropped off pretty quickly after midnight. Near perfect conditions for moisture condensation.

 

Maybe HEET dispels water in fuel?

 

That is what it is suppose to do (in the tank and lines), but wouldn't think that it would decrease the possibility of condensation in the IM. But possible.

 

That's why I'm thinking running the car in Normal instead of ECO may evaporate any excess condensation.

 

Could be the higher engine temps help to evaporate more of the water...

 

Yep, in the olden days it was a bad thermostat that would keep the condensation from evaporating 'cause it wouldn't get up to temperature. Ever take an oil filler cap off of an old beetle and see the milkshake on it?

 

Nope. I did see something like that in the radiator of my 99 outback when the head-gasket blew though.

 

Well, that's a Subaru, so that's normal.

 

I guess... I bought it with I think 56K miles thinking it was going to be invincible and two weeks later the head-gasket goes. Was I steamed.

 

You bring up milk shake in radiator.

Yes, I remember it well in my 1977 Chevy Monza with the Vega engine, blown head gasket.
That was normal for my car. =)

Gravedigger, are you saying the bad head gasket you show in the picture is the cause of the knocking??

I find that hard to believe because it happens on new off the lot cars.

Please clarify what you fixed is related to the knocking of the car or just the blown head gasket oil in radiator problem.

Thanks.

 

Well guys guess what! I had the intake manifold replaced a year or 2 ago and guess what happened.. First time temps dipped to below freezing, start car today, and knocking so violent it set off check engine light. So frustrated because obviously the repair didn't fix the issue... As this was supposed to be fixed before, I assume the dealership should handle this free of charge and not expect me to pay check engine light fee, etc?

 

They "should". Make sure it gets writen up again. Perhaps they will look into a better solution.

 

The original times I got the knock it was quick and more noise than violent knocks and it never tripped the check engine light. How many miles do you have?

For me the temporary, band aid fix for the winter knocking, will be high 93 octane fuel and removing moisture from the gas tank, until they find the real solution. I'm watching my morning starts like a hawk.

It was in the low 20's this morning and the car started quick and smooth.

 

Do you feel the 93 octane was the solution? I would be willing to try this (whatever it takes to stop the knock!). I moved the car a short distance the day before to a different parking spot, should have known better.

A few questions for you:

1) Are there any concerns of switching back to 87 in the spring time after using 93 octane all winter and the engine became "used to" 93 octane?

2) What would be the reasoning behind the 93 octane "preventing" the knock from occurring again?

 

To answer your original question, I have 35k miles. I was at 25k when the original IM was replaced, but not sure it was with the new ..54 IM part or not.

 

It would be great if you could try my suggestion. You could support or disprove my experience.

I have switched back and forth from spring octane and winter grade since winter 2011.
I usually try to mix it up when I switch back to spring time. I have an 80 mile daily commute so my fuel does not last in the tank more than a week. So mix it up to get back to spring grades to 87 octane.

Give it a tank or two and I hope you notice a smoother start up, so report back.
Please also run a Heet treatment to help lower the moisture level in the tank.

NOTE: If your wife drives the car, don't tell her you did it and wait to see if she notices anything different.

I do not have proof why this helps me.
Only that condensation/moisture has something to do with it from what I read here.
So this is my attempt to remove the H2O from the issue. IMHO

Thanks.

 

I thought the cause of the problem was moisture in the intake manifold (where the air for combustion comes from) rather than moisture in the fuel supply.

 

For what it is worth.

Having reported experiencing this a few times, I did get the engine mount T-SB performed by my Dealership. Reports that the Intake Mod has yet been successful correcting the issue, plus the need to duplicate in their presence has dissuaded my decision to further seek this remedy. I continue to power up as normal except I pump the accelerator once before the ICE engages, a trick learned before the T-SBs from another members post that works...when you remember to do it. Just need to follow a revised prestart checklist.

Will this problem ever be fixed...I doubt it. Even if Toyota knows the fix, my guess is that since no major mechanical failures have occurred, and that correcting this design flaw would likely be expensive, they are going to just continue to throw band-aids at it only when it throws a code (CEL) within the time frame of Warranty. The brakes still suck when slowing to a stop on rough roads...(acceleration)...and the software didn't fix that either.

Right or wrong, I have just learned to live with this too. It is embarrassing when it happens, but it is not a safety issue...and nothing breaks...so far.

This my take...YMMV.

 

Thanks for your input! Just so I understand this clearly.. how do you handle this when the ICE starts up the same time as the battery when you press the Start button in cold weather? Do you pump the gas a few times before pressing Start? Or do you press start and immediately pump accelerator a few times while being in park?

 

Pumping the gas pedal without the ICE running will do nothing to the throttle from what I was told. It may start the ICE, but it wont "prime" the ICE or move the throttle or other controls unless the ICE is starting up. Or something like that....