3.4L w/ ETCS TB cleaning

So in an effort to help with idle issues I researched for a while on here and came across some good threads with lots of information. Ordered the gaskets to replace when I took off the TB.

Took a week or two to finally get the weather to break on the weekend to do this but here it is. Also found out that the ETCS does not have the separate bolt on IAC ('02 and lower). Decided to take pics for myself and any others who want to look upon them.

I will not go through how to remove as that's pretty much covered, also I had the battery disconnected the whole time (gotta reset the dam radio now, grr) as I hadn't done that before when I attempted to clean the TB back in October. Without further ado here are some pics of my '04 TB w/ ETCS:

with coolant lines still attached and electrics unplugged



such a small thing for one grand



internal (plenum) side



the TPS and ECM motor control (motor is in place of what would be the IAC)



decided to take out these four screws and see



and boy did I see. 10 years worth to be exact



the holes from inside the top of TB. from what I can see with the plate closed these holes are barely uncovered, sort of an IAC maybe?



so cleaned up everything real good and used a toothbrush to clean the holes out, along with a paperclip for the baked on carbon



another with the holes cleaned out



I decided not to pull the TPS or *@#$ with taking off the inside cover so as to not screw up anything with the little motor. When you turn the plate you can feel the resistance and gear turning; and not knowing what was involved I didn't want to risk $1,000 to find out

Seeing as the cover is on the top it may make cleaning in the future easier now that I know.

Results:

hooked everything back up, started her up to a tune of 1750 rpm for about 15 seconds, then down to 1250, then hovered around 1100 for a minute. When OOT was reached you could hear it rev down and watched it go down to 750 and stay there for a few minutes. turned on defrost and it hit 800, turned off and back to 750.

My assumption was when I "attempted" to clean the outside of the TB inlet back in October I may have pushed extra carbon up into the small holes therefore clogging them more. I have only driven it one time (yesterday to get home) but it was highway at 60-70 mph but felt good.

I will be hyper-miling as best I can for the next 90 days as my new insurance has a program for an OBD2 device to track driving habits, and hell, I like saving money

 

Can't figure out why no one commented on this write up? Nicely done, I found it in a search for servicing IAC before finding out mine doesn't have one.. Thanks, I'll be using your write up to service my ETCS Throttle Body.

 

glad at least someone looked at it

I still have the idle issues so I have some testing to do.

 

ttt for educational purposes

 

what sort of idle issues do you still have and have you made any progress of thoughts on what it might be?

 

I kind of live with it for now. I've changed plugs/wires and such but it may be wear and tear on the butterfly causing gaps. it only started happening after I cleaned it the first time two years ago.

I'll get a high idle (even after warmed up) around 11-1200 or a low idle sometimes down to 300 (kinda feels like a diesel )

haven't changed any vacuum hoses yet or replaced any gaskets (no leaks from heads so haven't bothered to tear anything apart)

heck it could be a faulty TPS but it only happens for idle. once moving there are no issues so...

 

might want to carefully look over the intake ducting for splits, cracks, or something leaking when its had time to cool down like rubber boot seals, maybe even the maf flange seal to air box.

might even be a timing belt passed its time

 

I replaced the stock box/intake tube this past year and did the Timing Belt/WP at 88k

 

mine has a random rough idle that goes away if you rev the engine a few times but cant figure out the cause. it can run smooth for days, then out of the blue, rough idle in gear, smooths out if in neutral, goes away if you rev it a fee times. otherwise it runs fine and has no power issues and gets 18mpg average

never has a CEL code or anything but I already cleaned MAF and TB and replaced the plugs trying to solve this. im going to try new plug wires next just for the hell of it..

 

Did this today. Feels like a brand new truck. Appreciate that you have this posted Frizzman. Thank you.

 

I too have done this thorough tb cleaning (this is a great write up-thank you) along with new plugs , wires, and tb/wp job. Runs like a new truck. If after cleaning you still have high/low idle, I agree that there is likely a vac. leak. It might be intermittent like a "flap" type leak that only opens under some conditions. Check your air intake plumbing downstream of the MAF for any small leak like that .

 

Great write up! I plan on cleaning my TB, this weekend. My gas mileage has gone down to 11-13 mpg from 16-17, so I'm staring the deep dive from the top. I just replaced SPs/wires and oil change, so I am down to TB and Air filter cleaning. I've cleaned the TB before if shoving a shop rag into the TB intake and spraying with Carb cleaner counts. Was concerned about gaskets and all that, now I see it's pretty straight forward.

Thanks again.

 

I cleaned the throttle body and intake, I only saw a small increase in fuel economy. I am thinking it is the coils at this point since I have changed out the spark plugs and wires. At 170K miles, seeing some wear around 2 of the igniter coils. Just orders new ones, hoping this helps more.

 

Yes, Great write up. However, the rectangle paperish gasket on top of the throttle body, where you removed the small 4 screws and cleaned the holes. Where can I find a gasket for replacement? Mine tore. I cannot find a part number of description of what it is.

 

Use the torn one as a template to cut a new one from gasket paper, or just use some fipg.
BTW, I replaced the 4 philips screws with Allen head screws from Lowes.

 

Doing my own research for this job, I found out the 6 holes that come out behind the throttle body plate are for the "Air Assist" system for the fuel injectors. Check out this thread I started on T4R.org: So, when somebody inadvertently smashes crud into those 6 holes, it's affecting the air assist to the injectors. It appears the throttle body on later models, 03 and 04, have a combination Drive by Wire and Cable Actuated throttle body. It's a kind of hybrid throttle body with an electronically controlled throttle plate with a mechanical cable actuated back-up. Looks like Toyota was in the process of switching over to full DBW throttle bodies but wanted a cable actuated back-up. Kind of interesting, right? The throttle plate has some type of set screw that doesn't allow the throttle plate to fully seat so the engine gets the air it needs at idle - at least that's the theory. The throttle plate will also make electronic adjustments like the situation when the AC turns on and the idle rpms increase.

Now, why do some people have a High Idle after doing a throttle body cleaning? It could be a situation that the throttle plate isn't closing as far as before the cleaning. It could also be a vacuum leak by the person forgetting to attach a vacuum hose. But, if the throttle body was cleaned carefully, all the vacuum hoses were reattached properly, and the hoses are intact, a person should have a normal idling engine after completing this job.

 

Isn’t it good practice to disconnect the battery when cleaning the throttle body?

 

I just watched @Timmah! ’s YT video last night. I know I’ve cleaned my Throttle body when I first bought it but never knew anything about an IAC (or wether my truck even has one). I most likely pushed all that garbage I cleaned out of the TB and into the IAC or those little holes that are the air assist to the injectors. I ended up buying an A/F sensor and an o2 sensor as well as a new MAF. Gonna clean out the TB again. I would be mind blown if I got my power back that I chalked up to an aging truck!

 

will you be doing a follow up YT vid for these types of throttle bodies? Id like it

eh, probably doesn’t matter but if you do, I didn’t-remember your truck will act and run oddly after til the ECU measures and adjusts the parameters-
Which may have you wondering if you did it right : !

 

There's a very good chance we will make a video for the newer throttle bodies.