I knew I shouldn't have screwed with a perfectly operating throttle body, but when I finally cleaned my air filter, I thought, 'what the hey, let me see what my throttle body looked like'.



So, after seeing this, I scared myself into cleaning it with TB cleaner sprayed on a rag, just as described in the FAQ PDF we provide to our members.

Starts good, but now, my butterfly doesn't close all the way. I don't remember it having this issue when I first started cleaning it. Did I break a spring or something? Listen to this...



This condition is giving me all sorts of issues right around idle and during deceleration. I've been having sudden RPM drops on downhill grades, and it just seems that it likes to idle higher at all times...get this, except when in Park or Nuetral, in which it almost stalls...thats right, RPMs fall in N or P, and jump up in D.

Listen and watch...



Ok, what did I screw up? Do I need to start looking for another TB?

 

Sounds like . . . the Throttle Position Sensor or TP Motor is befuddled. Try the easy stuff first. Hard reboot and check the electrical connections on the TB. By moving the trottle plate mechanically you may have gone places the TPS and TPM may have never gone before.

 

To go where no man has gone before! Wow that is a task!

 

MrTexasDan asked if I locked the accelerator pedal down before manually opening it, which I did.

I'm going to disconnect both the TPS and pedal sensor, then do a hard reboot. Maybe even do the pedal press and open/close the TB.

I do have AutoEngenuity that can real time monitor the TPS and pedal sensor, right along side the RPM, and I did try looking at that yesterday (the computer screen shot in the video) but it measures in tenths of a percent, and at close, they both showed zero, even though it was open...just a smidge, which sounds mechanical to me. I'll try again, maybe I can see a difference.

 

Matt,
You may want to clean the connectors now that you have them removed. I am thinking you might have applied a little pressure on the connectors as you were working around them and that may have caused a communication problem with the TB.
Good Luck!

 

I just dont see how people have so many issues with tb cleaning. I do it so much without issue other than the occasional high idle after cleaning a really dirty 1. My proceedure is
with engine hot, key off, unbolt air intake spray cleaner into closed throttle, let sit a bit (10sec). Open the throttle blade with my fingers and hold open. Spray real good again and with my ex wifes tooth brush clean the bore and both sides of the blade. Spray to remove residue from cleaning. Repeat if needed but useally thats enough to have squeeky clean. Reinstall air intake tube and start immediatly and go drive to clean out the cleaner in the intake. Youre done, if you have a high idle do a hard reboot

 

Just below the throttle body in the intake manifold, on the firewall side, is a passage to the EGR valve. When I had my throttle body off (story for another day) I found that passage full of gunk, including hardened chunks of carbon.

Your throttle body sounded even dirtier than mine (and twice the mileage). Some of that gunk could have been dislodged after your cleaning and be partially clogging your EGR valve.

BRUTAL's method of spraying cleaner in the throttle body and letting it pool and sit a bit in the intake (rather than just wiping it with a cloth and solvent) should help dissolve those deposits. Easy potential fix to try.

 

I would like to throw this out. On my Rav4 I can remove the breather hose from the intake pipe to the TB and spray cleaner into the TB as it is running. Has anyone done that on our cars?

 

If the egr passage is blocked though you need to remove the egr assembly and manually clean the passage out

 

Nothing wrong with the TB not closing normal behavior, the position will be held by the DC motor. The IDS/WDS does have a TB reset for some model years, not sure if that could help, but there must be a reason this option exists. Am not so familiar with the NA engines, but I think I saw a vacuum sensor in your intake elbow, and these seem to be very sensitive to cleaners, and they could have an effect the engine behavior. Let’s hope if that was one it hasn’t been damaged, and would also do a full reset first as the behavior in the second part seems electrically.

 

Thanks guys, another hard reset this morning (while the TB was open) may have helped greatly. On my drive to work, I did not get any sudden RPM hikes or drops, even on a downhill...but that's just a one-way trip.

Tonight I still am going to do a little spraying directly onto and into the TB for a quick soak, hoping the ex-girlfriend's toothbrush is as effective as an ex-wife's, and see if I can get the minor fluctuations to pass. I am afraid I may have dislodged some of that carbon at the bottom, and it perhaps got sucked into a vacuum line which may not allow it to close fully...at all times.

I'll check those lines as well, maybe find something definitive.

If I want to check the EGR assembly (in being thorough), is that an easy removal?

 

To get the EGR valve off, I think you need to remove the throttle body first. If you go by the book, you should be prepared with new gaskets for the throttle body, egr valve and egr tube. Probably only worth doing if your problems continue after further cleaning.

 

you could but might set a ck eng llight since your inducing air befind the mass air flow sensor. Also your not gonna get the bottom of the tb blade clean. It only takes a few minutes to do the whole thing like i do. I also use bg product air induction cleaner with a high pressure wand that i slip in ontop of the tb and put the air intake back on and run the engine. It puts out avery fine mist that does a great job on not only the tb but the entire intake manifold and ports

 

I do agree Brutal that a good cleaning is paramount. What I was thinking of doing was to clean the TB with the spray and toothbrush as you indicated then drill a small hole in the intake tube just above the TB opening for the spray nozzle and spray as the engine is running. I just don’t know if this process will cause long term adverse affects other than throwing a code or two. And yes I would plug the hole when done.

 

Gus- Thats definitely an interesting 'out of the box' idea !

 

I think I can close the discussion, as I think the 2nd reboot has settled down the RPM increase on the gear shift lever selections, my highway speeds seem to reflect a few hundred RPM decrease, and I only noticed a couple times, during cruising and downhille, did the RPMs drop from around 1,300 to about 1,000 suddenly in an attempt to reduce speed to match the cruise setting. Basically, it felt like the throttle body shut entirely..then a second later, bumped itself back up to 1,300...it can't find a tach setting that it likes in between...at least for now.

I ran a bit of throttle body cleaner thru the body during engine idle. Similar to what brutal does with his air induction cleaning process, I put the little straw up into the throttle body, fit the air pipe over it, and squirted some of the cleaner in short, repetitive bursts under idle. The car 'inhaled' it, slowed down the RPMs, then returned shortly after. Repeated about a dozen times, and quit. Hoping to undo what I did previously to the intake system, if it was truly my fault for the odd behavior.

If something changes, I'll let you know.

Now, off to start a new thread...i've found myself a coolant leak.