Throttle Plate Spary Cleaning, Idle Air Bypass

[VijayW]

Throttle Plate Spray Cleaning, Idle Air Bypass

Hi All,

This LC99 UZJ100 with over 250k miles idles smoothly, and gas mileage is not bad either (14mpg average) but a few weeks ago, especially after a fast drive of about 50 miles, I noticed that the idle speed in D dropped to below 600rpm, which wasn't moving the vehicle when I released the brakes.

I inspected the throttle plate, and wiped it clean by hand, using SeaFoam DeepCreep (a multipurpose cleaner, lubricant type). In that process, I removed a decent amount of carbon deposits from the finger-reach area behind the throttle plate. This cleaning immediately increased the cold-idling speed (before engaging any gears) to about 1200rpm, and warm idling is about 800rpm. So, I figure more cleaning could help. I am not able to disassemble the throttle body, so I'm hoping to do a SeaFoam Spray treatment.

Please note that the SeaFoam spray is introduced thru’ the air intake, as opposed to the traditional SeaFoam engine treatment, which is introduced through vacuum lines, of which a lot of posts are found. I hope to do this cleaning over the weekend, and will report back. I have several questions in this regard:

1. SeaFoam instructions specify that while applying the spray the engine speed should be well above the factory idle speed so that the spray would enter thru the throttle plate opening, and not thru' the idle air bypass. But as my photos show, and as far I can see with eyes, I don't find an idle air bypass opening before the throttle plate in this engine (2UZ-FE). How come? Does this means that I don't need to rev up much while introducing the spray?

2. Should I desire to increase the idling speed while spraying, and if I have to do the project on my own, is it ok to pull on the throttle cable in the engine compartment?

3. I figure that after cleaning, the idle speed will increase again. To get the car to re-learn the idle speed, do I need to disconnect the battery cables for a while, before driving it around?

Thanks in advance.

 

[TXLX100]

If you are just interested in cleaning the throttle plate, I find it easier to simply unbolt the throttle body, pull it away from the intake a bit, and clean the backside that way. That and clean the mass air flow sensor. Disconnect the battery before all that.

Personally, I'm a leery of spraying a bunch of flammable cleaner down the intake with the engine running. If you go too fast, you can send a bunch of unburned fuel into the catalytic converters. If you are only trying to clean the throttle plate, maybe this method isn't needed. If you are going for a whole "intake cleaning" maybe it's a good thing. 14mpg isn't all that bad. I get around 12mpg on 87 octane.

 

[APKhaos]

Hand cleaning works perfectly well. You can rotate the throttle place to clean the back side, and the nasty patch that forms on the bottom of the intake bore on both sides of the throttle plate.
Hand cleaning gets everything shiny clean and also prevents this muck from being ingested by the engine.

 

[2001LC]

Additional methods of Fuel and Air Systems cleaning with 44K, Air filter, Deep Creep and Sea Foam.

Start by adding 44K to gas tank.
Finish disconnecting battery for 30 minutes this is very important to reset systems, and using MAF season cleaner.

Next: Spraying into "Throttle Body PCV vacuum port" will raise RPM, as will pulling on throttle cable to reach ~1,500 RPM.
Then turn engine off to let soak.


RR Air Box & MAF cleaning.


Clean Throttle Body Valve & Throat with Deep Creep and/or Sea Foam scrubbing with copper bristle (old gun bore cleaning brush) & tooth brushes.


Clean & Treat plastic air induction tube at mouth.

Button-up and now Spray Sea Foam in Throttle Body PCV port at ~ 1,500 RPM.


Put 44K in with 1/2 tank of gas for a medium strength mixture.

Deep Creep ( Deep Creep optional);

Remove engine cover then spray 1/4 can (about one minute) of Deep Creep Spray into Throttle Body PCV vacuum tube, soaking air intake system all the way out tail pipe - at ~1,500 RPM. Turn engine off, let Deep Creep soak into built-up deposits and seep, albeit by a small amount, down the cylinders walls down into crankcase and oil.

Next cleaned air induction tube/box, Air filter & MAF Meter with spray cleaner only.


Clean throttle body:

While soaking; Clean Throttle Body Valve & Throat, with Deep Creep spray I like lubricating around T-Body valve axle really liberally. I also use Sea Foam, but I'm sparing with spray around throttle valve's axle where it passes into walls of throat & gear box. A tooth brush along with copper bristle brush (old gun bore cleaning brush) works well.

Before buttoning-up place a drop oil on each side of axle of throttle valve (butterfly) just where axle enters throttle body and work in. Wipe throat & valve (butterfly) areas dry.

Now button-up, start engine and spray 1/4 of can of Deep Creep liberally into PCV vacuum tube. After short engine shut down for soaking again, drive 10 miles at high rpm, up-down hills, left-right around corners and hard braking too sloshing around 44K in the tank. Then spray a little more while at while RPM slightly raised just prior to each engine shut-down to soak.

>><< Road trip, to disperse the 44K & blow-out Sea Foam products throughout fuel, air & oiling systems. I didn't replace engine cover yet, so I can spray a little before each engine shut downs, repeat soak (spraying) until can empty.

oh-ya.
Ran great and sounded even better at 3,000 to 4,000 rpm (OD off) for 100 miles, hwy and mountain roads. Driving in higher power band will aid cleaning the fuel system and blows out the carbon.

Now drive normal until gas near empty.

Sea Foam spray blow-out:

Deep Creep was more soaking & lubricating, whereas Sea Foam is for blowout cleaning.

Spray 1/2 can of Sea Foam into T-Body PCV vacuum tube while at ~1,500 RPM, then shut down engine to soak 5 minutes.

Then start-up and spray last of Sea Foam in at ~1,500 RPM. Then drive at least 10 minutes at high RPM, even better hit the highway until gas tank empty of 44K mix.

Finish by disconnecting battery for 30 minutes this is very important to reset systems. Using MAF cleaner while battery disconnected on MAF sensor.

Now its time for oil and filter change.


Sea Foam pros & con: See So, your curious about Seafoam.

 

[SupraTuRD]

That "lake of seafoam" is scary... I'd be afraid of hydro-locking the engine with that much liquid.

 

[2001LC]

Hi All,***
*****

1. *** Does this means that I don't need to rev up much while introducing the spray?

2. ****is it ok to pull on the throttle cable in the engine compartment?

3. ****do I need to disconnect the battery cables for a while, before driving it around?

Thanks in advance.

1) I'd keep RPM up while spraying in your case, so sea foam doesn't follow back into air induction tube.
2) Sure just don't go crazy pulling on cable, housing or brackets.
3) No reason to unless you get a check engine light.

You have a cool idea here, If one could leave in place and air tight, then could be use periodically. Maybe a switch to release spray on demand, spray in a high octane boost.

That "lake of seafoam" is scary... I'd be afraid of hydro-locking the engine with that much liquid.

Had I seen picture before driving and blowing white smoke; Well, I may not have run at 4,000 plus RMP in low gear for 10 min. But actually not as much as pictures may make one think. Second pic is not following out , it's just been sprayed to soak on throttle valve. My bigger concern is with fouling spark plugs.

I' found that diagram ^^^ which show the vapor flow, not as much chance of getting liquid into cylinders as one would think.

 

[VijayW]

Thanks to all who commented very helpfully! Sorry that my post wasn't clear about what I am planning to do: I meant cleaning the throttle body with the spray version of SeaFoam which is introduced through the throttle plate. This is supposedly the same as the SeaFoam Engine Treatment with additional CO2 propellant.

Yesterday I drove this LC 99 to a friend in a rural area, so that sometime in the morning I can do this cleaning with no neighbors to complain about the smoke. In that drive of 284 miles of which 95% was highway from NJ to NH with no traffic backups, I spent only 15.17 gallons of gas (93 Oct); so I actually did 18.72 mpg on this trip. I will calculate the mpg for way back home after SeaFoam cleaning for comparison.

As suggested by many of you I will do more cleaning by hand (Deep Creep through the vacuum inlet, toothbrush cleaning etc), before the spray. The diagram showing the tubing is from the SeaFoam spray can; it's not my idea. It has been around 2 years. See the following YouTube video at 1min 30sec:
http://www.youtube.com/watch?v=Vqs8QWvssmg

It surely would be nice if you can do the spray while driving at highway speeds. Those who do the "water injection cleaning" supposedly have hookups and valves that they control while driving.

Will update Monday how the cleaning went. Thanks again!

 

[VijayW]

Sorry that it took me longer than promised to report back; there were no surprises. After a little more cleaning by hand, I used about 2/3 of the SeaFoam spray can. Re-starting the engine after spraying did not produce that much of the dreaded white smoke; only a tiny bit more than what you would see in a cold day.

Possible reasons for little smoke:
1. For the last 2 years, I have been using high octane gas with STP and/or DuraLube at almost every fill-up, so most of the internals were probably clean to begin with
2. I let the engine idle for a minute or so after the end of spraying - should have shut down right away
3. Half the smoke was coming thru' holes in the muffler (good way to see the holes)

I took time to patch most of the muffler holes; Holts Gun Gum paste, available on eBay, worked well.

On the way back, with more than 97% of the driving at highway speeds, 265 miles consumed 15.184 gallons of gas, yielding 17.45 mpg, somewhat less than on the way up (18.72 mpg), before the SeaFoam cleaning! The now-better-functioning muffler may be reducing the engine efficiency due to higher back pressure?, or it could have been the different weather that affected mpg.

My original reason for throttle cleaning, the under-600 rpm idling in D after hard-driving, returned today, so I will have to look at other things (haven't checked the Mass Airflow Sensors etc). I have 1/3 of SeaFoam spray can left, as well as have a bottle of the regular SeaFoam engine treatment (sucked-in thru' vacuum lines), so will try that again sometime as well.

Thanks again to everybody for sharing the experiences and ideas!

 

[2001LC]

****

My original reason for throttle cleaning, the under-600 rpm idling in D after hard-driving, returned today, ******

I assume you're speaking about vibration. Interesting yours is after hard drive, what is "hard drive"?

 

[VijayW]

I assume you're speaking about vibration. Interesting yours is after hard drive, what is "hard drive"?

Actually, there is no vibration; engine runs pretty smoothly. Even when the rpm drops below 600, it doesn't look like it's going to stall (never happened). It's just irritating that you have to press the gas pedal more than usual to get going. I usually drive rather defensively, accelerating at around half-throttle. My "hard-driving" is a session of driving more like an ordinary driver , accelerating rapidly, when I need to. Even then, the engine rpm very rarely gets close to 3000. It's kind of like the more I drive with gas pedal depressed much, the more the engine expects me to do the same even when pulling away from a stop.

 

[BillZ260]

I'd like to add I've recently run BG44 through my tank as the LAST step in these above, and it is what ended up dropping my idle back down to 600 RPM from 900 when I got the truck. The stuff works!