Disclaimer: "Please use caution and seek professional assistance when necessary. ColoradoFans.com, myself and all associated members are not responsible for any damages, injuries or other harm which may occur with this modification. This post does not reflect the views of ColoradoFans.com and it's ownership." Before attempting this modification, it is advised to verify your Colorado or Canyon service manual or a certified mechanic, as not all GMT 355's are the same!
A CFans Members Mod Projects/How-To by Cpnbnanamn
Throttle Body Cleaning
Skill Level: Moderate to Easy
Time Required: An hour to an hour and a half (to do a good job)
Model: Colorado ZQ8 LS
small flat blade screwdriver
3/8" drive ratchet (1/4" works too)
Old toothbrush or small medium bristle nylon brush
5" extension for 3/8 or 1/4 drive socket
3" extension for 3/8 or 1/4 drive socket
1 can Throttle Body Cleaner
1 Can Seafoam (Available at any local auto parts store)
1 Can Seafoam Deep Creep (optional)
3 ft tubing to fit funnel
Ok all.. This is relatively easy. Trust me, I was apprehensive about taking apart such an important part of my engine too, but this turned out to be really simple, and you'll save yourself $200+ in maintenance costs at a local mech or stealership. I was getting P0506 codes, and I'm not 100% sure it didn't cause my MAP sensor to flake out. That little piece cost me $60 from the parts store. (OEM was just over $100)
First thing I decided to do was give my engine a good dose of Seafoam liquid to help clean out the combustion chamber. My truck has 78K on it, and was running like crap. Simple enough, I just used a piece of vinyl tubing snaked through my air intake, right up to the TB.
Be sure to follow the directions on the bottle carefully. DO NOT pour this stuff into an engine that is NOT running. You CAN and WILL cause hydrolock (the engine will not be able to compress the liquid) and you WILL end up blowing your engine!!!!
It's also worth noting that you will want to make absolutely sure your exhaust is WELL ventilated. I had my truck sitting half out of the garage for this very reason. Begin to SLOWLY pour the liquid into the funnel, (Come on guys, you remember your days doing Beer Bongs... you know how). You'll notice that your engine will REALLY start to chug. Once you get about 1/3 of the can into the TB, shut off the engine, and remove the funnel and tubing. Let this sit for about 5 minutes. When time is up, restart the engine. Be positive that everyone and anything you don't mind getting all nasty is away from the exhaust on the truck. You see a puff of some nasty crap come out of the exhaust along with a lot of smoke. Don't panic. This is normal, and will subside in a couple minutes.
So far so good, right?? Great!! You've just completed phase I!
Next, it's time to get ready to clean the TB itself.
First, remove your positive lead from your battery. I did, as a means to help prevent several possible issues from coming up.
Then remove the MAF sensor. It requires a 5.5mm socket to remove both of the bolts attaching it to the intake.
Next remove your air intake assembly:
(Thanks to Canyon08Z71 for digging up this pic. I snagged it from his post in another thread, because my truck no longer has the stock intake. Hope you don't mind, dude..)
8mm (2- hose clamps - loosen one at the airbox connection - loosen one at the throttle body connection) and 10mm(2 bolts - holds resonator to engine)
This is mine:
You will also have to remove 2 tubes that connect your engine to your intake.
This will expose your Throttle Body:
Next, using a 10mm socket and either a long extension, or by connecting a couple short ones, remove the 4 bolts that surround the throat of the TB.
I should also note here that I opted to wait until I got the TB off the engine to remove the fuel line and electrical connection. It made it easier to get to them.
Now the electrical connection was a little tricky. Use extra care in removal so not to destroy the retaining clip or keeper. I used a screw driver to slide the keeper back so that the retaining clip could be depressed.
Then it's time to remove the fuel line. Now this one was also a little tricky at first, but once I figured it out, EASY! There is a retaining clip that passes completely through the nozzle that connects to the TB. It DOES NOT come out, but will slide enough to one side or the other to allow for the fuel line to be removed easily. I just used my thumbnail to push on it, and the line came right off.
Once this is all done, you should have the TB off in your hand!! Mine was NASTY!!! No WONDER it had been running so rough!!!
Time to get out the cleaning supplies!
Now get to work cleaning your TB. Note that at the top of the TB on the side that mates with the intake manifold, there is a little hole. That hole is connected to the fuel line, and is where gas is injected and mixed with air. It'd be a good idea to make sure that the brass nozzle and path to that hole, including the hole are cleaned out. (If you look closely at the pic below, you'll see the brass fuel nozzle, then directly below my index finger is the aforementioned hole)
Now, I used the Throttle Body cleaner , an old toothbrush and shop rags for the chief amount of cleaning, and then used the Deep Creep afterwards inside the throat because of the oils that Creep has in it for lubrication. I left a thin film of it on the butterfly and throat. I'm hoping that will retard buildup of carbon and crap on my TB.
Also keep in mind, that you'll want to take your time and make sure you clean this thoroughly. Any little bit of carbon or crap left in the throat will cause issue, possibly not allowing your TB butterfly to close properly, allow air leakage, and therefore defeating the purpose of this cleaning. DO NOT use ANY sharp objects in the throat to clean out buildup! Your result should look similar to this:
Also notice that there is a lip on the back of the throat where the butterfly rests in the closed position. Make sure you get that clean too.
After this, since I tend to be a little anal-retentive about stuff like this, I cleaned the mating surface of the intake and removed and cleaned the O-ring in the groove and the groove itself.
Keep one thing in mind when putting your O-ring back. It IS a little bigger than the groove, but it will go. You will just have to work it in.
At this point you're over the hump, so now it's time to just reverse the process. Don't forget to reconnect your fuel line, and electrical connection to the TB, making sure that they are firmly seated, as well as making sure to re-install your MAF and re-seat the electrical connection to that as well. Re-install your air intake system, and VIOLA!! Completed.
This process made my truck run like NEW and helped clear out the OBD codes I had been getting regarding idle. I hope this helps out someone.
My sincerest apologies for the inconvenience of not having the pics working on this thread! I recently decided to stop hosting my own website, and that's where these pics were being served from. I've moved all of them up to Photobucket, and this shouldn't be an issue anymore. I'm REALLY HAPPY to see that this writeup has helped so many people take care of their own trucks!! Hopefully, it'll continue to do that, and if I can help anyone out with this at all, please just let me know!
OK, I've been getting this question a lot lately, "Can I take off the intake and just pour the Seafoam into the TB?"
NO. You HAVE to have the engine running to pour Seafoam into the TB. If you remove the intake assembly, you will take the MAF sensor out of line, and the engine will start running VERY rough, and as soon as you pour the Seafoam in, the engine will probably stall, and throw codes.
"Can I use the brake crankcase tube or brake vacuum line?"
Brake Vacuum line? Sure why not. There's always more than one way to skin a cat. Crankcase vent hose? No. It will cause a code.
"Can I snake the hose halfway up the intake and let the intake suction pull the Seafoam in?"
Try it out! Who knows, that may work, but since I wanted to make **** sure I get all of Seafoam in, I got up as close as possible.