Cleaning my trucks throttle body.

Philmo · October 31, 2003

i saw some info on cleaning the throttle body with carb cleaner on one of these chevy sites. i can't find it and don't remember where i saw it. i tried yesterday to clean mine, but it was a nogo. i pulled the air duct off and was all set to start the truck up and spray it down, but found that the truck won't start without the duct being on the throttle body. or maybe i'm just stupid. that's possible. hehe. anyway should i spray it down while the truck is off? maybe i'm working on the wrong part of my truck. i don't frikkin' know. i've always been an old chevy with a carb kinda guy. so some of the things on these new trucks test my i.q. a little. i figured if i followed the air filter thru the air duct to the motor, that the air duct would be connected to some kind of apparatus with a big ass butterfly valve. and it was and is. but the d**n truck won't start or stay running with the duct off. and i've always sprayed carbs down while the truck was running. someone please tell me what i need to do to get this done. or point me in the right direction. every now and then especially in times like these, i miss my Quadrajet.

thanks,

phil

TROYROBO · October 31, 2003

mine did the same thing as your's--i just sprayed and used a rag to clean it out--then reattached everything and started it--runs fine now-did it about 20000 miles ago and it has not given any problem yet

raventai · October 31, 2003

the mass air flow meter is that little disk in line right next to the air cleaner, if no air flows through it the computer will release no fuel, so it will not run without the intake tube installed

do it TROYROBO's way

Pancho · October 31, 2003

Just ease the air intake off TB enough to spray the cleaner in the gap. Leave the engine running. Evidently enough air got through the MAF to keep the truck running. I had no problems. My concern though was a post several weeks ago that said that the top engine cleaner is no longer recommended by GM for these trucks.

I am going to look into that a little more before I do it again.

BlackSilver · October 31, 2003

The area you want to clean up is right in the vicinity of the throttle plate ("butterfly valve"). You don't need the truck running. Just spray the interior area down with carb cleaner, hold the butterfly open by hand and use a lint free rag (not a paper "shop towel") to wipe up any crud in the area. Flush it again with carb cleaner and wipe it down a second time. DO NOT spray carb cleaner on the MAF sensor or the areas "upstream" into the ductwork.

Don't start the engine right away --- leave the duct-work off for 10-15 minutes to let things "evaporate". Then put it back together.

You're now "good to go".

MyBigToy · October 31, 2003

I just use a rag saturated with rubbing alcohol. It works great, takes all of the carbon off, and evaporates very quickly.

GMCratblock · October 31, 2003

You should use "throttle body safe" cleaner. Some newer vehicles use a coating in the throttle bore to reduce sludge buildup, and the older style carb cleaners will damage that coating (particularily F*rds). You can get good results removing the air snorkle and tipping open the throttles and wiping the bore with a rag wetted with the cleaner, running engine not required, and the bonus is the dirt removed doesn't go into the engine.

CMNTMXR81 · November 1, 2003

Yup, no MAF reading, no run. Actually if cold it may run in speed density mode, but like sh*t if at all.

I'd clean it without the engine running anyway. But then again I sometimes take the whole TB off and clean it very thoroughly.

2500HD4X · November 1, 2003

I would recommend taking the whole thing off- I did mine a few weeks ago-posted some ?'s on here and got some good info/feedback. It is pretty easy to just take the whole thing off and clean it really well. Take off your air snorkel, disconnect the two electrical connections on the TB, remove the two coolant lines on the bottom (this is the only PITA on the whole thing). Disconnect throttle linkage and Cruise control hookups, remove the three (3) 10mm bolts on the TB and you can pull it out of the truck and clean away. Be careful when you bolt it back up-The intake manifold bolts are set in plastic. I used an electrical contact cleaner on the TB itself-it did really well cleaning the sludge/varnish. It is much easier to get it moving without butterflies sticking at idle. By the way-it is also a good time to bypass the cooling lines to the TB-that is one of the tech tips on the home page on this site. Cooler air=Higher density=More power.

raventai · November 1, 2003

By the way-it is also a good time to bypass the cooling lines to the TB-that is one of the tech tips on the home page on this site. Cooler air=Higher density=More power.

I have asked this before but never a response, does anybody know if there is coolant in the 8.1l's TB ? I have looked around the whole thing and I have not been able to find any coolant lines, the 8.1 is suppose to have a dry intake (no water) so it should not be ported from there

one other thing the 8.1 has no throttle cable, just a small electric motor, I have tried to gently open the plate before but it will not move can we back drive that thing at all or will it damage it? maybe I will try laying a brick on the accelerator pedal (key on engine off)

CMNTMXR81 · November 4, 2003

I haven't actually looked close enough on mine to see if it has a coolant inlet to the TB. But it only goes into the TB! It does NOT go into the plenum. The plenum is called a "Dry" plenum because fuel does not atomize inside of it. Air just flows through it. Anyway, back to the TB. Coolant goes in one end of it and then out another nozzle. The concept behind it is that on cooler and cold days it keeps the incoming air with whatever moisture may be in it from freezing stuff up such as the butterfly and any other part on it that would affect operation.

Bypassing it isn't all to difficult and generally costs less than $5 with parts from a hardware store. Those being a hose connector (so you can butt two coolant lines together and the two clamps associated with securing them to the connector.

The concept behind bypassing it is that cooler, denser air creates more power. If you have air funneling past a coolant soaked hot TB, that takes some of the coolness and denseness out of the air, won't make as much power, hence bypassing it so no hot coolant gets into it will help make power.

I have this done on the Camaro but I cannot document and dyno or butt-o-meter HP gains. It was more of one of those "couldn't hurt and I have the parts already in the garage to fab my own bypass" things. Since I rarely drive it when it's cold out, I don't get too concerned about the TB icing up. If you drive everyday at less than 32* to below zero temps, you may not want to do this.

raventai · November 5, 2003

sory maybe dry was a bad choice of words, what I meant was the 8.1's intake is not used as a coolant outlet / 1/2 of the thermostat housing like a lot of other motors, we have that big cast iron crossover pipe in front of the block