pishta

well, I have to start driving my SC to work again so I thought I would tackle the slight hesitation I had when taking off, sort of a 1/4-1/2 second bog then off to the races. I determined the TB was probably coked so I took an afternoon to take it off and clean it properly. So without any tutorials, I tackled it dry. First: Off come the 3 obvious electrical plugs, TPS, TRAC plate sensor and IAC off the TB. The bellows gave me some grief coming off as they wouldnt compress enough to let go of the plenum or the MAS so I ended up removing the air cleaner assembly (3 10mm bolts) and the MAF (4 10m nuts) probably didnt have to seperate them but no biggie. Next hurdle was the rear 10mm bolt on the TB "air plenum" so after a few minutes, I found it and took it off. Now Im looking at the open TB and the first throttle pate of the TRAC system. Well, mine doesnt work anyways so I cant really get in there to clean properly so off comes the TB. Easier said than done! So off comes the 2 bolts and 2 nuts and all 3 cables from the gas pedal and the cruise control and whatever the third one does. Next comes the vacuum lines and the smallish hose that comes off toward the front of the car. Very stiff hoses! Now the TB can be swung up and I find there is a small rigid hose and a big PCV hose attached to the underside. The small hose is like impossible to remove without breaking the rigid plastic line its attached too so you have to be very careful. The larger one just came off when I swung it up, but it was cracked at the clamp so I ended up replacing it anyway with a section of 5/8 hose I had. Now you have the TB in your hand and its cleaning time. Dont waste your time with the carb/TB cleaner. I did and it literally was a waste of time. The gunk you find behind the butterfly is like tar and the cleaner only softens it but evaporates so fast it just leaves you with a softer tar. It doesnt just melt off like the can says. My method: .99 store oven cleaner! Yup, that stuff cleans like a white tornado. Turn the TB face down so the back of the valve is facing up, spray the oven cleaner on it so it covers it with a foam and let it sit for about a minute. you can scrub it with a toothbrush after about 30 seconds. Rinse it with hot water. (i did it in the deep sink in the garage, stinks like hell so give yourself plenty of ventilation) once that was done, I wedged open the valve and used a wheel cleaner brush to attack the deposits in front of the valve. Spray the cleaner in there again covering the entire bore and scrub through with the wheel brush (or whatever you have) rinse again and youll be shocked how clean that thing got. Repeat if necessary on the stubborn spots, usually right behind the valve and the gasket step. Rinse again and check it out. The oven cleaner totally dissolves grease so you can hit the outside of your TB if it is cruddy too, but it also dulls AL if on too long so spray and rinse after about 5 seconds. rinse and dry. getting everything back is no fun either, the PCV hose was a real PITA as its very stiff, and the rear lower bolt for the TB needs to be run in blind before you tighten any of them. I thought I had wedged something behind the TB as it wasnt seating easily but the lower PCV hose almost sits on the valve cover. Make sure all the cables and electrical is put back, dont forget the vacuum lines and while you have the TB off, its a good time to check your EGR path as the tube is visible in the intake. Mine was completely carboned up to the point that I didnt even recognize the EGR path when I took it off, it was just a big black oval solid puck of carbon.
When it was all finished. I found that I didnt have the hesitation off idle anymore and finding the bellows and the PCV hose were cracked was a plus. I replaced the PCV hose and taped up the bellows so they are both airtight again. Time was about 90 minutes. Happy motoring!