: throttle body cleaning



dhs
10-23-05, 08:04 PM
Could someone post step by step instructions on how to clean the throttle body in a 2000 deville? I never did it before, so I don't want to mess something up. About how long should it take to do it?

JimD
10-23-05, 09:28 PM
Remove the air intake plumbing at the throttle body; you might have to remove the top cover of the air filter housing. Just whatever is easiest.

Using throttle body cleaner or catalytic converter-safe carb. cleaner and a toothbrush, scrub the throttle body surfaces paying particular attention to as much of the edge or perimeter of the throttle blade as you can reach. Also the surface of the throttle body where the blade would be at closed throttle. A wooden dowel or soft tool handle will prop the throttle blade open.

Don't be concerned about how much build-up you see on the intake valve side of the throttle blade. Even if you are able to get it surgically clean, the build-up will return after just a few tanks of fuel. Pay attention to the edge of the blade and the bore of the throttle body.

Put the intake air plumbing back together before you start the engine. And don't forget any electrical connectors you removed.

First time = one hour, tops.

pketch
10-23-05, 09:29 PM
It takes a can of intake manifold cleaner. GM sells a very good product. Pull the snorkle from the throttle body and with the car running spray the full can in. This does require you to operate the throttle manually. It will want to stall so you will have to keep the RPMs up. Spray until it begins to load up and then stop. After it is running smoothly again spray some more. If there is a lot gunk on the butter fly make sure you get that cleaned off. Do not spray the MAF sensor(Mass Air Flow) Of course after you have done that, a can of 44K (BG product) in a full tank of quality gas every few fill ups will keep not only the throttle body clean but will also keep the intake, injectors / O rings nice and clean as well. Before doing any maintence such as this check with your GM service department or a trusted technician

dhs
10-23-05, 10:00 PM
Thanks for the info, I wanted to put in the intake manifold cleaner, but I don't want to foul up the plugs which were recently changed. How hard is it too change the back four plugs on a north*? I'm thinking I could put in some old plugs before I do it. Also is there a intake manifold cleaner that I could find at autozone that you would recommend?

Ranger
10-23-05, 10:40 PM
It takes a can of intake manifold cleaner. GM sells a very good product. Pull the snorkle from the throttle body and with the car running spray the full can in. This does require you to operate the throttle manually. It will want to stall so you will have to keep the RPMs up. Spray until it begins to load up and then stop. After it is running smoothly again spray some more. If there is a lot gunk on the butter fly make sure you get that cleaned off. Do not spray the MAF sensor(Mass Air Flow) Of course after you have done that, a can of 44K (BG product) in a full tank of quality gas every few fill ups will keep not only the throttle body clean but will also keep the intake, injectors / O rings nice and clean as well. Before doing any maintence such as this check with your GM service department or a trusted technician
This is not the correct way to clean the TB. It should be scrubbed with the engine off and the throttle plate wide open to clean it good.

Also, putting it in the tank will do nothing at all to keep the TB clean. Fuel is injected at the intake valves, way down stream of the TB. The only thing passing over the TB is air. The carbon build up comes from the PCV gasses in the intake after engine shut down, which condenses on the TB and throttle plate. Follow JimD's advise.

dhs
10-25-05, 04:54 PM
I cleaned the throttle body today and I was suprised how easy it was to do. There was a lot of gunk in there, I used stp carb cleaner which dissolved it very well. It's running smoother now and wot feels much better.

I always wanted to use that stuff that you pour in directly to the engine and it makes a lot of smoke. Does anyone know the name of that product or something equvilent I could find at autozone? Also could someone tell me what is needed to reach the spark plugs in the back?

Ranger
10-25-05, 05:50 PM
The stuff you are talking about is called Seafoam. Never used it but I don't think it is neccassary.

All you should need to get at the rear plugs is a spark plug socket and an extention.

mcowden
10-25-05, 06:52 PM
The stuff you are talking about is called Seafoam. Never used it but I don't think it is neccassary.

All you should need to get at the rear plugs is a spark plug socket and an extention.

Yeah, I'm with Ranger on this one, and JimD's throttle body cleaning advice is correct. I've done it 4 times. It won't help WOT at all unless the blade is crudded up with huge chunks of stuff (highly unlikely), but idle should be more stable perhaps and the throttle won't stick closed. Once you've done this, you might want to disconnect the battery for about 60 seconds to reset the learned idle value. With the clean TB, it might pull a little more air through at idle and throw off the IAC value. Battery disconnect will make it relearn from scratch.

If you have a hard time reaching the 4 rear plugs, you can take off the bolts to move the ignition module to one side. Really, though, that's not even necessary, it's just to get you a little more wiggle room. All you need is the extension necessary to reach down that far plus the ratchet, torque wrench for reinstallation (do NOT overtorque the spark plugs!), and socket.

As far as intake cleaning, I don't think it's worth the time and risk. If you dump in too much of that stuff at once, accidentally or not, you could hydrolock the engine, and then performance will go WAY down REAL fast, as in, gotta take it to the shop to make it move at all again and that's gonna run ya a few clams. If you really feel it needs to be done, which again is highly unlikely, you could use SeaFoam (overrated I think) or I've heard that Chevron Techron fuel injector cleaner works well for that job. Pour it in the brake booster line VERY SLOWLY, and only use about 1/4 bottle.

dhs
10-25-05, 07:33 PM
Weird, I'm pretty sure wot feels alot better now. Before I cleaned it, when I put the pedal to the floor it hesitated for a while, now there isnt really any hesitation and it builds up speed faster. I also cleaned out some of the sensor connectors while I was at it so maybe that did the trick.

I did a tune up on the car recently, but I'm having doubts about the guy that did the job. I asked him to give me the old plugs and now that I look at them theyre denso brand, which have no place in a gm car. I suspect the guy might not have replaced them at all, since I just left him the car and didn't actully see him change them. Ever since that tune up the car's been running a little off and shaking at idle sometimes.

mcowden
10-25-05, 07:39 PM
Weird, I'm pretty sure wot feels alot better now. Before I cleaned it, when I put the pedal to the floor it hesitated for a while, now there isnt really any hesitation and it builds up speed faster. I also cleaned out some of the sensor connectors while I was at it so maybe that did the trick.
I did a tune up on the car recently, but I'm having doubts about the guy that did the job. I asked him to give me the old plugs and now that I look at them theyre denso brand, which have no place in a gm car. I suspect the guy might not have replaced them at all, since I just left him the car and didn't actully see him change them. Ever since that tune up the car's been running a little off and shaking at idle sometimes.

Maybe he put Bosch platinums in there... That's a good way to make it run like crap. :nono:

dhs
10-25-05, 08:11 PM
Yeah I vaugely remeber him saying something about Bosch plugs being good since theyre German. I think he might have put those in. What plugs would you recommend? I see champion platinums are alot cheaper then ac delco, would they be good to use or should I stick with the delco plugs?

mcowden
10-25-05, 08:16 PM
Yeah I vaugely remeber him saying something about Bosch plugs being good since theyre German. I think he might have put those in. What plugs would you recommend? I see champion platinums are alot cheaper then ac delco, would they be good to use or should I stick with the delco plugs?

Yeah, get those Bosch plugs out of there. Junk, pure and simple. The AC-Delcos cost a few bux more, but they are known to work well. Mine started faster and runs much better now that I pulled those pieces of $h1t out of there. That they're German doesn't speak to their quality at all...

85Y
10-26-05, 12:59 AM
IMHO, I'd stick with Delco's, but I have seen a fair amount of the Delco platinums lose their platinum puck on the ground strap (there could have been a design change since then...I keep in mind that these plugs have probably been in cars for at least 5 years, so manufacturing processes get better). I haven't seen any Delco irridiums that had been run for any length of time, so I can not comment on those. Over 4 years, I have seen Bosch single platinum plugs rendomly break the creamic and leave about a 1/3" chunk in the cylinder, which does wonders to the combustion chamber (have seen 2 in person, heard of 3 other occurrences). Bosch single platinums do not seem to run well in a GM, broken or not. Bosch plugs do seem to run well in a variety of imports though. NipponDenso plugs are really a good performing plug, again IMHO. Their longevity seems pretty good as far as their platinum and irridium plugs go. Side note--Accel header plugs are an overpriced Denso plug in a yellow box...but maybe they do chop a quarter inch off the length. Then you have Champion and Autolite. Both seem to have a fairly solid platinum plug at a fair price.

As far as the idle reset procedure goes, what years does this pertain to? On the earlier GMs, they say that driving over a certain speed or holding the engine above a certain RPM in park will reset the IAC valve. Those were also the years that jumpering the ALDL would extend the pintle, then you wait 30 seconds for the IAC to fully extend, unplug it, set the minimum air rate screw, then plug it in and hope the IAC counts aren't pegged high or low.

Ranger
10-26-05, 11:52 AM
RE: Irridiums, I replaced the plugs on my wifes '96 Bonneville at about 110-115K and in hind site was sorry I bothered. The irridium plugs showed no wear. I did it because of a slightly rough idle. Wires alone would have done the trick I think.

dhs
10-26-05, 10:11 PM
Doesn't the 2000 deville have direct ignition instead of seperate plug wires? On the older north*s the plugs and wires are visible and look like theyre a piece of cake to change, however on mine I think the cover is connected to all four. I'll start working on it tomorrow, first off I just want to pull one to see what brand they are, but if someone could give me some hints I would appreciate it.