Throttle Body Cleaning Disaster

Status
Not open for further replies.
Joined
Aug 30, 2004
Messages
31,934
Location
CA
The throttle body on my '96 Saturn has always been a bit sticky. It has never been cleaned in 125,000 miles, so it was probably way overdue. Today, I decided to give it a quick cleaning. Or so I thought.

I held the butterfly open and sprayed liberal amounts of carb cleaner into the throttle body. This was done without removing the throttle body. I was able to remove most of the black sludge. However, I noticed that the spray wasn't reaching a small section of the butterfly, so I attached the straw to the can and aimed the straw at that particular spot. This did the trick, but all of a sudden, the straw dislodges from the can and shoots itself into the manifold!
shocked2.gif


My first inclination was to remove the throttle body. With some instructions, it came off without too much trouble. Once the throttle body was off, I could see the straw. It was about 5" into the manifold. I didn't have pliers that were long enough, nor did I have a shop vac. My dad said that he could retrieve the straw, so I let him deal with it. This was a big mistake, as he somehow pushed it deeper into the manifold and the straw fell into one of the runners.

It was already 1 in the afternoon at that point. Book rate for an intake manifold job for this car is 6.9 hours. People on Saturnfans said that the job could be done in 3-4 hours, but I didn't feel like fussing with it anymore. So I called AAA and had the car towed to my mechanic.

Upon my arrival, my mechanic "scoped" the intake manifold with his portable snap-on camera. Of course, the straw could not be found as it had already fallen into one of the runners. He suggested that since the straw was plastic, it would do little, if at all, any harm to the engine. I talked to AcuraTech and he agreed. So, my mechanic loaned me some tools and I reassembled the throttle body and intake in his parking lot.

When my mechanic went to start it up, it barely started. It only started when he revved the engine and cranked it for a long time. Even then, it kept stalling. After several tries and enough smoke to cause a two alarm fire, it finally stayed running. We left it running for about 20 minutes while he worked on another car, and during that time, it ran just fine.

As I got in the car to leave, I made it to the parking lot exit and the car suddenly stalls. I tried restarting it five times without any success. It would crank and attempt to start, but it refused to start. It sounded as though the engine was not getting enough fuel. So I pushed it back into his shop and let my mechanic gave it a few tries. He wasn't successful, either.

By this time, he wondered if the timing chain was broken. Or something else was seriously wrong. Then, he decided to start the car as though it was flooded. Miraculously, this worked. Again, it smoked a lot, but it started and stayed running. He drove the car down to the parts store to pick up some parts and it did not display any problems. I drove it home (8 miles) and it was fine too. I drove it to the local restaurant and back earlier tonight, and it is running just fine. It sounds like there's a slight miss (it always sounds like that) or something, but there are no serious driveability issues.

So, do you guys think the engine will be OK? Is there any maintenance that I should do because of this incident? What do you think happened to the straw? Did it just melt in the combustion chamber?

Thanks.
 
well, if you really used carb cleaner on a fuel-injected engine, that could open a huge can of worms. really you should have used throttle body/intake cleaner, as it is MUCH less harsh on things like injector o-rings, gaskets, sensors, etc. if you got carb cleaner into a MAF/MAP sensor, it's fried for sure. they make an even less harsh maf cleaner for those applications.

as for the straw, it probably melted in that 20 mins that it idled. i doubt a plastic straw would hurt anything.
 
Last edited:
Originally Posted By: hal
well, if you really used carb cleaner on a fuel-injected engine, that could open a huge can of worms. really you should have used throttle body/intake cleaner, as it is MUCH less harsh on things like injector o-rings, gaskets, sensors, etc. if you got carb cleaner into a MAF/MAP sensor, it's fried for sure. they make an even less harsh maf cleaner for those applications.

as for the straw, it probably melted in that 20 mins that it idled. i doubt a plastic straw would hurt anything.


Yes, I probably should have used throttle body specific cleaner. But the carb cleaner did not come in contact with any sensors, o-rings or gaskets.
 
Now you know why you should never use the straw if there's even a remote chance of it getting lost in the internals.
 
The active ingredients on the carb cleaners I've looked at are acetone, xylene, toluene, and methanol. Ditto for throttle body cleaners. It seems as though there isn't much difference.

Quote:
Then, he decided to start the car as though it was flooded. Miraculously, this worked.


It's pretty normal to have to do that after cleaning the throttle body if you don't do it with the engine running.
 
Quote:Then, he decided to start the car as though it was flooded. Miraculously, this worked.


yeah, that has nothing to do with the straw. It's the carb cleaner.
 
I like cleaning the TB with the engine running. I figure that cleans the intake valves, too.

Cleaning the TB with the engine running appears to be the only way to do it without setting a code on my Saab 93. If you move the throttle plate, even with the engine off, key off, it will set a P1523 code because it continues to monitor the position of the throttle plate. (Yes, it's drive-by-wire).

Actually, I think if you wait long enough (an hour or so) after you shut the engine off for the ECU to go to sleep, you can move the throttle plate to clean it without setting a code.
 
yeah, i do it with the engine running, also. modulate the throttle while spraying the intake/TB cleaner in there, keeping the motor running by doing so. i would imagine this cleans deeper than doing it with the engine off, plus avoids hard starts b/c u can burn up the cleaner right away.
 
wow, critic. your doing alot of maintenance on your saturn lately. I'm sure that plastic straw melted. All that smoke was probably from the carb cleaner or the liquid straw melting. hopefully no damage was done.
 
Last edited:
Carb cleaner and TB cleaner are essentially the same thing, TB cleaner is probably a little milder and that is what I would use. As others said the straw is long gone, plastic petro-chem product melted burnt, and out the tail pipe. You probably gave it a really good dose of carb cleaner and experienced the same thing as sucking something like Sea-Foam through a vacuum line. No harm no foul, just stress and some ripped out hair.
 
I certainly wouldn't worry about the straw, it's long gone. On my car, I can't clean the throttle plate running as I take off the ICS motor, clean the pintle on the end of it and spray the passageways where the air goes. This helps a problem the cars has idling a little rough when the outside temp is below 40 Deg F. Oh Yeah, the smoke was just flooding from the cleaner. Perhaps you used a bit much.
 
I wouldn't worry about the initial hard start, smoking and stalling. Spray cleaner can hang around in the nooks and crannies of the IM for a few start/stops. As far as the straw goes? Like everyone else says, forget about it.

Joel
 
I did the same thing on my wife 97 SC2. Every once in a while her car will not start and a quick spray helps out. Straw gone. I told her not to worry. The car is always hard to start after spaying. Once the computer figures out the changed parameters it runs fine. This can take a few minute. Letting a car idle for a long time does not allow the BCM learn normal operating parameters.
 
Originally Posted By: gregmp
I did the same thing on my wife 97 SC2. Every once in a while her car will not start and a quick spray helps out. Straw gone. I told her not to worry. The car is always hard to start after spaying. Once the computer figures out the changed parameters it runs fine. This can take a few minute. Letting a car idle for a long time does not allow the BCM learn normal operating parameters.

Thanks!

Someone said that I might have contaminated and ruined the oxygen sensor. Did you experience this issue with your Saturn after the straw incident?
 
DON'T USE CARB CLEANER on TB for there are some types of TB where the butterfly shaft is coated (most likely some kind of polymer coating) that certain types of CARB CLEANER will melt/damage it.

Get CRC TB spray when in doubt. Also read the instructions to see if it explicitly mentions the coating on the TB shaft, I would stay away if not mentioned (I believe CRC actually did mentioned in on it's label).

Q.
 
remember what your mother told you.... A little bit goes along way! Next time spray the cleaner on a rag then wipe the crud out. But if you insist on spraying it in leave the throttle closed and let it slowley seep past the throttle plates.
 
Originally Posted By: brianl703
Cleaning the TB with the engine running appears to be the only way to do it without setting a code on my Saab 93. If you move the throttle plate, even with the engine off, key off, it will set a P1523 code because it continues to monitor the position of the throttle plate. (Yes, it's drive-by-wire).


Can't you just disconnect the battery?

How do you move the throttle plate to clean it with the engine running without setting a code? I assume moving it directly w/ your hand would cause a code -- do you have somebody work the gas pedal for you or is there some trick?

I've wondered about this on DBW cars. Having a cable to work is convenient for maintenance...
 
No one in particular:

Why does everyone believe the straw melted? It's made from a nylon like material, it's not made from styrene etc, because it has to be resistant to petro-chemical solvents. Nylon survives 214°F just fine. Neither a throttle body nor an intake manifold gets very hot.

Let's say the straw got sucked into the IM, which we must assume, or it wouldn't have disappeared from the TB. If the IM is equipped with flaps inside the runners, the straw may well be jamming a butterfly valve. How hot does an intake manifold get? On my car, the IM gets warm but not over 150F°F or so at idle, after a drive its temperature is closer to ambient air temperature. I don't see an intake manifold getting hot enough to melt the straw.

If the straw makes it into the combustion chamber, it will surely be blown to bits and exit through the exhaust valves, with the residue getting stuck on the porous catalytic filter element.
 
Originally Posted By: rationull
How do you move the throttle plate to clean it with the engine running without setting a code? I assume moving it directly w/ your hand would cause a code -- do you have somebody work the gas pedal for you or is there some trick?

I've wondered about this on DBW cars. Having a cable to work is convenient for maintenance...


My car is not DBW and has a throttle cable. However, the engine will not run with the intake plenum pulled off the throttle body. I always (twice over 180k miles) remove the TB to clean it. Four bolts need to be removed and the TB gasket needs to be replaced. If no spare gasket is at hand, a milk carton can be used to fashion a polyperse wax coated paper gasket.
 
Status
Not open for further replies.
Back
Top