After cleaning my throttle body, I experienced my engine missing at idle. I found this statement in the Haynes manual (pg 4-9):

Caution: Throttle body on these models is coated with a sludge-resistant material designed to protect the bore and throttle plate. Do not attempt to clean the interior of the throttle body with carburator or other spray cleaners. This throttle body is designed to resist sludge accumulation and cleaning may impair the performance of the engine.

I used the Valvoline SynPower Carb, Choke and Throttle Body Cleaner. I took my car to Nissan and they said to use fuel injections cleaner (BG45) first. It solve the problem for 2 weeks but now the idle is missing again? Any ideas.

 

What do you mean by the idle is missing?

SuDZ

 

My idle stumble periodically after the engine is warm. The engine doesn't die, but just stumbles, like a engine hicup. This happened right after the throttle body cleaning so I think that the cleaning was the cause, or maybe a coincidence. Anyway, now I wished I didn't screw around with the throttle body because there wasn't much of an improvement and I hardly had anything cleaned out.

 

I used the same Valvoline Syntech cleaner and I had zero problems on startup. Maybe you sprayed too much in there! What I did was spray some cleaner, scrub with a toothbrush, and then stick a rag in there to clean up the mess so it doesn't drip too much into the intake pathway.

As for the sludge resistant coating, yes I think there is a special coating, but I don't think you damage it by using TB cleaner. Just make sure you are using Throttle Body cleaner and not Carb cleaner, which I believe is more harsh.

 

I have the same exact problem after cleaning it.

 

After cleaning mine, I haven't had any problems. I used GUNK. I know I got a good cleaning because my exhaust was NASTY while I was cleaning it....

BUT DON'T USE FUEL INJECTION CLEANER!!! I been told by three different Nissan mechanics and one owners manual not to add fuel injection cleaners or octane boosters to the fuel tank. It can cause all kinds of problems.

Clee, Jeff92...can you verify this.....

 

I'm ignorant on this one. I took mine off and used carb cleaner. But then again, I polished my bores also. The gray unmachined portions of the TB. That was about 30k ago. It's probably due again but it's not too bad when I peer in there.

 

Is your car idling normal (around 700) in park? I adjusted my idle back to specifications BEFORE cleaning the TB because it was too low and had to re-adjust it AFTER cleaning the TB because it was too high.

 

You should use the 3M product, throttle plate cleaner

 

i used the valvoline stuff too, only improvements, no problems so far

 

Hm...I think I have similar problems too. I used a carb cleaner as well. The idle is acting a bit weird, but my car is still running fine. So, I don't should I just leave it alone or do something about it. My TB was very dirty when I cleaned it. I might have sprayed a bit too much. I also used one of them fuel injection cleaner that you pour into the gas tank. I haven't notice any problems other than the idle problem.

 

I used the Valvoline stuff too and I have had no problems. It seems half the people have problems and the other half don't.

 

I used the Valvoline stuff and have had no problems at all. Hopefully I dont get any soon (knock on wood) Take Care

 

Maybe your spark plugs are fouled from using too much Throttle Body Cleaner. I had this happen to my 240 some time ago.

Hope this helps!

 

Yeah my buddy had his spark plugs get messed up from doing that also. IT has been a while since then though (dont remember to many of the details) oh well hope everything works out. Take Care

 

Maybe try to blow out that little hole at the bottom of the TB at the edge of the plate with some dry compressed air. May have some debris in that hole which helps regulate idle. Peace: e3 - spamman

 

You should check your idle speed after you clean your throttle body. Most cars idle speed will increase slightly. The ECU will try to adjust it back down. It's possible your getting to much air bypassing the throttle plate and causing your rough idle. To check and adjust your idle speed do the following:

Warm up the car by driving for approx. 5 minuts. Turn off the engine and disconnect the throttle position sensor. Start the engine and observe the idle speed. Most likely it will be high. Using the set screw on the side of the throttle body right by the cables, adjust it back down to about 750 RPM's. Turn off the engine & reconnect the throttle position sensor and start the car to verify correct idle speed. Auto's should idle at 600 in drive and manuals should be about the same in neutral.

 

guys,

Use of throttle body cleaner should not harm in anyway.The carb cleaner does do a lot of harm and it is printed very clearly on the cans telling not to use it on fuel injected vehicles.
After the throttle body cleaning i recommend a plug cleaning, injector cleaning and an oil change at the last.The engine rpm will be a bit high than normal at parking as you have removed all the deposition which alters the amount of air entering your intake.It should return to normal in a week or two.

take care,
Jay

 

I heard this too from my friend who managed a dealer shop.
Nissan actually has an fuel injector cleaner that you can get at the dealers. They recommend using it only every 15K miles.

 

I don't think the TB cleaning has to do with the engine *hicups*. A lot of org members have this same problem and use TB cleaning as a possible solution to their problem after the idle symptoms occur. So far I don't think anyone has come up with a definitive answer as to why the idle sometimes stumbles, but I do know it's a common thing.

 

The Haynes manual is obviously incorrect. There is no "anti-sludge" coating on the inside of the throttle body. The inside is all cast aluminum. Right around the throttle plate, the finish is rougher than right at the inlet, but there is no coating.

You should be able to clean the inside of the throttle body without problem. If your idle is stumbling, it has nothing to do with your throttle body. As long as you didn't bend the throttle plate such that it can't close all the way, ALL of the idle air bypasses the throttle body, ie the problem with a stumbling idle has nothing to do with the throttle body.

 

ditto.

 

and some kid on the forum IS correct...

 

I'm honestly curious - not trying to bag on you:

Are you basing your determination that there is no anti-sludge coating on some kind of knowledge, or just on what the surface looks-like/feels-like to you? An anti-sludge coating may not be something you can see or feel. It could be extremely thin (or clear for that matter), like a clearcoat. I'm just wondering how you're drawing the conclusion that the manual is wrong. If it really is, I'd like to know for sure.

 

I just did the throttle body cleaning a few days ago and I was having the stumbling idle before that. Now I don’t have any problems with idle or cold start up and I have increased throttle response at the lower RPM range (up to roughly 3K).

As mentioned earlier… I would be willing to bet that the IACV (Idle Air Control Valve) may be clogged… assuming of course that the IACV is in fact the little hole at the bottom of the Throttle Body. As a matter of fact, I would be willing to bet that the carbon build up over that hole and not necessarily around the butterfly is why some people are prompted to do this cleaning as a result of rough startup or idle in the first place.

Also, I used Carb cleaner on my throttle body and the engine coughed a couple times when I first started it, but has since run like a champ. If you are spraying enough in the Throttle Body to clog spark plugs or hurt the engine in anyway, then I would say you are spraying too much. The idea (in my mind) is to clean the area surrounding the butterfly and the IACV… mostly because you can actually clean up what you have sprayed, which in turn wipes up the gunk (carbon, grime, etc…). Spraying Carb Cleaner down the throat of your Throttle Body past the Butterfly would do nothing but dislodge a lot of Carbon or Grime and send it right down into your cylinders… where it could cause clogging, or worse. I don’t know about you all, but I could barely get the rag up around the butterfly… let alone past it.

This message is warranted to be reasonably free from defects for its intended usage. Neither the author, nor any of his family members, employers past, present or future, his estate, nor anyone involved in the creation, transmission, usage, modification, or destruction of this message, makes any form of warranty otherwise, and in no way shall any of these be held liable for any damages, direct, indirect, or imaginary, resulting from the use, misuse, abuse, or lack of use thereof.

 

I don't know about the can of carb cleaner you looked at, but the back of my can has directions for using it on fuel injected cars. Hopefully they wouldn't provide directions if it was going to do any damage.

 

I did the same thing, but a lot of people use a toothbrush to get a bit further inside, and that involves spraying more cleaner past the butterfly.

 

Aren't we alittle paranoid???

BTW, nice write up though...I guess too much could be a bad thing and just enough cleaing is just right....

 

No, some 28 year old engineer...that has actually disassembled his entire intake manifold and removed the throttle body and performed hand smoothing on the interior of the throttle body so he knows first-hand what the interior finish and materials of the throttle body...IS.

 

That little hole in the bottom of the throttle body is a vaccuum port to provide vaccuum to other hardware. It is not part of the IACV idle control mechanism. The IACV is located a few inches behind the throttle body on the back corner of the intake manifold. It is bolted to the manifold with a triangular-looking gasket. It is supplied with intake air from a ~3/4" hose that connected to the intake resonator box that bolts to the MAF sensor.

 

I hesitate to get involved in this meaningless competition of phallic sizes… but… there is something you may both want to know.

First… I can’t even verify if you are 28 years old, let alone if you are an engineer – or more accurately, what kind of engineer you are. I was more or less an Electrical Engineer in the Air Force, and I still couldn’t tell you what my pen is made out of (more specifically than plastic)… it would definitely have been a more interesting counter missive, had you used more specific descriptions though. Like what kind of Engineer you are, and what exactly it is that you know the intake is made out of.

Second… That doesn’t give any more credit to the other person’s comment about a coating. Show me a page out of the FSM or get a quote from a Nissan Engineer (not a dealership mechanic – contrary to popular belief, these people did not design the car). I have seen some stuff in those Haynes and Chiltons manuals that was down right false… looking from the page to the part, they just didn’t match up.

In lieu of either of those, I would accept the word of a trusted Nissan Mechanic, or at least one that had established himself as knowledgeable… DB Martin for example has not been prone to Bsing people on this board to the best of my knowledge – although I think I missed him vacating the premises.

After all is said and done though… who cares. I don’t think it is the problem anyway, as I stated earlier. I am an internet expert after all, so I am right and you are wrong!! NA NA NA NA NA NA :-P

 

It idled @ normal RPMs before and after the cleaning without adjustment. My idle was a little rough...but is smoothed out after the cleaning.

 

I cleaned my throttle body without removing it from the car this week. I had no problems after the cleaning. Just my two cents. 2001 Maxima. Runs smoother now.

 

2 cents 15 and a half years ago is now worth 5 cents ... don't sell yourself short.

 

Wow you must have missed the great recession

Dead thread walking...

 

I love it!

 

Did your three Nissan mechanics say why it will cause problems? I thought it was OK to use reputable fuel system cleaners like Techron, etc. I do know that when I bought my 95, my Nissan mechanic at the dealership said cleaners would make the spark plugs run way too hot but the Nissan mechanics I use now from time to time at the dealership said fuel system cleaners are OK and will not make spark plugs run hot. I have never used any cleaners and have always used Top Tier gas but have considered trying one. After reading this, now I'm not so sure. Any other thoughts?

 

The original post was written in February 2002.

Doubt that he is still with us, or owns a 4th gen Maxima any more.

That said, the CRC company makes a product called Throttle Body Cleaner. Which is obviously intended for that purpose. I have used it myself. Yes, I also scrubbed wit a toothbrush.

CRC also makes a product called Mass Airflow Sensor cleaner. Which does a good job.

Each can cost about 8 bucks. But will last for several, or many years.

 

Halloween is over. Please refrain from grave digging.

And be mindful of post dates.