THROTTLE BODY AND MAF CLEANING

[Larz]

Every summer I change the seat filters, air filters, and cabin filter.
This time I am adding two more chores: Cleaning the MAF sensors and throttle bodies. I have the HR engine so I have two of each.
I have no issues with the MAFs but I am slightly concerned over the throttle bodies. I think I remember reading in here that you should NEVER touch the butterfly valve. I will be cleaning both sides of both throttle bodies (engine side and air intake side) so I am curious.

Is it OK to wipe the bodies with a towel on both ends long as I don't manually open / close the butterfly valve? I also was thinking it may be a good idea to disconnect the battery while working on these since the throttle bodies are electronic. I wan to preserve the ECU and idle memory.

Opinions?

PS: here is the video I found on Ebay - very well done, but he doesn't disconnect the battery and there is no "after" info so I have no idea if he had ECU or idle troubles when he finished.

[Costee]

It's a tough call all right! Normally, I'd advise you let sleeping dogs lie if you don't have a scan tool to do a reset should there be an idle problem afterwards. The video suggests all should be all right if you don't pull off the hoses or any other connecting part. But to be on the safe side, I'd say you disconnect the battery for a long while to allow all the power to drain out. And if I'm to kill a fly with a sledge hammer I'd disconnect the battery all night prior
Good luck.

[Ilya]

Yeah just remove the battery. I did wipe down my TB's from both sides of the butterfly valve on my M56x with no harm afterwords. I think things get wonky if you remove them completely off the manifold (like I used to do on my Maxima's).

How are you planning to clean your MAF? Just curious...I might need to do it too. I'm VERY hesitant on touching those though as they can be even more sensitive than the TB's IMO. Nissan MAF's are uber sensitive.

[EniGmA1987]

How are you planning to clean your MAF? Just curious...I might need to do it too. I'm VERY hesitant on touching those though as they can be even more sensitive than the TB's IMO. Nissan MAF's are uber sensitive.

You can use some of that CRC MAF cleaner spray. Just spray it from about 6" away and dont spray too much. A good couple spritz's are fine. Let ity air dry afterwards for a few minutes before reinstalling it, and wait a few more minutes afterwards to make sure it is good and dry before starting the car up. Also make sure you install the MAF back in the correct direction. You can put it in backwards (at least on the older cars)

[EniGmA1987]

As for cleaning the TB, I wouldnt risk it. The reason a dirty throttle body can decrease MPG and cause rough idle would be if gunk was too built up and it did not close to the proper point anymore. Increased airflow at idle means increased consumption so worse MPG. Unless there is significant gunk it doesnt seem to affect much and you would notice idle problems anyway. SO unless you have issues and are having to do idle relearn and all that, I doubt the TB is dirty enough to make a significant difference, and the downside of cleaning is potential breaking of the TB which is a big money fix. Just doesnt seem worth it to me.

[EdBwoy]

I agree.
One caution for the MAF sensor is to do it dead cold. I'm talking about letting the car sit overnight, not even driving it around to reposition it in your garage.

Although I don't encourage anyone to do this, I have cleaned a fair number of Nissan throttle bodies and never ruined them. Battery connected/disconnected, TB mounted/unmounted, ... as long as you don't excessively open the butterfly and play with it. The only reason you need to open the butterfly is to access a thin strip of gunk where the plate meets the TB bore. Typically I wet a napkin with the cleaner and slide it under the plate and it does the job well, or you could use a Q-tip (cotton bud, my non-Americans) to clean as far as you can in a throttle plate closing direction then go to the other side and use the Q-tip gently as well.

However, proper procedure after removing the TB is to replace the gasket. Then there's a slim chance you'd have to do the Idle Air Relearn procedure.

Non-stick cooking pans and Teflon (PTFE)
Here's something I don't see spoken about often. Most throttle plates I have dealt with will have a coating around the hinge, most probably Teflon to help keep the plate motion smooth. Most times, these cleaners will make that coating disappear.
Is that catastrophic? Most probably not right away, but the lack of Teflon makes it that much easier to gunk up and the throttle to stick... ya know, like a non-stick cooking pan with the PTFE scraped off.


My opinion is that this is not necessary, and as EniGmA points out, it skews unfavorably on the potential harm-benefit spectrum based on many user-testimonies.

[Larz]

Yeah just remove the battery. I did wipe down my TB's from both sides of the butterfly valve on my M56x with no harm afterwords. I think things get wonky if you remove them completely off the manifold (like I used to do on my Maxima's).

How are you planning to clean your MAF? Just curious...I might need to do it too. I'm VERY hesitant on touching those though as they can be even more sensitive than the TB's IMO. Nissan MAF's are uber sensitive.

I use the CRC MAF cleaner and get it at my local auto parts shop. As others have said, don't saturate it. Just hold it at different angles and give it a few shots. Then let it air dry for at least 15 minutes before re-installing. First time I did mine, somehow I forgot to re-attach the harness ?!?!?! What a fright when I started the engine, LOL.
RPMs went bonkers, idle went bonkers, etc. I was sat at the wheel thinking what the bloody hell is going on??? Then I realized.

Here is a video from Scotty Kilmer - he's a bit campy, but gives accurate info about pretty much everything.

[Larz]

Thanks, everyone for the input. As always we can depend on other members to share their expertise and that is priceless.

[LIBRILZ]

On VQ37s I have cleaned them, and removed them, but that was only because I was changing spark plugs, if the car runs fine there is no point imo, and from what I know there is a coating to help keep them clean anyways, and the times I've cleaned them, they really aren't that dirty