cleaning of throttle body

Post by **Dinkydow** » Thu Jan 09, 2003 5:17 pm

I would like some info: I have an appointment to get some maintenance done on my 94 Q, 52k. I asked for price on cleaning the throttle body, he said what they do is disconnect the fuel pump and run a solution threw which cleans the lines, fuel injectors and the throttle body. Has any one had this type of service done?? What are your opinions? Any other suggestions?? Thanks Wayne

Post by **PalmerWMD** » Thu Jan 09, 2003 5:17 pm

Thats called an injector rail flush, not a TB cleaning.He probaly is a bit confused TB cleanings aren't done as much as they should despite teh great utility they have.

Injector rail flushes are generally a good thing to do as well.In rare occaisons they have dislodged dirt, that then clogged the injector , but that is a calculated risk.They are good practice to do at regular intervals, in the interest of engine smoothness/power/injector longevity.

A TB cleaning ,involves spraying and hand brushing/wiping parts of the intake/throttle body.

Can be done to differnt levels of thouroghness.The $90 dealer job is useful, but you can also get a $350 job which involves taking off teh plenum and hand cleaning the plenum too.

many informed consumers insist on both.

Fred...

Post by **Dinkydow** » Thu Jan 09, 2003 5:17 pm

Thanks for the info Fred, Can I clean the throttle body my self?? I guess you could say I was average at mechanics. Is there anyway you could talk me through it?? Do you think i should have an infiniti dealer do it? Is there anyway one would know whether my Q needs to have it done?? It has 52k on it.. Best regards Wayne

Post by **Mayhem_J30** » Thu Jan 09, 2003 5:17 pm

52k isn't much and you can easily do it yourself.i'll leave this up to a Q owner to write for ya though.

Maybe someone can do a good writeup with pics!!! HINT HINT

Post by **AZhitman** » Thu Jan 09, 2003 5:17 pm

YEAH - What Mayhem said!!! HINT HINT!

Post by **firstq** » Thu Jan 09, 2003 5:17 pm

You will need lots of luck, a second car, lots of time, some special tools, good memory, a lot of patience, a strong back, perseverance, an understanding family, and unfaltering love for the car to do the first plenum job - afterwards, piece of cake. I am doing my 3rd plenum job in as many months - of course I am doing something wrong, but to give you a sense that taking the sucker off subsequently is not the end of the world, as it usually seems the first time.

If you do not have loads of cash on you, the quicker you get hands on with the plenum, the more you will be able to keep that in your pocket - if you are on a limited budget, you will eventually need to start doing your own work on the car - and you would eventually become a DIYer - why not start early and keep some of the green that you may have now?

With your mileage I think a full plenum removal may not be that necessarry - you can do a lot of TB cleaning while keeping the plenum intact. With this mileage, the plenum itslef may not be that gunked up, you need to worry about the passages, and ports for various modules - if you know where the EGR passages, AAC ports, etc are - you may be able to clean them up 80-90% while keeping the plenum intact.

I would suggest taking perhaps the TB off and cleaning it in your hands. Once the TB is out, you can see and access a lot of the stuff inside the plenum and can get access to EGR and AAC ports. Dennis has mentioned several times using a mini roto-rooter to clean the narrow port passages.

Sooner or later your Injectors will/may fail , then (for certain injector numbers) you may have no choice but to take off the plenum, so perhaps wait until then to do the full plenum removal/cleaning. Till then you can work on your back...

Good luck

Post by **Dinkydow** » Thu Jan 09, 2003 5:17 pm

Thanks for info, I know this is going to sound stupid, but I guess I would rather look stupid now then remain stupid, Where is the throttle body? How do I get it off? What do I clean it with??? Would any one have any pictures of the area and maybe a maybe give a small speel on how to do it, short cuts etc. Would be appreciated Wayne

Post by **firstq** » Thu Jan 09, 2003 5:17 pm

Take a look at this picture - the round cylinder like shape is the TB - it is bolted using 4 alan bolts.

http://members.cox.net/azheer/P1010005.JPG

First remove the air filter cover and where it is fastened to the TB neck. Then Remove the TB alan bolts and wiggle it to see if anything else is holding it - just work you up to the point that the TB comes off the plenum.

Post by **911/Q45** » Thu Jan 09, 2003 5:17 pm

You can do a decent job cleaning the throttle body without removing it, just take off the big hose and work through the hole with carb cleaner. You can do a more thorough job if you remove it, but you'd better have the paper gasket that goes between it and the plenum and probably the rubber hoses that attach to the bottom. Those parts often disintegrate when you remove the throttle body.

Post by **Dinkydow** » Thu Jan 09, 2003 5:17 pm

Yea, that is what I have been looking for!!! That makes sense and I know I can do that. Whats the story does carbon get in this area causing trouble? You said spray carb cleaner and work my way through, should I be afraid some of this will seep down into the plenum, or will that be absorbed? I really appreciate your time and advice!!!!! Wayne

Post by **DAEDALUS** » Thu Jan 09, 2003 5:17 pm

Firstq, nice engine bay! I'm always impressed by a clean engine under the hood. Are your EGR and BPT new?As far as cleaning the intake, personally I prefer to clean things off the car. Without knowing how much of the fouling gets stuck in the cylinder, how much get stuck in the exhaust, and how much exits the tailpipe, I feel better if I know all the gunk is on a rag in the trashcan. It is more work, and you will need the parts 911/Q45 mentioned, but it's also a nice warm-up job for other things, like pulling the plugs or removing the plenum. Very educational.

Post by **Dinkydow** » Thu Jan 09, 2003 5:17 pm

ok thanks I think I will plan on doing it off, but I will have to get paper gasket and hoses first, I was quoted $350 by Infiniti dealership to change plugs, how much time would it take me and how bad could I screw up??

Post by **PalmerWMD** » Thu Jan 09, 2003 5:17 pm

Once I was able to clean the inside of the plenum in addition to Tb with lots of carb cleaner and a rag, mmmmmm good.It ws fun knowing a CLEAN plenum cam back on.

When you take teh plenum off be sure to have the full kit of under plenum hoses ready, cuz they are easy to break during this procedure and if u dont have 'em handy then...

Also its always a good idea to renew them every few years or so, anyway, sicne they are exposed to a lot of heat and no one wants a fuel or coolant leak...

Fred...

PS: Acutally $350 for plugs from the dealer is not a bad price, cuz that includes the plenum is off.At that point tehlabor to replace all under plenum hoses should be almost free and the hoses them selves dont cost that much.If you do have uit done at the dewlaer inist and all new plenum hoses, make it <very> clear that you want ALL plenum hoses replaced when they open.Also it wont hurt to say something like out of general interest for sons science project u want the old hoses (keeps 'em honest in case they are out of one hose).Just dont ask for the hoses back implying you dont trust them, just make it like' it a curiosity thing or science project etc.

Post by **Dinkydow** » Thu Jan 09, 2003 5:17 pm

I am glad you replied, I didn't know if $350 was a good price or not and also I didn't know they had to take the plenum off to change the plugs. I am sure glad I found this site, and appreciate all the help you guys give!! Thanks!! Wayne

Post by **DAEDALUS** » Thu Jan 09, 2003 5:17 pm

Actually the plenum doesn't have to come off just to do the plugs. Check out Firstq's engine pic. The plugs are under the black plastic cover bolted to the rocker cover, just under the TB. It IS a lot of work to get to; fortunately the passenger side is much easier to get to. I've never timed it, but I figure maybe 3-4 hours (with experience) just for the plugs, so $350 is at least fair, if not good.

Post by **Chally** » Thu Jan 09, 2003 5:17 pm

It takes me a good 1 to 1.5 hours to change plugs & I have the tools to make it easier.

Post by **Aus94Q45** » Thu Jan 09, 2003 5:17 pm

3-4 hours with experience (and the right tools) for the plugs is about right. However, I do not think that there is a dealer in the US that would take off the plenum and repleace the hoses for $350 or even close. If I recall, all of the hoses and gaskets add up to about $300 and the labor is an easy 6 to 8 hours. I would put the plenum/hose replace in the $800+ range if you are hiring some one to do the dirty work for you. If you want them to hand clean it, add to the price. Also, while its off, time to check or replace the knock sensors and the injector seats. The plugs have some overlap in effort, but not more than maybe ab hour.

Post by **Aus94Q45** » Thu Jan 09, 2003 5:17 pm

Chally, we posted at the same time . . . . you da man! 1.5 hours for the plugs on both sides is fast! I know it can be done, but I always drop something and spend time finding little black allen-head screws in the "hose-forest" under the car! Call me slow, but from the time I pull her in the garage to the time I put away the tools and back her out, 3 to 4 is about right for me. Fortunately, the plugs last for quite some time!

Post by **Dinkydow** » Thu Jan 09, 2003 5:17 pm

Thanks for the comments, I took a good look at the situation last night and I do believe I will save my coin and have the pros do it for me. I live over a hundred miles from the nearest city of any size and if I screwed up, which with all those wire harnesses I could very easily, I would be in big trouble. I know if I was to watch it done once I could definitly do it. As far as the plenum goes I think I will let that go for now because it had a fuel injector replaced 2500 miles ago and you would think if it was real bad they would have told the prior owner about it, they told him about everything else, of course to keep it maintained and them some, what do you guys think about that idea? The throttle body is another story I think I will try to clean it. What are the symtomps of a dirty throttle body??? I have 52k on the Q. Thanks best regards. Wayne

Post by **maxnix** » Thu Jan 09, 2003 5:17 pm

Quote »you would think if it was real bad they would have told the prior owner about it[/quote] From such assumptions are many future expensive repairs born.

Post by **DAEDALUS** » Thu Jan 09, 2003 5:17 pm

Reach in there and grab each hose and squeeze it. If it's fairly soft, like a dense foam, and with no signs of cracking, then they're probably fine.

Post by **landtodd** » Thu Jan 09, 2003 5:17 pm

wayne kos wrote:. . . it had a fuel injector replaced 2500 miles ago . . .

Hi Wayne,

What I have derived reading this forum (and I read it pretty darned closely) is that when one injector goes (most likely from oxygenated gas) the rest are in danger because they've all been exposed to the same noxious fuel mix. Have you used oxygenated gas (read: methanol)? Dennis's latest comment that I read is that T3 doesn't see injector failure unless oxygenated gas is a factor.

Correct me if I'm wrong!

Post by **maxnix** » Thu Jan 09, 2003 5:17 pm

Might as well check your injectors electronically and move the marginal ones to the easier to change locations (1,4,5,8?) that don't necessitate pulling the plenum to change.

Also, it costs about $30 each to clean them and have them flow tested if they are all pulled. Much more reliable than the electronic test.

Post by **Dinkydow** » Thu Jan 09, 2003 5:17 pm

Thanks to everyone who has helped me with this question!! I had called Infiniti on there toll free # just after I purchased the car, before I found this club, I asked about the fuel injector problem, the lady I talked to said that like Todd just said, when one goes you should replace them all. She said when one goes it puts stress on the others. I later talked to a Infiniti service dept, the sevice manager told me no He only replaces the bad one because he did in the past replace them all only to have one go bad in a year or so anyway. I have found some non oxygenaated fuel locally so I felt lucky to find it and will be using it except when I get out of the area, so that should help big time. Thanks again to all. Wayne