Steve The Tech & others, Throttle Body Cleaning Issue

[loystock]

I posted in the Q45 forum about this problem but I didn't get a response. Since this is supposedly a known issue with all 2002-2005 Infiniti/Nissan vehicles, I'm re-posting it here so Steve and company can provide some guidance

The car, a 2003 Q45 with 56K miles, had no problem until I did the Throttle Body cleaning. As part of preventive maintenance, every 2 years, I clean the TB, flush the fluids and check the brakes.

After the TB cleaning, I drove the car for a couple of days fault-free, then CEL came on with DTC P0507-Idle Speed Control problem (more than 25RPM over programmed Idle RPM). Per FSM, problem could be with Electric Throttle Control Actuator; Intake Air Leak; or PCV System. I disassembled the intake duct again, checked for any leak source and re-assembled. Per FSM, RE-LEARNING is required any time the Throttle Control Actuator or ECM is disconnected. I did the Gas Pedal and Throttle Valve Closed re-learning and then IAVL (Idle Air Volume Learning). Per spec, Idle at Park/Neutral and NO LOAD should be 650+/-50 RPM. Although the CEL came off, the lowest I can get was 750 RPM. I drove the car for several minutes then as soon as I parked, CEL came on again, same DTC code. The PVCs were relatively new but I removed and cleaned them anyway, including the hoses and tubes. I reset the ECU and did an IAVL again but the lowest is 750-800 RPM. So far the SES is still off but I expect it to come on again.

From internet search, I found out that this is a common problem after TB cleaning (IAVL Fail due no-load Idle >725 RPM)) with 2002-2005 Nissan and Infiniti - per Nissan TSB NTB05-067 and Infiniti TSB ITB05-042. On another Infiniti forum (not NICO) a member posted that it can only be corrected by ECM re-programming, $200 at dealership. Really???

I've been doing this TB cleaning in all the cars for a long time, the last one in Sep' 07. The only difference this time is I disconnected the Throttle Control Actuator connectors to clean and apply dielectric grease.

Is there any one who has a complete copy of the TSB? Should I bite the bullet and take it to the dealership? I know my PCV is good but I will replace them and re-check before going to the dealership.

Rod

[ken in az]

Huh....I have an 06 M45 and mine always idles no load in park at 750rpm - sometimes it'll hit 700rpm but rarely. I attributed it to my exhaust and intake but if yours is doing this then that makes me wonder. Also when I idle for extended periods in the AZ heat with the ac off it'll get to 800rpm and with AC it'll hit 1000-1050rpm.

BTW - I have no CEL indicator and the car drives beautifully. I did check my base timing and it seemed a little low 8-10deg if I recall, but within spec I remembered. I have never checked PCV operation nor disconected MAF or Throttle nor have I cleaned anything.

[loystock]

Please note that this is an issue on 2002-2005 Infiniti/Nissan vehicles. FWIK. your 06 M45 should not be affected.

[ken in az]

Interesting, then I wonder what my problem is?

But to give it the old college try - here's a stab. You may have answered your own question meaning that you'd have to take it in to get reprogrammed. I recall from the FSM that if after closed position learning and idle air learning procedure if it's still out of spec than it needs a visit to the consult to get fixed.

Hope it's just a vacuum line somewhere causing you the high idle - get some carb cleaner and spray around the intake and vacuum lines, if the idle changes then you probably have a vacuum leak somehwere.

good luck

[loystock]

I clean the MAF together with the TB or anytime I disassemble the air inlet duct. The vacuum system is tight. The PCV system in F50 has multiple ports with 2 PCV valves, one on each side of the engine. The PCV valves are mounted on the front side of the engine and are connected downstream of the throttle valve. Two more blow-by tubes are on the rear of the engine, unrestricted, and are connected upstream of the throttle valve.

[ken in az]

exactly the same as the 06 engine

[loystock]

I don't like doing multiple postings but I think this is an important issue to Infiniti car owners.

I'm here at Beshoff Infiniti-San Jose for almost 4 hours now. They have already corrected the SRS recall issue and is now working on the IAVL re-learning. I have printed a copy of ITB05-042 and it clearly states there that IAVL is needed as a result of TB cleaning or disconnecting the ECM.

Per technicians in here, there is a special coating (anti sludge) on the Throttle Body and Plate which can be removed during cleaning. They said that in some cases, ECM re-programming may not work if the TB is 'very clean.' Last time, they have to apply a certain amount of coating (paint?) to get the car to idle per spec. Really weird.

I searched other forums and in the "maxima.org" there is a posting there that per Haynes manual, the TB is coated with sludge-resistant material to protect the bore and plate. Cleaning the TB may impair the engine performance.

In another forum (ford), it is stated that the Ford TB housing has a sticker which stated that the TB should not be cleaned.

Can anybody chime in about this issue? I've been doing TB cleaning for a long time on all the cars I've owned and this is the first time I have encountered this issue.

[Poyzinous]

The Throttle body is very touchy. You dont want to touch it directly, and cleaning should only be with a lint free cloth without moving the butterfly plate. If you disconected it and idle is bad, you may have no choice but to get it reset at the dealer. Long ago, when I was a rookie and steve was sharing his knowledge with me, he said to clean it just rub all the crap away, but later corrected me and said not to move the throttle plate, as the motors inside are uber sensitive.

note: The throttle body in the Q and Y34 M45 is much different from the Throttle body in the Y50 M35. That one is shared with the I35/Maxima and G35 and FX35.

[loystock]

Latest update after almost 5 hours now...the ECM re-programming has been completed but still cannot get it to Idle spec. Service advisor recommending TB replacement. Ouch!!!

I'm going home and think about it.

[SteveTheTech]

Hey all,

Since you have already taken in to the dealer. I am guessing they tried to address the P0507, which is by description means the ECM looses it's idle volume position.

If you have the time and patience to try this yourself I would start by disconnecting the battery for a while. I usually disconnect it and come back to it in 20 minutes or so. Then I would reset the closed throttle position learning. -Make sure that accelerator pedal is fully released.-Key on for ~2 seconds-Key off for 10 seconds (count it)Repeat 5 times. (3 per the book, 5 for good measure)

After that I would start it and warm it up. Then you need to try to perform the manual idle volume learning.

(If the image does not load on your computer click here)

After that I would start it and warm it up. Then you need to try to perform the manual idle volume learning.

If all of that does not work you may have potentially damaged the throttle sensor inside the throttle chamber and there is no fix for that other than unit.

[loystock]

Thanks, Steve. I have done the procedure so many times that I can do it now from memory. and not even using a stop watch.

Here is the latest. The power of reasoning and a little bit of luck....

In essence, the dealership is saying that I shouldn't have cleaned the TB since it is not recommended by Infiniti nor was the usage of any additive in the car. I told them that nowhere in the car manual nor FSM where it is stated TB cleaning is not allowed. As for the after-market additives, it was a generic statement, mainly a CYA for Infiniti at the same time encourages customers to buy additives only from the dealership.

The SA was about to send me home but I told him I need a quote on the TB R&R and that it should be covered by the Powertrain warranty (6/70K) and CA Emission Warranty (7/70K). The in-service date of my car was 14Sep03 and presently has only 56K miles in it. So it should still be covered by both warranties. The SA was surprised by my statement. So he left his office and a few minutes later came back with a 'thumbs-up.'

They have ordered a new TB assembly and will REPLACE IT FOR FREE, under warranty. They will give me a call once the TB has arrived.

In all sincerity, the SA, Bernardo Zeballos and the technicians, Suhaib and Rigo did their best to help me. They re-programmed the ECM and did IAVL several times but just can't get it to spec. I watched them as they re-checked the intake, TB, PCV system, etc. all in vain. BTW, their service area is the cleanest and most organized shop I've ever seen. And their customer lounge has 2 computers available for use by customers. And they will add some more in the near future.

[SteveTheTech]

How did you clean it?

Allot of Infiniti dealers will be more than willing to work with you in some cases with things like this.

When cleaning these throttles there are times you can do everything the way you have done it a hundred times there is always a small chance that will be the time the throttle decides to die.

Next time you try to clean it you should remove the bolts that mount it to the plenum and clean both sides of the plate without moving anything. Another benefit to this type of service is there is not usually a puddle inside the intake that can cause a missfire or catalyst damage on startup.

[loystock]

I disconnect the battery first and then remove the air intake duct. For the TB and plate, I spray carb cleaner on a clean white cotton shirt then wipe the body and plate until almost clean. I slowly open the throttle valve to clean the other side of the plate and body. Final cleaning is with zero-residue contact cleaner. For the electrical connectors and MAF sensor, I only use residue-free contact cleaner. During re-assembly, I apply a thin coat of silicon lubricant on the air duct 'lips' then wipe with cotton shirt. I always apply dielectric grease on all electrical connectors that were disturbed.

I never spray directly into the TB nor plate as the cleaner may seep into the throttle actuator and/or position sensor which may impair their performance. I know about electronics and electro-mechanical stuff. I was an avionics engineer/trainer/consultant/manager for 18 years in the airline and also worked on GE, Pratt & Whitney and Rolls-Royce aircraft engines and related controllers. I switched to semiconductor industry 13 years ago.

Regardless of experience, I consider everyday as a learning opportunity. Any suggestion to improve my knowledge base is always welcome.

[SteveTheTech]

My hat is off to you sir. I would really love to learn jet engines like I know some of these cars. When I was in high school I seriously considering pulling the trigger on avionic technician school, that was in the spring of 01 before everything went to hell.

While I applaud your effort at keeping on top of maintenance items I have to say that spraying the throttle off is much better than touching it. This is something I tend to harp on with the guys in the G35 forums. The micro contact switches inside the TB do not take forced operation well. If the position is off by any amount the computer does not have the capabilities to recognize this and reset the base parameters. It is just a nature of the beast type thing.

At least you are getting a new throttle under warranty. Many people are not so fortunate. At the point when the car is being cared for at home it is usually out of warranty before someone decides to open the hood on their own.

I cannot stress enough that no one should ever touch the throttle plate. This is lesson many season technicians learned the hard way. I remember when these cars were first hitting the mileage at which some chemical companies think your throttle should be dirty and they were facing issues with CELs coming on after the car left, if the car even made it to that point. Infiniti will not say anything about it because from their point of view they tell you and us not too add chemicals to the car so if you do and something goes wrong...

[maxnix]

I clean the MAF together with the TB or anytime I disassemble the air inlet duct.

Cleaning the MAF when it doesn't need it is just inviting malfunctioning and a shorter life for the hot wire elements. If OEM intake filters are changed annually in most environments, cleaning the MAF should not be necessary until ~175K miles.

After market and K&N oiled element filters particularly may also seriously shorten MAF life.

[M35 Sport]

So here is my question. Do you, or do you not clean the throttle body. Every time I go to the dealer they want to sell me the $179 service for this. I have not really look under the hood. But why can't we just turn the ignition to the on position hold down the gas peddle to open the throttle body plate and clean it that way. This is what I used to do on my 04 pontiac. Worked like a dream. I could always tell when the throttle body was getting dirty on that car because it would no longer start on the first crank.

[ken in az]

So here is my question. Do you, or do you not clean the throttle body. Every time I go to the dealer they want to sell me the $179 service for this. I have not really look under the hood. But why can't we just turn the ignition to the on position hold down the gas peddle to open the throttle body plate and clean it that way. This is what I used to do on my 04 pontiac. Worked like a dream. I could always tell when the throttle body was getting dirty on that car because it would no longer start on the first crank.

Nope - we have a cableless throttle body which is controlled by the computer - thus Drive by Wire - The ECU will only operate the TB if it senses a crank signal or in laymans terms - if the engine is running.

Many people have cleaned their TB with success - myself included - but you can run into problems like what Steve the Tech mentions.

[M35 Sport]

Oh okay. The throttle on my pontiac was drive by wire also. But it would still open completely up as long as the gas pedal was down and the ignition was switched to on (not run).

[loystock]

I clean the TB and MAF sensor 4 years after first year of service, then every 2 years thereafter. With the new TB, next cleaning will then be in 2013...that's further down the line. And per Steve's suggestions, I will pull out the plate to clean separately.

I may have the know-how on other stuff but I'd rather listen to the experienced people like Steve on this particular issue.

I have been doing this for a long time, back to the days of carburetor and MAP (not MAF) sensor days. I never have had a problem with the TB until this time. I have never replaced any of the MAF sensor in our cars. Of course my tribal knowledge needs to be updated with this new gas-by-wire technology.

Thanks a lot gentlemen. BTW, I'm back here at Beshoff Infiniti and they are now replacing the TB, followed by ECM re-programming.
Modified by loystock at 3:30 PM 8/12/2009

[loystock]

The TB R&R, ECM re-programming and IAVL completed and out the door in an hour. The No-Load Idle value is right on the money - 650 RPM per printout from Consult. Not a single cent out-of-pocket for all the parts and labor they have done, as everything's under warranty.

I'm very pleased with the service provided by SA Bernardo Zeballos and tech Suhaib. They were very professional in every way. This proves what I have said before - Beshoff Infiniti is really THE BEST Infiniti dealership in the San Francisco Bay Area.