Weird Idle- All G owners should take notice!

[tollboothwilley]

Cleaned my throttle body and MAF tonight.

Engine Light came on, I reset it. SES light goes off, but idle is high, about 1100 rpms.

I performed throttle closed position relearn.

Then I performed idle air relearn.

Idle drops to about 900 rpms.

I performed idle air relearn again.

Idle drops to about 780-800 rpms.

I went for a drive and everything seems normal EXCEPT when I am braking. I can feel the transmission dropping RPM & raising RPM. When I feel it go into the next gear down its like the RPMs surge the car forward for a half second and the RPMs bounce to 900 then 1400 a couple times.

Anybody had this happen before?

[BrandAidDesignG35]

vacuum leaks? did you leave a film on the MAF?

I think the relation to braking is that the brakes will use the vacuum pressure inside the engine to power the brakes under light use, my guess is where you preformed the cleaning, it may have affected the air pressure inside the engine, but that's too bad, it seems like everyone has trouble after they clean their throttle body.

Did you clean your manifold/plenum as well? Hopefully someone will chime in with first hand experience, I should be cleaning mine soon too.

[joe603]

Reset the ECU. Try the easy way first (unhook the NEG battery terminal and pump the brakes a few times), then the other more complicated method if the problem persists.

[tollboothwilley]

I did reset the ECU.

I went to check transmission fluid level...I HAVE NO DIPSTICK.

Apparently early 2003's didnt have them??

[BrandAidDesignG35]

*scratches head

Any new symptoms yet? Have you had any more instances with the CEL or trouble codes?

I would suspect it has something to do with your MAF, or throttle body.

What solution did you use to clean? I've heard sea foam is supposed to be good, but again, I have no first hand experience, good luck John.

[tollboothwilley]

i used CRC MAF sensor cleaner and CRC Throttle body cleaner

[tollboothwilley]

i'm gonna try the reset procedure another 10 times if it takes that long to get it right

[joe603]

...this is why I won't clean my TB or MAF.

[tollboothwilley]

ya, me no likely

I got the idle to drop down to 750, which is within spec. Spec is 700 (±50)

[cheapazz]

OK, I gotta ask......why pump the brakes?? This is the only place I have ever heard of that says to pump the brakes. Ancient chinese secret or sumthin????

I've always been told just to turn the key on after disconecting the neg. batt. cable and leave it on for a few minutes....and thats all I do.

Just wondering!

[tollboothwilley]

Its a japanese secret.

Something about Ninja's and their magical ECU's.

You wouldn't understand.

[SteveTheTech]

...this is why I won't clean my TB or MAF.

Nor do I, I only clean a throttle plate by spraying it I never touch them.

Reset the ECU. Try the easy way first (unhook the NEG battery terminal and pump the brakes a few times), then the other more complicated method if the problem persists.

Nice, old school trick. I have seen these procedures but I find them infuriating and they require specific actions. It's like programming remote. That drives me nuts, lol I am spoiled though.

vacuum leaks? did you leave a film on the MAF?

Probably not since the from the description that John provided. PS very cool avatar.

-John I really think that depending on how exactly you did this you might have damaged the throttle motor. Please tell me the key was off when you did this and you didn't force the plate open. It really does not take much to damage the motor. IDK why it is it just doesn't like that. sry. If you cannot get the idle to drop to 750ish on its own and your CEL keeps coming back you might have a problem. That has happened many times that I have seen. I remember in 03 when the electric motors became more popular we were recommending induction cleaning at 30k intervals (as per the product manufacturers "testing" results) the down side to this was the fact that we could never get them to relearn idle or if they would they CEL would come on later, now this did not happen all the time but at a frequency rate that makes me not sell them under normal circumstances and I primarily use them on for very dirty older cars. Most Gs do not really need them if they are properly maintained.

Did you get an ISC system function or a throttle motor circuit/TPS sensor DTC?

If you let me know what code you got I can point you in a better direction.

[SteveTheTech]

Its a japanese secret.

Something about Ninja's and their magical ECU's.

You wouldn't understand.

We professionally refer to it as Secret Ninja Sh*t. If you knew all the wacky secrets that some of these cars have and some of the diagnostic technology you would be surprised.

[tollboothwilley]

Steve, thanks for you help.

I read somewhere that I should try a 12 hour full ECU drain by keeping the neg on the battery off. I took it off tonight, I'll check in the morning.

I haven't had the codes read, but if the SES light comes back on I'll take it to checker to have the DTC read.

Stay tuned.

[smockers83]

I went to check transmission fluid level...I HAVE NO DIPSTICK.

Apparently early 2003's didnt have them??

To my knowledge, none of them do. Whether they do on the newest generation, I don't know. When I first did a routine check of the fluids, I spent a good length of time trying to find the transmission dipstick. I looked all over, couldn't find it. One of the first times I came to this site was for that, found out there really wasn't a dipstick. Why, I have no idea.

[tollboothwilley]

Anything but the early production 2003's should have a transmission dipstick.

You can even buy a replacement at http://www.everythingg35.com

problem with the early 2003's is apparently there are 2 90* bends in the filler tubing. The dipstick won't make or measure accurately if you try.

The Service Manuals have 2 seperate procedures depending on build date/vin #.

[tollboothwilley]

Bad news

I went to the dealership and had them change my transmission fluid since I didnt have the "special" tool required for measuring transmission fluid. $199+tax. I figured its not that bad of a price considering the fluid is like $12 a quart and it takes up to 11 quarts for complete change.

The bad news is that they checked my TB because it wasn't taking the idle air volume relearn. They told me the TB is toast...

In the service manual, apparently, it says not to clean the TB.

Hopefully this is a warning to those of you considering this. It is very sensitive to chemicals. If you are going to do it you should just clean it with a rag, if you clean it all all.

Now i'm on the search of a used TB, hopefully I can find one in a salvage yard or something...

[zozoka1212]

Sorry to hear that bro. Hope you'll find one soon.

zozo

[SteveTheTech]

Hey there John, I changed the title of this thread I hope you do not mind. I feel that this is vital information to many of the members here. Everyone who does or is thinking about doing their own maintenance you can all learn from Johns error. I am not trying to bust your stones, I think your real world experience can show some of the readers what can indeed happen.

As for getting a JY throttle be careful you can't see if it works and most salvage facilities do not take electronic components back. I have seen a few people get aftermarket reman one's and still cannot get it to re-learn the base idle volume. The best advise I feel I can give you is try to save the money and get a dealer re-man. I have done some looking online and Ebay has nothing and most of the dealers that use the same online parts wholesales program all average $530ish. If you get a reman from the dealer I think they are much less. I forget what the specifics but I would guess about half the cost of a new unit. This is not one of those things you should gamble on I know it seems like a lot of money for a small part. It is a crucial part though, it is connected to the CAN system for engine,brake,VDC, and AUTO trans control. Not really something I would gamble with, save up and treat your G to the parts she wants.

[tollboothwilley]

Ya, I think that people need to be aware of this if they are thinking about cleaning their throttle body.

I was quoted $360 from the dealer for a new TB (I'm assuming re-man).

What does it take to rebuild a throttle body?

[SteveTheTech]

I don't even where you would find the internal components and the information that would be required to do it yourself. You may have to bite the bullet. When and if you do get a new one you will know it's clean.

[Jacko3]

I had my Tech clean my throttle body during my last tune up in November. what he was doing and how he did it, was more of an art than science. I could not possibly replicate how he did-----the amount if chemical he used on a rag, how lightly he used the chemical, how lightly he cleaned the throttle body and yet did a great job, how he even managed to get the throttle body butterfly to open and close by maneuvering the shifter and the ignition key without starting the car, are all a mystery to me. My Tech is a wizard and so I am grateful for his expertise.

[SteveTheTech]

I have tried numerous versions of the procedure you described and was unsuccessful at getting the TB to stay open with the key off, or maybe I got busy I forget why I never managed to get it. So this seems to be another thing that is not a DIY job as the cost does not outweigh the potential consequences.

Sounds like you've got a great tech keeping your G up and running.

[tollboothwilley]

Steve, what would you guess cause the TB failure? from the chemical, or from pushing the valve open? What is a primary failing component?

[SteveTheTech]

Steve, what would you guess cause the TB failure? from the chemical, or from pushing the valve open? What is a primary failing component?

I would guess it's a combination of the age/mileage and service, I do not know what the active ingredients are of how they would effect the internal components. I can understand altering the friction capabilities of the throttle plate itself, but I find it hard to believe the chemicals would mess with the devices circuitry. Inside the little black box there is a circuit board that has several sensors and communication devices there is also a motor inside the lower section of the throttle assembly. Random failure are not uncommon in some of the earlier models. This is one of those components that Nissan does not make it self and I am scratching my head on who makes them, but it is a large interntational auto part supplier.

[tollboothwilley]

I would think that either the spring that activates the throttle plate or some sensor was somehow affected when I cleaned it. Whether from my hand or the chemical I don't know.

Thats what I'd like to find out though.

I wish I knew who made them. I'd like to ask them about the components and such.

this place sells reman'd TB's http://www.rockauto.com/catalo...30683

[SteveTheTech]

I will see if I can find one that does not have a core on it. I'll drill out the rivets and see what all is inside. I'll take pics and post them up.

I am guessing Tuesday will be pretty slow at work as all the highways will be closed,although we still have several appointments. we'll just have to see, I think I know where an old throttle motor is hiding just waiting to be disassembled.

Cardone is a pretty big distributor or re-mans. Most people have good luck. That's a great link if it works.

Good Luck. Keep us posted.

[Sentientbydesign]

Steve,

Is there a problem with opening the TB plate when the power is off (key out or battery disconnected)?

How do you keep the plate open? Email me if you don't want it posted here.

Also, I believe Hitachi makes some of the TB components. I remember speaking to someone about MAF and TB circuitry and there were some clues that lead to Hitachi. I'll do some more research and let you know if I find out any hard evidence.

[Jacko3]

Hello Nate:

Here is a link I had earlier posted, to what I saw my Tech do in order to open the TB plate. My car is a 6MT G-35 Coupe. However, opening the TB is only a third of the story. The amount of chemical used in cleaning the TB and how the chemical is sprayed on a rag used in the cleaning and in what amount, seems to be just as important as well.

http://forums.g35club.org/zerothread?id=379999

[Jacko3]

He is an awesome Tech. Even when i go for oil changes, where i don't have to pay more than $15 for service, I try to squeeze $10 at least into his pocket---just because.