nick

iTrader: (10)

After years of repe***ive TB cleaning my engine is officially fouled with carbon. The PIC shows brand new NGK OEM sparkplugs after 4 days inside the engine and less than 100miles.
Leasson learned: do not overdo TB cleaning !!!



The car runs fine once fully warmned up, but stalls when coming to stop lights, the RPM's just drop, and car dies, starts right back up. there is no CEL light or ghost codes. I've troubleshooting this stalling issue for over a month now and its driving me nuts. I know that carbon fouled spark plugs will make the car stall/miss/hesitate, but in this case it only happens at idle, and when shifting into Reverse.

My IACV is clean and working properly, The TPS checked out fine, the ECTS checked out fine too, the MAF is ok, i have brand new fuel filter, I've checked for vaccum leaks, ignition colis are fine, I've checked the wire harness next to passenger side, gaskets under the IM appears fine, fast idle cam appears to be adjusted correctly, the vaccum hose on EVAP purge cut valve is not damaged ( comonly damaged by FSTB)
The car idles in N at 700rpms, and in D 680, I've searched a lot, and stalling issue when coming to stoplight is a very common, but usually solved by repalcing ECTS or IACV. in my case all of those sensors are functioning properly and i have on CEL codes.

I'm thinking about removing the IM and TB and giving it a through cleaning
I'm wondering, if runing some Seafom through the engine will help the get rid off the black soot caused by repetitive TB cleaning?

If my spark plugs are fouled that bad, I can only imagine what the O2 sensors and catalitic converter look like.

is everybody else's PCV valve was hard to remove? i don't want to pull on it to hard, it's made out of two plastic parts and I'm affraid that one might brake off and get stuck in the IM.

if anyone had similar experience with stalling when coming to stop light,
please share your experiences and possible solutions.

shadyonedeath

iTrader: (10)

Repetitive TB cleaning?

Your saying cleaning it too often will cause this? im confused.

f550maranello2

iTrader: (2)

the cat probably doesnt like that either...

happyricefob

iTrader: (7)

thx for the heads up

the_3d_man

iTrader: (1)

I think maybe throttle body cleaning is not the issue. but whatever. Shouldn't seafoam help clean out your engine?

Batxel

iTrader: (1)

I don't see how cleaning the throttle body can result in this. Something else has to be wrong.

I spray throttle body cleaner on a clean rag and apply it on the area as well as spray it on a toothbrush. Then I go back over the area with a different clean rag. Unless additional airflow hurts the engine and gets the plugs all dirty?

f550maranello2

iTrader: (2)

thats not a bad idea to try that crap now..

Ka$hThaRipper

iTrader: (15)

you can pry it off with a flathead screwdriver..if you try another method, and it does happen to separate into two pieces (which it wont) you can then use needle nose pliers to take it off

nick

iTrader: (10)

You are doing it right and playing safe,
Usually when i'm cleaning the TB , I can not resist the urge to spray few squirts of the TB cleaner down past the butterfly plate.

Plenty of TB down the intake Mainfold = lots of loose carbon fouling up the spark plugs.

But what stumps me is that how long it will take the engine to clean itself up,
I'm kind of pissed off, because i've just installed brand new OEM NGK plugs , and not even 4 days later those are already fouled.

car drives ok, acceleration is ok , it just stalls atleast 3-4 times a day
I'm thinking about removing the TB and cleaning behind the butterfly plate and the TPS plate as well, I know that there will be lots of black gooey stuff which might affect the IDLE control at low speeds.


Nick.

Nick.

shadyonedeath

iTrader: (10)

This is why you clean the intake Manifold also... especially if you have a considerate amount like yours did.

Digitized

iTrader: (9)

isn't that what we are supposed to do when "spraying" tb cleaner?

GodFather

iTrader: (10)

Just how often do you clean your TB? What kind of solvents you've used? When I was 3.0, I always, monthly, used STP ThrottleBody cleaner, or Carborator cleaner, forgot which ever name it was. I've not seen major carbo build ups in the chamber. Of course, now I'm a 3.5, I haven't got the chance to officially clean the TB, yet.

Vlasic

iTrader: (13)

I doubt your routine cleanings are the cause of this. When I clean my TB and all that other stuff I spray almost an entire can of brake cleaner into the TB past the butterfly valve and my plugs have never looked like that.

nick

iTrader: (10)

i have not used anything else but the TB cleaner, any TB cleaner will break down carbon bulid up and turn it into black gooey soot.

shadyonedeath

iTrader: (10)

yea but doesnt TB cleaner evaporate quickly?

njmaxseltd

iTrader: (19)

Cleaning your TB had nothing to do with the condition those plugs are in.
Those plugs indicate an overly rich running engine, which is the reason your stalling out at lights.

Possible causes are: MAF sensor, o2 sensors, ECTS.

crazy97

iTrader: (1)

Your spark plugs will clean up on there own after a 100 or so miles of driving, that's if you have no other current problems. Keep you rpms up a little more than usual, I mean wind out your engine a little higher to help the carbon burn off. My plugs looked like this after starting issues in my sig below and they cleaned up perfectly.

I don't think your plugs are causing the stalling, figure that out and your plugs should be ok.

natty99

iTrader: (6)

I would exert some caution before I make conclusions like the one you made, especially when you make them public and post them as a thread starter. For one, it's misleading to new-comers and two, I just think you're plain wrong. njmaxseltd is with out a doubt correct. You're running rich. Source the problems that make an engine run rich (sensors in the intake and exhaust aspects, etc.) and you have your diagnosis. I know you said that you don't have codes, but there's def something else going on. TB cleaner is pretty darn volatile, so why would there be so much residue left over, and why would it be the source of your problem? Just because it seems like a there is a connection? Unless you're emptying the whole damn can into the intake, I don't see your rationale. If you're going to clean your TB or any part of the intake system, do it right, and do it right the first time. Take your TB off, IM as well and clean the **** out. If you clean it thoroughly once, you don't have to go back in after every run to the grocery store to clean your TB again. Also, you're stalling because when you do come to a stop light, the demand for air is less than at driving speed. Thus, because you're running rich to begin with, there is so little air to mix with the overabundance of fuel at idle that you end up stalling. At least, that's how I see it. Good luck figuring it out. But I can tell you as well that it is NOT your over-ambitious TB cleaning that's at fault. This is how rumors get started!

nick

iTrader: (10)

thanks for all the inputs guys, I'm really confused here, I've checked most of the sensors that have direct input on driveability and they all checked out fine.
I have Auttera scan tool , and my O2 sensors are functionong properly with wide range of lean/rich treshold.
The MAF is working properly, and so is the ECTS.

what else can i check to diagnose rich running engine?
The Hayens manual shows pic of carbon fouled spark plug and says that " Dry sooty deposits indicate a rich mixture or weak ignition. Causes missfiring, hard starting and hesitation"
Recommendation- ensure that plug is in correct heat range, check for clogged air filter or problem with fuel system or engine management system.

I'm using correct plugs, air filter is clean, I have two sets of coils and they both function properly. I'm really confused here.

on the side note, I know that my IM is seriously fouled with black gooey stuff,
once i have removed the IACV to clean it, i've spent aditional hour to clean the black gooey stuff from the little valley right behind the IACV, its where the small EGR tube dumps exhaust gases back to the IM, the passage was seriously clogged with black gooey stuff.

lots of that gooey stuff had to go down through the lower IM and down to combustion chambers, and thats where i come with conclusion that repetitive TB cleaning caused this condition.
of few occasions i've sprayed a lot of the TB cleaner down pass the TB with the engine running !!!!

thanks a lot, please keep the suggestions coming.

natty99

iTrader: (6)

hey nick......i would just stop all the searching at this point and have the next step be a thorough cleaning of the IM and TB post/butterfly plate. Maybe even attack the IACV and EGR again while your at it to really clean that puppy out. With your explanation, I'm thinking that with all the TB you have supposedly used, you have loosened (and continue to loosen) up a great deal of carbon build-up in your engine. And that build-up is slowly but surely eroding off and entering deeper into your intake and eventually getting to your plugs. My thinking is if you thoroughly clean out everything, you'll get rid of the supposed source of the problem. If, however, you're still getting this problem after such a cleaning, I don't know what to say. Good luck though.

nick

iTrader: (10)

yes, thats my next course of action,

i forgot to mention this in the first place, the car sat in the garage for 5 months, while i was on the deployment, i added fuel stabilizer just before i left
the car was already stalling before, thats why i used the TB cleaner so extenisively, it seemed to help for few days, and than back to stalling.

once i got back home, as soonest i started the car for the first time, a big puddle of of black soot shot out of the tail pipe.

i'm thinking that the plates on the TPS sensor are seriously covered with the gooey stuff along with the back side of butterfly plate, causing erratic inputs to the ECM.

this is what i'ne noticed lately, while deaccelerating, the RPM's will drop down to 300-400 range, and than it is really easy to notice that the ECM is trying to bring them back up to correct range, but sometimes they drop off so quick that ECM can correct it, and car stalls.

bear in mind that my car IDLES perfectly at 700rpm's in N with no load, and at around 650 in Drive.
I can hear the IACV tick tick tick while the car is at idle.

crazy97

iTrader: (1)

I would seriously consider taking off the whole upper plenum/intake and spray a few cans of tb cleaner in there until the inside is clean.

smsproduction

Same exact problem. Car was sitting for 4 month because it was dead. Replaced ECM, cleaned starter, eventually started the car, but not before it backfired into intake. It backfired hard, split plastic in half between MAF and TB. I epoxied plastic back together, checked MAF (voltage at idle, 2500rpm and with just ignition on) - OK. But now spark plugs go black. Seems to be running OK when cold. I need to mention that before I had starting problem, but when car was running It was running great. Now it starts no prob, but runs exactly like described by Nick. Also when I put it in gear (auto trans.) rpm would drop, sometime to stall.

maxed_out_99

I don't think over cleaning something is harmful if it's clean it's clean end of story unless your using a super abrasive clean and taking metal away it's not a problem
However I didn't see anyone mention the egr tube. I suggest you seafoam your engine and hook up a scan tool and see how you sensors are responding I doubt over cleaning is a problem as I stated before

FallenOne

iTrader: (17)

First off, clean your IACV, EGR, TB, and MAF.

Pull the codes, If codes are present post them here or fix them.

ef9

iTrader: (8)

I'm sure user maintenance has something to do with it, as my Infiniti I30 came from a guy who was bad at routine maintenance.

The intake manifold was disgusting. I used Seafoam and cleaned only part of the intake manifold (dependent upon where you can insert the chemical). I removed the entire intake manifold and cleaned it really well with Purple Power.

Use Purple Power and a tooth brush. I let the chemical soak for several hours. Don't let that stuff dry out.