Smoke at idle fixes, my thoughts and notes

[bnoon]

This is going to be my thoughts/views on the known fixes for the common "smoke at idle" issue. Seems like a get this question at least once a week, so I thought I'd try to condense all my knowledge on the subject to one thread. This is NOT for smoke under WOT or puffs during shifts as the two are not related. I will add/modify/delete for revisions as needed.

In my own personal experience, I started smoking at between 1,000-1,500 miles on the car. This was on the 2 mile trip home immediately after installing my catless DP/RP combo. I had also installed a custom intake at about 100 miles on the car and that didn't make the car smoke at all by itself, but for sure contributed to it by decreasing the vacuum on the intake tubing due to removing the restrictive air box and filter. Think of the PCV system as two ends of a straw with one person sucking on each end. The intake manifold end sucks harder than the TIP end, but BOTH contribute to how much vacuum the crankcase sees. Since the intake manifold end has more vacuum at idle, the flows from the intake boot, through the valve cover, through the crankcase, and and then enters into the engine through the intake manifold barb. Flow under boost will reverse towards the turbo because the PCV closes under boost, the turbo inlet side suction increases as the turbo spools up, which is why we get a little residue in the inlet side of the intake boot. If you have more than just a little residue, you have other issues outside of what will be discussed here.

• Thicker Oil - This worked for me initially, but once the oil got about 1,000 miles or so on it, there would be smoke again. I tried every brand I could think of, cheap to ka-ching, everything smoked eventually and all well before the 3,000 mile change intervals I was using. One thing to note: Royal Purple has my vote. Not that it did any better at preventing the smoke, but that when it did smoke it smelled the best.
  

• Catch can - This didn't do diddly poop for my smoke at idle. I had thought that it worked initially, but after about 100 miles or so I was smoking again. I used the Saikou Michi catch can and Cobb's installation instructions, which called for a second PCV valve installed onto the manifold barb. While it did improve the condition of the oil itself, it did nothing for my smoke issue. In fact, later testing showed that it dropped vacuum to the crankcase adding the second PCV valve due to the restriction of flowing through two PCV valves. MATT DAMOND had switched to a check valve in his kits shortly after I installed my catch can, so I tried that as well and no change on my smoke issue. My testing showed that both of my stock PCV valves would seal to well over 40 psi without leaking. Perhaps those people that this fix worked for were boosting into the crankcase past a dirty/leaky PCV valve? Also, on a related note: Catch can warning for cold climates!!!. Be sure to empty them often in cold climates and/or come up with a way to warm the CC up before emptying it!
  

• Restrictor bolt (AKA bnoon bolt) - I took something from another member's comment that went something like "If someone makes an oil restrictor for our cars, they would clean up". I thought back to my turbo Dodge days from the 80's and we sure did have to run restrictors inline to not smoke on those large turbo swaps too. Could it really be that simple? I started by taking my PTP SST with me to the local auto parts store (The SST was later sold and never installed) and found the thread size/pitch of the oil feed, then a trip to the hardware store for precision drill bits. Install and how to here Oil restrictor bolt install. Initially, I did a .090" hole and got the smoke to drop down quite a bit from the stock bolt. I was waiting to hear back from several rebuilders to see what they recommended for restrictor size and everyone agreed at .060". I didn't try the .060" until after the PTP pill failed to work for me under all conditions. Here's a video of the first oil restrictor bolt that I installed with a .090" hole. It was a step in the right direction as before this install it looked like a bee keeper bug bomb went off and you couldn't even see the back of the car. The .060" and raised idle don't smoke at all
  YouTube - 100 0361

  YouTube - 100 0361

  .
  

• PTP Pill - I tried this next because I was still leery about restricting the flow of the turbo's oil feed because I had done the bolt before I had heard back from the rebuild gurus (which later turned out to be well within the safe range). In theory this PTP would work to increase vacuum across the crankcase by restricting the intake side of flow. But how could this work as vacuum added to vacuum = more vacuum and the pill is restricting vacuum from the inlet side, right? It's a weird phenomenon known as venturi effect. Think of it as a straw that you partially block with a finger as you suck on one end... you can collapse the straw as vacuum from your mouth (intake) increases as the finger (PTP pill) actually restricts overall flow... Upon first install, I still had the .090" restrictor bolt in place. The pill did seem to help initially and was strong in theory, but I was still getting smoking under trailing throttle and at long idle periods (like fast food drive through). Once I combined it with my .060" size bolt, everything was good for quite a while.
  

• Raise the idle - Once ATR came out from Cobb, I had heard from other members here about raising the idle as a smoke fix. Once I finally got an AP with ATR for myself this winter, I decided to do some testing/logging and found that idle vacuum at the factory idle was pretty low at about 8.5 PSI. When I raised the idle to 1,000 RPM, that idle vacuum jumped to just under 11 PSI!!! Raising it higher gained no more vacuum, so that's where I left it. Removing my bolt though made the car smoke again under trailing throttle and when the AC was on. When in defrost and AC modes, it kicks the AC compressor on and increases load at idle, that opens the throttle blade a little more to maintain 1,000 RPM idle, which drops vacuum down to high 9's = enough for my car to smoke during the AC duty cycle. My PTP pill is removed and I now run 5-30 oil again.
  

• Factory Mazda fixes - Turbo - The first fixes from Mazda were replaced turbos. I had mine replaced twice before my semi-mod friendly dealer told me "No more" and I still smoked. The improved seal design may work for some, but it did nothing for me.
  

• Factory Mazda fixes - Redesigned valve cover, TIP, and reflash - While I have not had this fix done due to an aftermarket TIP installed and me not smoking anymore, I still feel that this is a fix in the right direction for those within the factory warranty or those not wanting to get too crazy with the modifications. In theory it will work by moving the upper PCV hose to a higher vacuum area of the intake. Back to the straw analogy, think of it as one person on each end of a straw sucking, with the person on the upper intake end sucking a little harder than before.
  
  I don't know if everyone gets the reflash, and I haven't seen the reflashed settings... but what do you want to bet that it raises the idle?

Ugh... enough typing for now.

[Poohster]

Great write up. Thanks. I think you have made a great assessment of your experience. I read in a book about turbos that too much pressure is an issue as well as too little. One of our fellow MSF members posted this:
some pics of improved turbo.
Showing Mazda updating their K04 with a new oil restrictor on the oil inlet. So you definitely hit the nail on the head. I'll be installing your bnoon bolt sometime this spring. Thanks for research.

I vote for sticky.

[bnoon]

Yeah I saw that thread. I wish I had documented which part number my newest turbo is that's on the car now. Early '09 was the install date if I remember right. If I ever get it, I'll update the first post with my part numbers.

[09speedaddict]

Bnoon, are u still selling your restrictor bolts?

[manelscout4life]

So what actually fixed the smoking?

[m4tic]

Originally Posted by manelscout4life So what actually fixed the smoking?

GT3071

[bnoon]

Originally Posted by sokodude6905 Bnoon, are u still selling your restrictor bolts?

Yes. From time to time they show up on Ebay.

Originally Posted by manelscout4life So what actually fixed the smoking?

The oil restrictor and raised idle did it for me. Prior to me getting the Cobb AP, it took the PTP pill, thicker oil, and the restrictor bolt.

[karl-hungus]

Originally Posted by bnoon Yes. From time to time they show up on Ebay.

not right now ---> boon belt items - Get great deals on Books items on eBay.com!

[bnoon]

Originally Posted by pat failman not right now ---> boon belt items - Get great deals on Books items on eBay.com!

Might help if you spell bnoon right you dolt. EDIT: OK, I just can't be that harsh. I didn't have them up, but still... speeled wright end eet cums up noww. http://cgi.ebay.com/ebaymotors/ws/eB...m=140529933921

[versyejr]

Got any pics of this short ram of yours? Also, what would it cost?

Thanx

[karl-hungus]

Originally Posted by bnoon Might help if you spell bnoon right you dolt. EDIT: OK, I just can't be that harsh. I didn't have them up, but still... speeled wright end eet cums up noww. Mazdaspeed 3/6 banjo bolt restrictor mazda speed bnoon | eBay

lol. i typed bnoon correctly when i searched but ebay 'fixed' my spelling.

i've smoked twice over the years and wanted to confirm if this is the reason why. both times i had my ac running. would that make the difference?

i don't like ac (prefer windows down) but run it when guests are riding with me and this week as i got a tint and can't roll my windows down yet. noticed i was smoking at a light this morning and started putting two and two together.

smoke fixes include: 5w40, occ & ptp pill. probably going to buy your bolt before i trade the ht in for an ap so i can up the idle.

[m4tic]

actually raised idle (1100rpm) and bnoon bolt stopped my smoking. i still smoke at anything <~900rpm and 1000rpm vibrates too much

[Lex]

Very good write-up about this issue.

Another "fix" - keeping slightly higher pressure on the exhaust end with a cat would also help the smoking issues with the stock turbo.

[arrestmered07]

Originally Posted by Lex Very good write-up about this issue. Another "fix" - keeping slightly higher pressure on the exhaust end with a cat would also help the smoking issues with the stock turbo.

Agreed. My car doesn't smoke with cats on but as soon as the downpipe was installed it started smoking at idle again.

[speedtown]

your bolt immediately fixed my problem. I've had the PTP pill in forever and it didn't do shit. I've been meaning to take it out but I just keep forgetting. I've ran 5w30 all winter without any smoking. I've raised my idle to 900 just it case but really if I just ran your bolt I feel confident that's all I would really need.

[kgb]

Do you have a coupon or code....

muahaha.....I just kiddinggggggg.....

Seriously, I am getting this as well..you are the bman

[dizzin9]

bnoon bolt = nope
5w-40 = nope
matt damond's occ = nope
pea tea pee pill = nope
raise idle w/ ap = yes (for 5 mins)
everything altogether = still no

gt3071r (like above poster said) = FUCKING YES





fucking worthless piece of shit stock k04 faggot motherfucking cunt pole smoking bitch! DIE!!!

[meelo88]

damnnit i just had this start happening...looks like i need to get a bolt and play with my ATR.

yay............

[m4tic]

1100rpm

[meelo88]

i'll make my own bolts for now and go to 950 first.

Key word is make my own bolts...either i pull it off in the garage or i gotta go to the machine shop at work...shouldn't be too hard....I just bought 4 bolts in case i mess up some...

We'll see if i can cure this. Since i'm pulling my battery i'll debate the EGR block off plate as well...maybe drill a tiny hole in the plate in that to deal with that issue too so i don't throw a CEL but it removes some of the soot traveling down...it's a drill a thon!

[spike589]

short of gt3071r what else could it be. ive done all of the above and i still barrel smoke out the back at idle and stop lights. the turbo has been rebuilt aswell.

[Poohster]

hey Bnoon,

I just installed your bolt. Idled about 5 mins and no smoke. Generally I would see smoke after 10 mins. I was checking the install. Everything seems great so far. I'll see come summer time. I had a question on the OE banjo bolt. I know the holes are pretty big but could one recycle the OE by blocking up one hole? What possible material could you use to withstand the heat? Just a thought.

[bnoon]

Originally Posted by Poohster hey Bnoon, I just installed your bolt. Idled about 5 mins and no smoke. Generally I would see smoke after 10 mins. I was checking the install. Everything seems great so far. I'll see come summer time. I had a question on the OE banjo bolt. I know the holes are pretty big but could one recycle the OE by blocking up one hole? What possible material could you use to withstand the heat? Just a thought.

You would have to weld both holes and redrill the side hole at .060" to be effective.

Having said that, I would go a totally different (easier) route if you were truly wanting to repurpose the stock bolt. I would drill and tap the center rifle drilled hole for a threaded allen plug, then drill that plug to .060" and epoxy it in place. It's something I looked at doing for my restrictor bolts, but I didn't want to rely on people sending in their core bolts to be modified. In the end, custom drilling the new bolts were cheaper and easier to keep in stock, so that's the direction I went.

[meelo88]

Finally installed my bolt (home-built using bnoon specs) over the weekend with my TMIC install and it seems that all the smoke has stopped.... i will test it after work where i smoked everyone in the exact same spot for 3 weeks straight...however, i just changed my oil to 5W-30....so that may offset it as well...

we shall see...however I want to say that the bnoon bolt works to solve that stupid smoke for me!

Updates to come later...

[bombdotcom]

hey bnoon does ur bolt work right away? i just installed it this morning. took it for a little drive and it smoked like crazy at a light. not sure if it takes a little time to work or not?

[bnoon]

I've never had to wait long at all to know it's working or not. Usually a trip around the block for me when I was testing different combinations out.

Do you have any other fixes installed? I notice you have the AP in your sig, what's your idle set at? My car takes 1000 RPM idle and my bolt to not smoke now and prior to the AP it took the PTP pill, thicker oil, and my bolt to not smoke.

[karl-hungus]

installed mine friday night. as i was blowing into bnoon's to clean it out, i noticed bnoon's smaller hole makes it double as a rape whistle.

[kunfu]

How does the EGR block off plate fit into the picture? Or is it something else entirely?

[bombdotcom]

Originally Posted by bnoon I've never had to wait long at all to know it's working or not. Usually a trip around the block for me when I was testing different combinations out. Do you have any other fixes installed? I notice you have the AP in your sig, what's your idle set at? My car takes 1000 RPM idle and my bolt to not smoke now and prior to the AP it took the PTP pill, thicker oil, and my bolt to not smoke.

I have my idle at 1000 Rpms. Last night it wasn't giving me smoke so hopefully this will do it. We'll see in about a week.

[bombdotcom]

Originally Posted by kunfu How does the EGR block off plate fit into the picture? Or is it something else entirely?

The erg is something completely diff. It goes from the block to the IM. the oem pipe that is. With the block off kit u remove it and put the plate on the block and plug the IM.

[cpolly69]

So about a week before Brad posted this I actually just happened to compile the same sort of information and send it along to Haltech.. with the hopes it could be a sticky and stop a lot of the ? thread that pop up about smoking turbo...
I'm just going to copy what I came up with here -
Basically a large part of it is the same info - but there is also a basic explanation of how the stock pcv system functions in the first place there to help understanding...

PCV - Positive Crankshaft Ventilation
The concept has been around since the muscle car days. Basically it’s an answer to a simple question. How do we dissipate the excess pressures generated in the crankshaft area (bottom of the block)?
In the muscle car days they would simply run a line right from the block with a 1-way valve to the ground allowing a bit of oil and crankshaft area gases to just vent to the air.
This isn’t allowed today so manufactures have come up with all sorts of creative ways of recycling these pressures and pushing them through the engine itself

The MZR uses a 2-way system - pcv pressures flow one way under idle/cruise conditions and go another way under boost conditions

Under Idle/Cruise -
Pressure flows from the intake pipe through the little tube attached into the valve cover and the intake pipe
At idle you should be able to pull this line off and feel a slight vacuum here (at the valve cover input/output) - If you do not this is an indication that something greater may be wrong.
The pressure flows into the valve cover - right where the line attaches (on the inside) there are a series of small baffle chambers - with little holes leading from one chamber to the next - the pressures flow through here - Then into the valve train/cam area -
Next they flow down the timing chain area and mix with the pressures that are naturally being generated by the crankshaft
Next they flow out the pcv valve (located under the intake manifold on the front of the block) - This pcv valve only opens up at low pressure levels that are generated at idle and cruise - and it’s supposed to be one-way only. It’s supposed to block higher pcv pressures that are generated by boost - If it malfunctions, this can be the cause of a number of issues. This pcv valve is mounted inside a small baffle plate that is held on by about 10 or so allan key bolts.
Next the pressure flows through a small rubber line from the valve to the intake manifold.
Once it’s here it goes into the combustion chamber and is mixed with normal air flowing in - It gets burnt and pushed out the exhaust -

Under Boost -
Under boost things flow in the opposite direction -
The pcv valve on the front of the block is closed
All the pressure flows back up the timing chain area into the valve train/cam area
Then through the baffles and out the port on the valve cover
Then back into the line on the intake - Through your turbo - through the intercooler - into you intake manifold and through the combustion chamber…

Why does it smoke??

PCV imbalance is the typically the reason.
What’s imbalanced? If the pressures don’t flow out the front pcv valve as fast as they can come in from the top, what you get is excess pressure in the block -
This excess pressure can push against the drain side of the oil return from your turbo (oil gets pushed into the top of your turbo and then drains out the bottom back into the block)
With the excess pressure pushing again the drain - the oil over-pressurizes inside the center section of your turbo and gets pushed past the seals into the turbine area (exhaust) - It burns and you have smoke out your tail pipe
A downpipe, test pipe, or both can amplify this whole condition. When you add these the turbo is working harder, the center section is spinning faster and more pressures are being produced.

There’s an order of tests and things to do to figure out what’s going on -
1. Compression test - This is a great way to help narrow down what’s happening. Do you really have an imbalance of pcv and oil leaking out into your turbo or do you have a bigger problem? Like oil getting past your piston rings into your combustion chamber? Basically - is the turbo smoking or is your engine actually burning oil?
2. What’s going on at the valve cover? If you pull off your line from intake to valve cover you should feel a vacuum at the valve cover. If you feel pressure coming out of the valve cover you may have compression leaking out of the combustion chamber.
3. Are you sure your pcv valve is good? It’s supposed to be a 1-way valve and only open under idle/cruise. You can pull it and check it’s flow by simply blowing on it - or applying compressed air.

Does an Oil Catch Can fix the problem?
Probably not, but it’s nice to have. Sometimes when pcv pressures come out of the pcv valve on the front of the block they carry oil along with them. The oil can go into the intake manifold and be burnt in the combustion chamber. All an oil catch can is a in/out pressurized can that goes in the line from the pcv valve to the intake manifold. If you install one an additional one way check valve is recommended after the factory pcv valve (as a double check) and make sure you are using high quality/strong lines to hook up the can. Dash 10 lines are strong and can handle the pressure without collapsing.
Since this is connected to your intake manifold - This directly affects your short term/long term fuel trims. If there is anything wrong here you will see it in your trims…

What about PTP’s pill?
PTP’s pill works on the theory that if you decrease the diameter of the hole on the valve cover you will increase the flow inside the valve cover baffles/valvetrain area. - This is kind of like how a shop vacuum work with a smaller attachment. If you stuck a vac gauge in the line on the shop vac and switched from the more open-end attachment to the smaller one (like you use to clean your car) you would see more vac on the gauge. It can work under idle and cruise. The problem is that under boost, it blocks flow out the valve cover when the system is flowing the opposite way.

What about the Bnoon bolt?
The Bnoon bolt restricts the amount of oil going into the center section of the turbo. The thought process here is that if you put less oil in it won’t become over pressurized and leak out the seals. Also, that a downpipe or testpipe or both are actually causing too much oil to be pulled in, in the first place. This may be the case and may actually work, but I personally do not like anything that could restrict oil coming into the center section of the turbo.

Hasn’t Mazda released a fix for this now?
Yes they have
From what the images flying around indicate now - Mazda has changed the design of the valve cover and it’s port. The have also changed the location of the line that runs from the valve cover to the intake. It’s now mounted down lower on the actual inlet vs the intake pipe.
Bottom line is - If you are under warranty, not heavily modded, and you fall under the vin numbers that Mazda has indicated with this bulletin you should stock your car and take it to have these parts installed.

Some advice -
Just keep in mind if your car is in warranty and you want to go and get the dealer to fix the problem; you have to prove to them what is wrong. They will put your car down the path of diagnosis. One path can lead to a new turbo, one can lead to this pcv system, and one can lead to recommendations on different oil. Educate yourself before letting them start the diagnosis and communicate with service reps, managers, and technicians. Let everyone know about your theories about what’s wrong and tell them what you would like to have done.
Always remember, don’t show up at the dealer for anything like this without your oil change records.
If you don’t get the answers out of the dealer that you want, call Mazda corporate. Explain everything in detail.

Mazda North America
7755 Irvine Center Dr
Irvine, CA,
92618-2906
949-727-1990

cpolly69

...got the factory fix (last thing you mentioned)... and it has worked thus far.

They re-flashed the ECU (the stock tune... though I also have the Hypertech tune) and it did not raise my idle rpm.

Car runs much better on both the stock and HT tunes - no stumble & mpg has been climbing.

[meelo88]

glad you had the chance to...from what i read i don't get that same treatment of a new PCV upgrade...

but the oil restrictor bolt worked for me thus far....no problems yet!

Originally Posted by meelo88 glad you had the chance to...from what i read i don't get that same treatment of a new PCV upgrade... but the oil restrictor bolt worked for me thus far....no problems yet!

...sucks that some California dealers won't go to bat for their customers.

Good to hear that the bolt worked for you. Here's to continued success...

[08.5MS3]

Hopefully Brad can chime in on this. With the restrictor bolt in place, how much less oil is the turbo seeing? And are there any detrimental effects because it may be seeing less oil?

[bnoon]

Originally Posted by 08.5MS3 Hopefully Brad can chime in on this. With the restrictor bolt in place, how much less oil is the turbo seeing? And are there any detrimental effects because it may be seeing less oil?

That's the balancing act right there. If you restrict too much, you're keeping oil from the turbo. But... if the oil is pushing past the seal into the exhaust or intake, what good is that oil doing for lubrication? None.

Another point is that we're not starving the oil in the turbo housing. The volume remains the same because even with a restrictor in place, the oil feed side can easily supply MUCH more oil than will actually flow through the turbo center section itself. The same volume of oil is just under less pressure due to the restrictor. Now, important note here, that oil does sit in the center section longer before it cycles through the center section due to the pressure drop and this was one of my main concerns in researching my restrictor options. If the pressure were too low, the oil would stay in the center section too long and "cook". All you have to do to see if this is happening is send in your oil for an UOA, or Used Oil Analysis. I've sent in several and never once had any thermal breakdown on any of the many many oils I've tried.

If you believe that the oil has any issues with cooking, let it idle a full minute or more after hard runs before shutting the car off. This will do more for your oil than the difference in oil supply will.

I've run maybe 15+ thousand miles with the bolt in and 31,000+ miles total and never have an issue boosting to 19-20 psi. That extra psi cooks the oil more than my bolt will and I still have good UOA's.

[kkostec]

After spending hours fighting with my stock downpipe and race pipe to pop in my Turbo XS stealthback exhaust (which is hardly stealthy but amazing nonetheless), I initiated the dreaded cloud of smoke. I just ordered a Cobb Turbo inlet pipe and restrictor bolt. Hopefully these two will resolve my issue.

[G Sp33dy]

how did this work out for you ^^^?

[DuBz]

ok so i just finished making my bnoon bolt, but as i go deeper and deeper into the forums im starting to lose faith. For some, the bnoon bolt is the all mighty savior. For others, they need to raise the idle, throw in thicker oil, get the vent fix, etc. Then there's still other fuckers that say none of these fixes do shit. Seems like i have a 50/50 shot. i have a HT tune so i can only bump the idle up +200( i know i should just get the AP, forgive my brokeness), will that be enough? With all this bullshit being said, will there ever be an end to the dreaded smoking turbo, or is it BT time?

[G Sp33dy]

losing hope fast. BNR is looking better and better every red light i come to...