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1994 turbo hatch
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Discussion Starter · #1 ·
ok so tuning my engine. i was out driving and it started smoking and leaking and burning oil like mad so i popped the valve cover and retourqed the head and readjusted valve clearances (mls head gasket so i knew i would have to) and all my woes are gone. except one

when i shift, my afr gauge flashes 16 or 17 before going back to 13-14 and it blows a puff of smoke. also before i fixed my idle occasionally it would lean way out and smoke like mad. it shows up in the log as solid 16.8 (didn’t do the o2 mod) in the 1000rpm x 1000mBar range, and in the range where i actually drive 2500-4000rpm x 1000mbar the log averages it out so it’s a more normal number.

basically smokes at 1000mbar when i revmatch/shift. leaves black grit on my rear windshield. brand new engine with some intense rings so maybe they just haven’t finished seating or maybe it’s my skunk2 proseries intake and 70mm throttle body.

i really would like to know if there’s a way to get rid of that super lean area. it’s only for a fraction of a second but it screws up my logs and smokes
 

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93 Civic HB SI
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ok so tuning my engine. i was out driving and it started smoking and leaking and burning oil like mad so i popped the valve cover and retourqed the head and readjusted valve clearances (mls head gasket so i knew i would have to) and all my woes are gone. except one

If retorquing the head fixed massive amounts of smokege and leakage, I think you've got problems that you're not going to be able to tune out lol.

What are you using to tune?

What was the color of the smoke? I have a hard time believing that retorquing the head fixed an oil burning/consumption problem. If anything, oil would mix with coolant, then you would be burning oil/coolant mix. Outside of having a hairline crack in the head, the oil passages are the furthest away from the cylinders, coolant is the closest. Oil would be leaking externally or into the cooling system, and coolant/oil would be consumed internally. Have you checked your radiator cap/overflow tank for signs of oil? If the head was that loose, you'd have much bigger issues than that. If everything was done right, you shouldn't have to retorque the head honestly. What are you torqueing to?

Valve stem seal issues?



when i shift, my afr gauge flashes 16 or 17 before going back to 13-14 and it blows a puff of smoke. also before i fixed my idle occasionally it would lean way out and smoke like mad. it shows up in the log as solid 16.8 (didn’t do the o2 mod) in the 1000rpm x 1000mBar range, and in the range where i actually drive 2500-4000rpm x 1000mbar the log averages it out so it’s a more normal number.

Are you lifting when you're shifting? If so, then the lean spot is normal. Why would you try to tune an engine where the throttle is lifted and its coasting/not loaded? Think about it, when you lift, ECU cuts fuel so you have no combustion. The exhaust will be full of oxygen, because your engine is pumping atmospheric air into the exhaust, since it is still an air pump. The lean spot is there because there is lots of O2, and is normal. Oxygen Sensors sense the presence of Oxygen, nothing else. Seems you're learning about tuning from scratch :)

What kind of wideband are you using? How has it been calibrated? Where in the exhaust is it positioned?

It's probably puffing smoke during that time, because whatever you're sucking in isn't being burned with the combustion event, it only starts to burn completely when you're back on the power. How is the ECU setup to cut power when you coast? If you're only cutting ignition yet still dumping fuel, then it makes sense you've got a puff of smoke, your dumping fuel out until you get back on it.



basically smokes at 1000mbar when i revmatch/shift. leaves black grit on my rear windshield. brand new engine with some intense rings so maybe they just haven’t finished seating or maybe it’s my skunk2 proseries intake and 70mm throttle body.

You say 1000 mbar, we need more points of reference, is this Gauge or Absolute pressure? How has the MAP sensor been scaled? What kind of MAP sensor is this? Does 1000 mbar mean boost? Or does it mean 0 vacuum/atmospheric? 1000 mbar is 14.6 PSI. Whether that means boost above atmospheric or is absolute atmospheric really matters here.

It's probably not the Intake/TB, unless you have a gasket that isn't sealing right and your leaking coolant into the intake tract somewhere.

If you think base engine is ok, have you checked to make sure your turbo isn't leaking oil, and that its seals are OK? Check the turbine housing, and the compressor side for oil leaks. Make sure you're not pumping oil into the intercooler :) Pull your plugs to see what they look like? What do tops of pistons look like through the plug holes? Are they shiny, oily, or solid black sooty?



i really would like to know if there’s a way to get rid of that super lean area. it’s only for a fraction of a second but it screws up my logs and smokes

If the lean spot only happens when you lift, its fine, that's normal.
This is a seriously loaded question haha.

You can't tune out oil or coolant smoke. Only some fuel smoke.
 

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Formerly weebeastie
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it’s not
filter on black box, filter on VC. pcv valve plugged so it still looks legal 😬

WHY?!?!

It's not turbo is it? Everything but turbo and the PCV should be hooked up. Smoking between the shifts is either too many RPM's, too much internal pressure pushing passed the rings because there is no vacuum on the crankcase to evacuate said pressure (this is what the PCV does), or you've got too much timing in it on the tune and you're burning the rings out of it.
 

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1994 turbo hatch
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Discussion Starter · #7 ·
WHY?!?!

It's not turbo is it? Everything but turbo and the PCV should be hooked up. Smoking between the shifts is either too many RPM's, too much internal pressure pushing passed the rings because there is no vacuum on the crankcase to evacuate said pressure (this is what the PCV does), or you've got too much timing in it on the tune and you're burning the rings out of it.
It is indeed turbo. I think you and rob are right tho i should probably get a catch can because my spark plug tubes are gettin oil in them which means too much crank pressure? and that would also cause the turbo to burn oil iirc??

to answer drt:
you are right i am learning this all from scratch. nobody i know has ever built a performance engine and so its pretty much just me searching forums.
it seems i wasnt clear about where its leaning out. its that brief spot when im letting the clutch out and rev matching, or when pushing in the clutch and letting the gas out. anytime theres around 1000mBar MAP (not boost) in nuetral.
also! before i retourqued the head (to 60 ft-lbs per ARP instructions) it was mostly LEAKING in the spark plug tubes and near the turbo inlet which was then sucking it in and burning it i guess.

anyways i will try to make a catch can with vacuum and see if that helps :)

its a learning experience. i did not know that a pcv needed vacuum but i do now :p
although not my first engine build, its my first modded engine build.
also ive owned other cars since, but this is my first car
 

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Formerly weebeastie
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Awesome man! Try a catch can first. Oil in the spark plug tubes usually comes from where the rocker assembly meets the top of the head. There are O rings under the rocker assembly that get dry and crack. Could also be the top O rings at the valve cover, but generally oil in the plug hole comes from leaky O rings where the Rocker assembly bolts down. That lean spot may be the ECU throwing timing at it when you shift. What software are you tuning with, how are you tuning? Do you have a data log showing what's going on?
 

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1994 turbo hatch
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Discussion Starter · #9 ·
Awesome man! Try a catch can first. Oil in the spark plug tubes usually comes from where the rocker assembly meets the top of the head. There are O rings under the rocker assembly that get dry and crack. Could also be the top O rings at the valve cover, but generally oil in the plug hole comes from leaky O rings where the Rocker assembly bolts down. That lean spot may be the ECU throwing timing at it when you shift. What software are you tuning with, how are you tuning? Do you have a data log showing what's going on?
i’m using honda tuning suite, ostrich and hulog.
i haven’t touched the ignition tables because i really don’t know how they work but it does already pull a bit of timing at that spot…

i hope those o rings are easier to find than the b7 ones smh i had to pull it up on the dealership computer for the guy lol
 

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1994 turbo hatch
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Discussion Starter · #10 ·
ok so this has been asked a billion different ways and a billion different answers, but why can’t you just put the catch can between the stock pcv valve and the black box? then filter on the vc?

see ppl doin all kinds of weird stuff like gutting the valve and sealing black box etc. why would you ever do that
 

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93 4d lx, z6,ported, port matched, compression bumped, balanced, manual swap
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You actually can do that, especially if your rings are seated good, and you aren't pushing too much boost, but beyond like 7 psi it won't be enough and you will need to add vent hoses from the vc to the catch can as well. Just be happy you aren't stuck with CA emissions, my pcv systems sometimes end up very complicated, lol.
 

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BATSLOMAN GIVES NO FUCKS.
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why would you want all the nasty shit being vented from the engine, put right back into the engine? lol
 

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why would you want all the nasty shit being vented from the engine, put right back into the engine? lol
Cause C.A.R.B. says I have to, my catch cans have to have a check valve on a line leading into the intake that produces minimum 1.1inhg vacuum when the engine is under boost, and a functional pcv valve with a heated metal line from catch can to manifold😥 and smog refs dont bribe cheap, sooo...
 

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BATSLOMAN GIVES NO FUCKS.
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you don't count. youre just in occupied naziland lol.
 
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1994 turbo hatch
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Discussion Starter · #15 ·
ok so i’m pretty sure my problem is because i don’t have vacuum to the pcv… right?

so how can you have a vented catch can and still have vacuum?

i plan on running 1 bar of boost eventually (at 5psi rn), so i guess i’ll do the VC now.

turns out the eg PS reservoir has baffles and 3 hose bungs…

why would you want all the nasty shit being vented from the engine, put right back into the engine? lol
?? isn’t that what the catch can is there for?
 

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Formerly weebeastie
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and that's why they get replaced with vented catch cans with drains lol.
This picture makes me smile. Such an old school concept to draw vacuum on a positive venting crankcase set up. Its tried and true and works. The tip that goes in the exhaust (positioning and shape) is fairly crucial. You'll get good vacuum from that
 
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1994 turbo hatch
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Discussion Starter · #18 ·
so you’re drawing vacuum from the exhaust instead of the intake?

what about 2-step?
 

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BATSLOMAN GIVES NO FUCKS.
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so you’re drawing vacuum from the exhaust instead of the intake?

what about 2-step?
the intake just sucks the vapors back into the engine. out the exhaust just gets burnt up. if you used a baffled can with drain, I don't see an issue
 

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1994 turbo hatch
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Discussion Starter · #20 ·
the intake just sucks the vapors back into the engine. out the exhaust just gets burnt up. if you used a baffled can with drain, I don't see an issue
ok i might do that we’ll see. if the PS reservoir works i’ll let you know too haha
 
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