Smoke at low rpm down shift
#1
Honda-Tech Member
Thread Starter
Smoke at low rpm down shift
That's usually when I see some or if I push the gas at idle Kind of hard. The basemap could be part of the problem.
I'm not running any restrictor it's a t3t4 hybrid china turbo I always let it idle a couple min before shut off. So!
What's best guess? I see noooo smoke while gasing it.
Just a curious thought! Tune Saturday if turbo is fine otherwise it's time to swap on a real charger
I'm not running any restrictor it's a t3t4 hybrid china turbo I always let it idle a couple min before shut off. So!
What's best guess? I see noooo smoke while gasing it.
Just a curious thought! Tune Saturday if turbo is fine otherwise it's time to swap on a real charger
#2
Re: Smoke at low rpm down shift
If it happens on decel it is the valve seals, which is what it sounds like, low rpm when you shift would indicate it happens when the motor pulls hard vacuum.
#3
Honda-Tech Member
Re: Smoke at low rpm down shift
So that's it, if it's decel the problem is def the valve seals? You don't have enough info here to cast a diagnosis in stone. There is more to it then that.
#4
Honda-Tech Member
Thread Starter
Re: Smoke at low rpm down shift
Valve seals don't have much mileage they were changed.
But it does smoke while decelerating
I just happen to notice some smoke I'd like to fix that problem.
But it does smoke while decelerating
I just happen to notice some smoke I'd like to fix that problem.
#5
Honda-Tech Member
Re: Smoke at low rpm down shift
Decel is obviously very high vacuum, the cylinder and head are put to the test under these conditions to see how well sealed up they are. Could be cylinder/piston or rings are damaged or tired. Or it could be something in the valve guide or seals is no good. I find that more often or not its the bottom end that has troubles.
It doesn't seem likely that your turbo could be causing it but you should pull the charge pipe and downpipe off to see. Do a hard decel or downshifts and shut it off immediately when you check things.
It doesn't seem likely that your turbo could be causing it but you should pull the charge pipe and downpipe off to see. Do a hard decel or downshifts and shut it off immediately when you check things.
#6
Honda-Tech Member
Thread Starter
Re: Smoke at low rpm down shift
Fair enough the block is a real old but 190psi across on a cold day. The drain is a -10 braided line tap is like a bit over halfway to the very top of the pan.
Head was resurfaced and rebuilt years back to oem and put on the same
Block.
The oil isn't bad it's fresh.
It needs new plugs.
Head was resurfaced and rebuilt years back to oem and put on the same
Block.
The oil isn't bad it's fresh.
It needs new plugs.
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#8
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#9
Honda-Tech Member
Thread Starter
Re: Smoke at low rpm down shift
Shop might have something to restrict it. The pressure is quite low at those rpm like 20-30psi. If I take a charge pipe off and smoke comes out there going into the engine it's seals if it's dumping in the exhaust what's that? Also seals? Lol
I should mention in the years I owned this engine it burns no oil and doesn't smoke at all in the rpm range I can floor a spooled up gear with no smoke at all. Then I hit traffic a couple down shifts ohhh some smoke going by hmmmm? Lol officer wouldn't like it I don't thibk
I should mention in the years I owned this engine it burns no oil and doesn't smoke at all in the rpm range I can floor a spooled up gear with no smoke at all. Then I hit traffic a couple down shifts ohhh some smoke going by hmmmm? Lol officer wouldn't like it I don't thibk
#10
Re: Smoke at low rpm down shift
yep....I still call valve seals, newer head or not, the seals may be leaking under hard vacuum draw, it could be other things such as turbo or rings, but from MY experience, decel smoke is usually caused by valve seals...
#11
Honda-Tech Member
Thread Starter
Re: Smoke at low rpm down shift
Ok so this will burn oil now then? Maybe it's because Im usin 10w30 reg and
Not my usually 5w syntec
If its getting old that's fine I'll still tune it and use it then.
Any tests I can do?
Not my usually 5w syntec
If its getting old that's fine I'll still tune it and use it then.
Any tests I can do?
#12
Honda-Tech Member
Re: Smoke at low rpm down shift
Pull your down pipe off and check is there is oil in the exhaust housing. You most likely need a oil restrictor on the turbo.
#13
Honda-Tech Member
Thread Starter
Re: Smoke at low rpm down shift
What about open it at the collectOr and check? Much easier. And wouldn't it smoke a lot at 60 psi + oil pressure flooring it? There's none
#15
Retired Moderator
iTrader: (8)
Re: Smoke at low rpm down shift
Since your boosting, Im sure I dont have to point out to you that the basemap is just to get your car to the tuner and nothing else.
It might play a role in your smoking, or could be a handful of other things..
go get a tune before you do some damage that will cost alot more then whatever is causing your smoking issues.
Im thinking rings.. WHY? cuz the OP is running a basemap and ill bet the engine has no crankcase vent and the rings are taking a beating. I f he didnt get a tune tells me quite alot.. So doing a proper crank vent isnt even on the horizon.
EDIT: Decel smoke can be seals.. but since the decel vacuum expands the rings outward, if theyre toast, oil will pass right thru
It might play a role in your smoking, or could be a handful of other things..
go get a tune before you do some damage that will cost alot more then whatever is causing your smoking issues.
Im thinking rings.. WHY? cuz the OP is running a basemap and ill bet the engine has no crankcase vent and the rings are taking a beating. I f he didnt get a tune tells me quite alot.. So doing a proper crank vent isnt even on the horizon.
EDIT: Decel smoke can be seals.. but since the decel vacuum expands the rings outward, if theyre toast, oil will pass right thru
#17
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Re: Smoke at low rpm down shift
There you have it, Block is really old + Turbo + No tune. Could just be that youre rings are going. It could be alot of things, but since the block is old and the motor is not tuned thats my Vote.
If you are burning oil with conventional most likely you would burn even more with a synthetic. Using a thicker oil weight might help band-aid the problem
If you are burning oil with conventional most likely you would burn even more with a synthetic. Using a thicker oil weight might help band-aid the problem
#20
Honda-Tech Member
Thread Starter
Re: Smoke at low rpm down shift
Good call guys I may have started the beginning of lazy rings running it. I beat it like a couple hours (not hard just build boost) and drove it like 7 hours total. Running 13.5-14.5 cruising and 11.5 boosting
Tune tomorrow
The trick is why no oil consumption why no cloud when I stomp on it?
Boost is 3# off spring
It sounds like I drove a lot 80% is just highway at 3800rpm
Tune tomorrow
The trick is why no oil consumption why no cloud when I stomp on it?
Boost is 3# off spring
It sounds like I drove a lot 80% is just highway at 3800rpm
#21
Re: Smoke at low rpm down shift
Running your car without a full tune isn't a good idea in the first place. What you gotta think about is what changed from when it wasn't smoking to now when it is smoking?....you added a turbo. So more than likely its the turbo. Yes it could be rings or valve seals but if all was well before boosting it the usually the turbo is the culprit. Put in a restrictor and I bet it solves the problem. .065 is what's used on most smaller-ish turbos.
#22
Honda-Tech Member
Thread Starter
Re: Smoke at low rpm down shift
Good help everyone. Will update.
Tuner trouble it shoulda been tuned last week! Hopefully all go Saturday.
Motor was super healthy and still runs like a dream if I hurt the rings that sucks
Can't do a compression check atm
Tuner trouble it shoulda been tuned last week! Hopefully all go Saturday.
Motor was super healthy and still runs like a dream if I hurt the rings that sucks
Can't do a compression check atm
#24
Honda-Tech Member
Thread Starter
Re: Smoke at low rpm down shift
Can't do that Either unless I drive 6 hours lol
Or pay the shop. Hoping it's the turbo needs a restrictor for when I tap the gas.
Will look into all suggestions, lol why ask what tests I can do I I'm
Not at a shop.... Just so I have an idea :p
Another example. I could rev to 6 grand and coast in gear but the smoke only
Comes if I'm driving slow and downshift to second for a red light. Or a tap of the gas in the driveway
Not a lot either just a very small cloud enough to see in my rear view then it's gone
Or pay the shop. Hoping it's the turbo needs a restrictor for when I tap the gas.
Will look into all suggestions, lol why ask what tests I can do I I'm
Not at a shop.... Just so I have an idea :p
Another example. I could rev to 6 grand and coast in gear but the smoke only
Comes if I'm driving slow and downshift to second for a red light. Or a tap of the gas in the driveway
Not a lot either just a very small cloud enough to see in my rear view then it's gone