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Old 03-16-2007, 02:56 PM   #1
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Default Black smoke...

So i found out my car blows black smoke at max boost (7-8psi). It blows no smoke at all (except for cold starts) other than that. I beleive this is either the oil return line not descending the whole time to the port on the engine block(stock greddy return line), or some blow by. I think it might be blow by becuse for the first time yesterday i found a little bit of oil lieing in the BOV.

How can i test this, and or fix it?

The engine is high mileage(175k) but its been rebuild around 9k miles ago.
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Old 03-16-2007, 03:00 PM   #2
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Generally black smoke is going to be excess fuel. You might try and see what your afr's are.
-Michael-
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Old 03-16-2007, 03:02 PM   #3
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Originally Posted by TheBandit View Post
Generally black smoke is going to be excess fuel. You might try and see what your afr's are.
-Michael-
hmm that would be great.

Im going to be ordering a wideband soon, or so was the plan.

Just wanna make sure my engines not fucked before i put more money into it haha.
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Old 03-16-2007, 03:08 PM   #4
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too much fuel....probably only happens after 5.5k
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Old 03-16-2007, 03:10 PM   #5
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Sometimes under like half throttle acceleration i'll get a rich spot and dump a huge plume of black smoke out the back. By super rich i mean my wideband will hit like 10.8 AFR.
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Old 03-16-2007, 03:14 PM   #6
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As Braineack says, too much fuel.

One of the problems with the OEM ECU is that the internal map gets rich around 5500 rpm and up. So, if we compensate for boost with rising fuel pressure and a good pump as we increase boost, the ECU causes it to go way rich at higher rpm's because it increases the injector duty cycle in that area.

I think this is why Braineack was trying to change the rising rate of his AFPR in another thread.
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Old 03-16-2007, 03:14 PM   #7
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Sometimes under like half throttle acceleration i'll get a rich spot and dump a huge plume of black smoke out the back. By super rich i mean my wideband will hit like 10.8 AFR.
that's nothing:

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Old 03-16-2007, 03:16 PM   #8
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Originally Posted by olderguy View Post
I think this is why Braineack was trying to change the rising rate of his AFPR in another thread.

yepper! and my damn begi fmu that i got rebuilt still doesnt work properly so i still go to 11:1 after 5.5k.
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Old 03-16-2007, 03:18 PM   #9
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that's nothing:

HOLY CRAP, you're gonna need water injection just to clean out the motor after you get it tuned right. I don't feel so bad now.
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Old 03-16-2007, 03:35 PM   #10
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that's what happens when you dont do your math correctly. its all good now.

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Old 03-16-2007, 03:44 PM   #11
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Maybe your bov is opening.
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Old 03-16-2007, 03:49 PM   #12
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btw, do you have your 1.8L injectors in now? probably dont need them at 5psi.
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Old 03-16-2007, 09:55 PM   #13
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Im running about 7-8 psi brain, should i turn it up a bit?
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Old 03-16-2007, 10:07 PM   #14
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not to thread jack but i am running 6psi should i put in my 1.8 injectors?
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Old 03-17-2007, 12:57 PM   #15
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Quote:
Originally Posted by Fireindc View Post
Im running about 7-8 psi brain, should i turn it up a bit?
what fuel pump?

Quote:
Originally Posted by drftem View Post
not to thread jack but i am running 6psi should i put in my 1.8 injectors?
a lot of factors come into play. what fuel pump, what psi level of fuel, what BHP level?
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Old 03-17-2007, 02:54 PM   #16
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Quote:
Originally Posted by Braineack View Post
what fuel pump?



a lot of factors come into play. what fuel pump, what psi level of fuel, what BHP level?
Its a stock one.
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Old 03-17-2007, 07:13 PM   #17
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The stock pump with 1.6 injectors and vortech (greddy) afpr can supply enough for 6 psi...
There must be an explanation for the black smoke... like (earlier mentioned) a leaking bov, boost leak between turbo and intake...

Sometimes the hoses don't leak on vacuum, but on boost they will.

You should be running lean...on 7-8 psi
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Old 03-18-2007, 11:13 PM   #18
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Quote:
Originally Posted by greddymx5 View Post
The stock pump with 1.6 injectors and vortech (greddy) afpr can supply enough for 6 psi...
There must be an explanation for the black smoke... like (earlier mentioned) a leaking bov, boost leak between turbo and intake...

Sometimes the hoses don't leak on vacuum, but on boost they will.

You should be running lean...on 7-8 psi
i have 1.8l injectors.
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Old 03-19-2007, 01:45 PM   #19
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Again, check for vacuum leaks. You have 7-8 psi, with 1.8 injectors you should be close... Do you have a IC ??

Also , check on the rear off the intake, there is a hose barb capped. Sometimes the rubber is failling. It is used for the automatic transmission.
Also check the pvc valve if you are not venting boost into the valve cover....
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