Not running right -- smoking under hard acceleration

cjman15

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Apr 15, 2004

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Fairfield, PA

May 10, 2005

#1

• May 10, 2005

• #1

my car will run normal and smoke free when i keep it under about 2500-3000 rpm, but once i drop the throttle a little harder and let it wind up some more, i get a pretty steady dark smoke... it's not very heavy or ploomy, just smells and its pretty noticable... i know this is common... what should i check?

 

90mustangGT

I felt sorry for girls because

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Jan 15, 2002

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Dallas, GA

May 10, 2005

#2

• May 10, 2005

• #2

Piston ring blowbye, wore out piston rings.

 

Fink

New Member

Sep 23, 2003

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Melrose MA

May 10, 2005

#3

• May 10, 2005

• #3

Could be Valve seals

 

I_AM_CANADIAN

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Mar 30, 2005

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May 10, 2005

#4

• May 10, 2005

• #4

I thought that when you go open throttle, the O2 sensor "shuts off" and the injectors just blast fuel, causing a rich condition, which then causes back smoke?

 

cjman15

Banned

Apr 15, 2004

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Fairfield, PA

May 10, 2005

#5

• May 10, 2005

• #5

my car has run rich ever since i got it... and i have no cats... so that might have something to do with it

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

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May 11, 2005

#6

• May 11, 2005

• #6

I_AM_CANADIAN said:

I thought that when you go open throttle, the O2 sensor "shuts off" and the injectors just blast fuel, causing a rich condition, which then causes back smoke?

Click to expand...

on foxes, the puter ignores input from the O2's (they still do function at WOT). there is still some fuel trimming going on though. it is on the rich side (vs the SN EEC-IV puters).

 

I_AM_CANADIAN

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Mar 30, 2005

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May 11, 2005

#7

• May 11, 2005

• #7

HISSIN50 said:

on foxes, the puter ignores input from the O2's (they still do function at WOT). there is still some fuel trimming going on though. it is on the rich side (vs the SN EEC-IV puters).

Click to expand...

so then it is normal for some black smoke when under hard accel?

 

cjman15

Banned

Apr 15, 2004

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Fairfield, PA

May 11, 2005

#8

• May 11, 2005

• #8

i'm not at WOT when it smokes, it'll do it with like 1/2 to 3/4 throttle above 3k-3.5k rpm

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

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May 11, 2005

#9

• May 11, 2005

• #9

I_AM_CANADIAN said:

so then it is normal for some black smoke when under hard accel?

Click to expand...

you are correct - it can be normal (relatively speaking). the fuel trim is on the rich side (which is nice. the T4MO puter on the SN's trim a good bit at WOT, which kinda sucks).