C6 ls3 smoke at idle HELP!!
03-29-2014, 08:29 PM
#1
C6 ls3 smoke at idle HELP!!
Okay guys my c6 ls3 a6 is smoking at idle and I can't figure it out!
Compression test/ leakdown test it passed 175/180psi in all holes.
You bring it off idle and it goes away runs fine drives fine no loss of power.
Mods are cold air intake 1 7/8 headers 3" all the way back g6x3 cam stall with nitrous. It's tuned for 91 started doing this in Texas for tx2k. I did use 93 when down there but it's had a couple tanks of 91 since being back. Changed all the spark plugs gap set to .35 Data logged it some ltft at idle are anywhere between 10.5 and 13.0. O2 sensor voltage goes from about 60mv to 780mv at idle. Maf is about 2400 hz map is about 72/75 kpa. I did notice that when I bring the rpm's up to about 1200 the map kpa dropped to about 56 or so. Idk what the deal is. Can anyone help me out ????
Compression test/ leakdown test it passed 175/180psi in all holes.
You bring it off idle and it goes away runs fine drives fine no loss of power.
Mods are cold air intake 1 7/8 headers 3" all the way back g6x3 cam stall with nitrous. It's tuned for 91 started doing this in Texas for tx2k. I did use 93 when down there but it's had a couple tanks of 91 since being back. Changed all the spark plugs gap set to .35 Data logged it some ltft at idle are anywhere between 10.5 and 13.0. O2 sensor voltage goes from about 60mv to 780mv at idle. Maf is about 2400 hz map is about 72/75 kpa. I did notice that when I bring the rpm's up to about 1200 the map kpa dropped to about 56 or so. Idk what the deal is. Can anyone help me out ????
03-30-2014, 06:22 AM
#3
Burning Brakes
Member Since: Jul 2013
Location: Rosewood Heights IL
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Blue/oil smoke at idle and startup are indicative of valve seals. If it lets out a puff when you take off or start it up, valve seals almost for sure.
You can buy replacement FelPro valve seals at a parts store for about $20.
With nitrous, I'd start worrying about ringlands after the simple stuff. But that would be quite a bit of blow by.
You can buy replacement FelPro valve seals at a parts store for about $20.
With nitrous, I'd start worrying about ringlands after the simple stuff. But that would be quite a bit of blow by.
Last edited by dev1360; 03-30-2014 at 06:24 AM.
03-31-2014, 08:09 PM
#5
Cruising
Pull oil cap off and see if u have excessive blow bye at idle. Also if u already did plug change and nothing looked bad in the plugs( signs of oil or coolant burning , or gritty metal on plug) chances are base motor is ok. Also sounds like u did compression check. Do leak down test. Make sure u have less than 20% leakage. Also take coolant cap off while doing leak down test. Let it sit on for a min. Look for consistent bubbles . Just eliminate one component at a time until u find failed component. And without catch can intake will hold oil.
10-24-2023, 09:57 AM
#7
Drifting
What oil are you using? Also, try putting cloth over the exhaust pipe when it is smoking. Do it for a few minutes to get a good handle on oil vs coolant.
And, does it smoke the same from all exhaust tips?
And, does it smoke the same from all exhaust tips?