Car runs [too ?] rich at WOT.

[RockyTop]

Suspect hi-flow cats may be completely blown out effectively making my car cat-less. Would O2 sims help the perceived rich condition any ? At the track my car puffs black smoke in the brake zones. Though there may be some oil puke (wouldn't that make white smoke ?), my tech thinks I have an overly rich condition. Would ingestyed oil puke make the car run rich or lean ?

 

[ceieio]

When the car is running off the WOT map, it runs in open loop mode meaning that it does not look at the O2 sensors to try to correct the A/F ratio.

If your exhaust opens up and becomes less restrictive, the engine moves toward being lean rather than rich. The injectors are squirting the same amount of fuel while the less restrictive exhaust allows more air to flow through thus generating a lean condition.

I would look elsewhere for the cause.

Oil smoke will tend to be blue / darker colored. White smoke is usually water based.

 

[Sean Roe]

Rocky,
Do a dyno test with air / fuel monitoring. When they reach full rpm and get out of it, have them continue recording the air / fuel ratio. You will find that the stock PCM continues to leave the injectors on when the throttle is closed, causing an excessively rich mixture that results in either black smoke and / or flames from the exhaust pipes.

Sean

 

[SoCal Rebell]

Synthetic oil burns white, I've had the same rich/black smoke problem on the track, this will happen if you drive your car normally on the street and then go onto the track OR if you've disconnected your battery. The computer is re-learning your driving style,and compensates by running rich to "protect" the motor, it usually goes away after a full track day.

 

[RockyTop]

Sean, mine does both ! Love the occasional flames ! Dynoed my car yesterday but they couldn't read the A/F ratio for some reason. Figured out my VEC 1 at setting -18 on the heavy load dial got me appx. 3-4 rwhp from the -16 setting and was still in the upper green/lower blue area.

I was down about 11 rwhp from when I dynoed my car 1.5 years ago just after my track session at VIR with a Hot engine. I wonder if oil puke might have fouled some of the plugs. I am gonna pull a few. Which ones would be most liekly to foul first ?

 

[RockyTop]

SoCal, my symptomatic black smoke in the decel zones usually has not gone away by the end of the day. Which is why I suspect oil puke. Sometimes just after a long/hard decel, when I first get back on ther throttle I see what looks in the rearview like a grayish-white puff of smoke, which is what I thought oil smoke looked like. I cannot see the black puffs on decel, but it is very noticebale to the considerable number of folk behind me and corner workers at Turn 10A at RoadAtlanta (a 150mph to 40 mph in 250 yards braking zone). I wonder if I am getting excessive blow by ? I do not get the symptom on the street noor do I notice excessive oil consumption on the street, but I am gonna start watching it more ! How do you test for excessive blow by ?