gerryk

my race car has begun smoking a little @hi revs and when off the throttle after just being on hard throttle. otherwise it is running fine with the exception of occasional hi rev misfire, I checked my A/F ratio and found it to be running rich ~~around 12.1 @8k rpm. My cel has been on for some time so I checked that and 1 code came up p1415--currentsensor voltage low Airpump electrical circuit. My air pump is gone. Can this code result in altered a/f ratio. And what have you guys who have removed your airpumps delt with this.

davepk

The code listed should not change your AF ratio...

High rpm misfires are something to take very seriously.

I've seen it happen with loose plugs that if left unchecked will destroy an engine when they finally let go.

However, a real high speed misfire would likely result in a code. something you dont seem to have.

Check your plugs and coil packs.

The most likely cause of a high speed "misfire" (or what feels like a misfire) that doesnt throw a code would be a mis-behaving MAP sensor. This will also result in a rich running condition and excess black smoke at high rpm.

After checking all that check your PCV valve and connecting hose for excess oil. Install a catch can if you dont have one. Check the front valve cover vent hose for excess oil and install a can there as well if needed.

gerryk

I did recently change my plugs. I will recheck them. thanks for your input, Gerry

rlaifatt

My experience may be unusual, but I was smoking a LOT coming off-throttle because my flexible catch can (Perrin; made of a section of silicone hose http://www.vividracing.com/catalog/product...products_id/207 ) was collapsing on vacuum and squeezing oil out of the can into the intake manifold. Had to insert a metal sleeve into the silicone can to prevent it from collapsing (one was provided by the manufacturer when I explained what was happening, but I had already installed a tin-can, with both ends cut out, that solved the problem).

Nobody

"I've seen it happen with loose plugs that if left unchecked will destroy an engine when they finally let go."

Happened to me. Reno-Fernley I noticed smoke intermittently after and during sessions. Three weeks later at the next event Plug 2 Blows itself, threads and the coilpack to hell. Car is out of action for at least another few weeks and it has cost me $1500 in parts alone..l.. If the block is damaged I'm really ****ed. CHECK YOUR PLUGS!

Ek9

How does blowing the spark plug out damage the block or anything more than the head threads and coilpack? I mean it's not as if it's that uncommon. Most of the time you just heli-coil the head and drive on. There has to be something more to it than the head threads letting go.

Could you give more details?

I will say, if you don't use a torque wrench when tightening down the spark plugs, you're just asking for this to happen. Overtighten and the aluminum threads are permanently damaged.

davepk

If at the moment the threads let loose the plug and pack are ejected and no bits are left around then you may luck out and not SUCK anything back into the cylinder through the newly created hole at the top of the cylinder.

Ussually no one is that lucky.

Typically the bolt holding the coil pack in place is enough to keep the plug near the top of the plug hole. At that point its probably bouncing up and down as the piston pushes fuel and air past it. This results in a broken plug with all sorts of engine destroying bits falling off it and into the cylinder.

Ek9

I see. Downside of not using spark plug wires I guess. With wires it just blows out of the way. So is that what happened to you Nobody?

Nobody

The Spark Plug and the Coilpack blew out with enough force to break the coil pack off at the coilpack bolt and put a good sized dent in the hood.

I'm meticulous about using a torque wrench when it comes to things like spark plugs. All 4 were torqued with the same setting on the torque wrench and the other three were tight...cyl. 2 for whatever reason just grenaded. I was on a dangerous section of the track when it happened, so I had to leave the engine on and had to accelerate to an access road so as not to get rear ended at 90mph. So I imagine crap got sucked in. ? is is the damage bad enough to constitute replacing the block.

Ek9

Ouch. Sorry to hear that.