So I went out tonight to do some cruising maybe some racing, everthing was cool. I got to mess around with a new M3 and i there didnt seem to be much wrong with my car although tonight, for some reason, was the first time ever since i installed my power FC that the power FC began looking for the idle again out of no where?? Anyway, so one thing led to another and i was on my was on my way home and decided to do a little Top Speed shootout going north on I-55. So i proceeded, 4th gear all the way to 6K and it fit fuel cut... I have a stock fuel system so that was normal but i try to avoid it. Then i shift into 5th and go all the way till 140 and right around there i felt the car just start to die? Just as if I was hitting the brakes, even though i was fucken flooring it?! So i slowed down got off the highway pulled over into a gas station and the rpm was really bad ad really low no matter how hard i got on the gas. at idle the thing sounded like an Industrial Tractor jumping from 300 to 700rpm. I let the car cool down and turned it off for a sec. After a few minutes a turned it back on and black smoke began coming out of the exhaust... I know this is the usual sign of a blown Apex Seal, but im really pissed right now and i just need some of ur input.... And the worst part is i got the car with a brand spanking new engine! and it has only about 5K miles on it right now?! Anyway i really appriciate all your input and also would appriciate some links for taking out my engine.
-TOM

 

I'll be the first..

Check the MAP sensor hose to make sure it didnt blow off.. and hope it did....

Its located on the drivers side firewall.

 

Whats the MAP sensor hose?

 

The hose comes from the back of the intake manifold and goes to the MAP sensor on the drivers side firewall. How much boost were you running? The PFC doesn't hit fuel cut unless you're overboosting. I believe it's .25 kilo's over the setting.

 

Theres a little black box on the firewall that says pressure sensor ( or boost sensor I forget) anyways it has a vacuum line and filter going to the UIM and the Map Sensor.. make sure it is connected at both ends

Its really easy to see/find, but the lower connection to the UIM can be tricky

 

 

happened to me the other day.. popped off.. car totally died when i gave it some gas.. then at idle it was fluctuating from a 200 to 800ish.. then died.. started it up.. smoke.. so right away i thought blown engine.. popped the hood,, check and all that came off was the hose to the map sensor, i put it back on and tie strapped it so it won't come off again.. scary as hell :S

 

Black smoke suggests MAP sensor hose problem rather than blown apex seal. I hope that is all that is wrong.

-Max

 

Well i checked the Map sensor and it seems to be fine, the little black box has a hose comming from the bottom of it and it connects to a place right inbetween the throttle body and the intake manifold... Can anything else cause this?

 

Start the car up, is the engine shaking like a paint shaker?

What mods do you have on the car? I assume the PFC was using a base map?

 

I have: Greddy FMIC, SR underdrive pulleys, Greddy BOV, GEddy elbow, K&N intake, Efini Y-pipe, Dp, Mp, Catback, Power FC (wideband tunned by A-spec) The engine was new when i got the car and has only about 6K on it and its stock ported, the turbos are the original ones set at 11psi and they creep to about 15 when the secondary comes in line...

 

I don't think stock injectors can handle 15 psi with free flowing mods done to the car. Change your plugs see if that helps any.

 

Leading coil

 

why are you getting such major creep?

The most my car wants to creep to is around 12-13 with the same mods.

Isn't it very hard to tune for creep?

Next step is a compression test. Was the motor broken in properly? Who rebuilt it? A rebuild totally depends on who did it. Could last 100k or 1k miles.

Sounds like bad tuning however and very poor boost control.

 

dont curse in title please

 

Yeah if it shakes badly at idle, it may be running on one rotor. time to invest $40 in a compression gage.

 

Im pretty sure i broke in the motor properly, i drove it lightly for the first few thousand miles. The new engine was put in by a mazda dealer, the tunning was done by Steve at A-spec and the boost is controlled by an XS manual boost controller, but as you said i have free flow exhaust and my wastegate isnt ported so that is the cause of the major boost creep.

 

huh??

 

BUMP...

 

I think he might be referring to the primary leads on one of the coils somehow losing a connection, causing you to run on one rotor.

However, I'd get a compression check. Hate to sound pessimistic, but judging by your account of what happened (and your mods), it doesn't sound good to me. Hitting fuel cut should've been your first sign not to push things. The prevailing opinion of many is that the stock fuel system cannot sustain proper a/f ratios beyond 13 psi (and some say even 12 psi), and with your free-flowing intake and exhaust paths mated to a stock wastegate, your boost creep probably raised its ugly head at exactly the wrong time: an extremely high load, high rpm situation (running hard at high speeds).

 

So your saying its most likely a blow apex seal...?

 

Sounds like a blown motor to me.

 

JUST GET A COMPRESSION CHECK, that will tell you if it's the motor or something else. Do that first then come back and let us know the results.

 

ok...

 

Do you have a boost gauge?

Look at the needle when the car is idling.

If the needle is flickering, you have a blown motor.

Anthony