Why my engine blew?? Bad air/fuel mixture?

[Travis_GST]

Im trying to figure out why my engine blew and if maybe it was getting too much air in the air/fuel mixture. With the performance upgrades I had, upper/lower piping, K&N Intake, electric exhaust cutout and boost controller (although not turned on) my dad thinks it was getting too much air. I tried telling him that with the boost controller turned off, its getting the same amount of boost air that it does if it was stock, thus the fuel/air mixture should be the same. Does that sound right? Im going to have to sell pretty much all my aftermarket stuff since he is the one that paid for the new engine and putting strain on a new engine with mods my be risky, along with voiding the warranty.


BTW: Engine kinda blew outta nowhere. Just driving down the road, gave it a lil gas (not much at all) and BOOM. Could be crankwalking but ill probably never know.

 

[DSMJim]

When you say blew what happened exactly? If its a bad air fuel mixture then you will melt a piston and probablly burn coolant out the exhaust resulting in a James Bond type smoke screen.

Did you launch a rod through the block? That usually from too much HP but just having a boost controller will not do that. Your motor can take 400whp on completly stock internals.

Did the motor just eventually die and not start again and you really don't know what happened? Thats crankwalk.

Give me some more details and I may be able to tell you what happened. If you don't know what did it then it's likely crankwalk that killed your motor and your aftermarket parts didn't have anything to do with it. If a motor is going to crankwalk it will crankwalk no matter what. Many completly stock cars get crankwalk for no reason.

 

[nine5raptor]

Did you check the timing belt?

Plenty of water/oil in the motor?

 

[dsmturboawd]

Originally posted by Travis_GST
BTW: Engine kinda blew outta nowhere. Just driving down the road, gave it a lil gas (not much at all) and BOOM. Could be crankwalking but ill probably never know.

could be a few things. this is one of those "impossible to tell over the internet" kinda things. btw, cw has NOTHING to do with this.

 

[Travis_GST]

Sorry didnt give very much detail

It had plenty of fresh oil i just changed like 3 weeks before. I also took it to the track and ran it like 3 times about 3 weeks before it happened also, but i doubt it had anything to do with it. I do know a rod went through the block, but dont know too much more than that, untill the new engine gets put in and we can break apart the old one. With those mods it certainly shouldnt be from too much HP. Like i say i was just going down the road, i pushed the gas a bit and it started hesitating (i thought it was boost creeping again)...so i get down the road a bit and try pushing the gas again and thats went it blew. The shop its at did get it started again, but of course it sounds like crap.

 

[dsmturboawd]

Originally posted by Travis_GST
I do know a rod went through the block

who tuned the car? im sure that was the problem.

 

[brads]

Originally posted by Travis_GST
Im trying to figure out why my engine blew and if maybe it was getting too much air in the air/fuel mixture. With the performance upgrades I had, upper/lower piping, K&N Intake, electric exhaust cutout and boost controller (although not turned on) my dad thinks it was getting too much air. I tried telling him that with the boost controller turned off, its getting the same amount of boost air that it does if it was stock, thus the fuel/air mixture should be the same. Does that sound right?

Neither of those sound right. It might get more boost from the other mods. BUT, the DSM has a mass air flow sensor in it. So the more air the engine takes in, the more fuel is added. So if you did something that resulted in more air going in, you'd have more fuel going in too. At least you would if your car was working properly. If you screwed around with it when tuning it, there are several ways you could have messed up that relationship between the air flow and fuel delivery.

What did your fuel trims look like when you logged it?

Brad

 

[RipperXX]

Well if I rod breaks and it's not due to high HP which it wasn't since you were at stock boost and not heavily moded.


Had to be from MAJOR knock.. im talking a shit load here. Which means a very bad job at tuneing.. probly either had something to do with your timeing or it was just runing to lean.


Good luck with the new engine.. and actuly after you put say 3,000 miles on it, eh slap some upgreads back on her, get it TUNED WELL this time and should be all gravy..

 

[1fast97gsx]

yea I'm guessing you were running VERY lean

 

[RDS]

Originally posted by Travis_GST
I do know a rod went through the block, but dont know too much more than that

Well thats the problem obviously.....

Then this comment, now you sure about that?

Originally posted by Travis_GST
The shop its at did get it started again, but of course it sounds like crap.

Ive never known anyone start a car where a rod has gone through the block............

 

[Travis_GST]

Well i know they said the block was cracked by the rod. And they said they got it started. So...

The AFC hadn't been tuned at all...it was just monitoring some things, thats it. I was waiting to put another mod on there before i got it tuned. The AFC does have a knock sensor, and last time i checked it (which was like 2-3 months ago it said 0). The timing belt was fine. Still confused.

Unfortuntly im going to have to sell the boost controller, AFC and QTP exhaust cutout because i dont want to risk it blowing again and voiding the 3 year warranty. :thumbdown

 

[1fast97gsx]

the knock sensor on the safc won't work on a 2g .. you were running too lean and probably threw a rod.

 

[dsmturboawd]

he was using the knock feature on the safc? *smacks forehead* do you have a pocketlogger/etc or were you just blindly pushing buttons on the safc?

 

[robw22]

I noticed you have an electric exhuast cutout. By any chance do you use it regularly? or while it happened? With a stock t25 and the cutout open, there is a potential for serious boost creep which could have caused it to run really lean.

 

[Travis_GST]

dsmturboawd....Again the AFC was not tuned...it was only monitoring what it monitors. I didnt do anything to it besides set the number of cylinders and put it on karman.

It was boost creeping pretty bad when the exhaust cutout was open (at least what i thought was boost creep...hesitating big time when i was flooring it). I put the boost controller on and it stopped the hesitating (boost creep), so...

And the cutout wasnt even put on before the cat, it was after it (because theres not real straight exhaust pipe to use that cutout in before the cat....so it really wasnt doing that much besides eliminating the muffler. Should be no different than putting on a catback exhaust system.

 

[robw22]

boost creep may have caused fuel cut. I'm not sure how 2G's work with fuel cut,but It could have caused an extremely lean situation though. Also a dump after the cat is different than a cat back. The reason people do catbacks first is because the further the exhaust gases get, the cooler they get, requiring for space. So there might be a major difference. Some guys even use the silencer on their mufflers to help minimize boost creep. As for the afc, I don't know if not setting the throttle settings or ne points could screw anything up. Since your MAF signal is now going through it, it may be possible.

 

[boostnbuds]

what kind of fuel are u running?

 

[raped]

there is no way you put a connecting rod through the side of the block then started the car again. Sounds like you may have burned an exhaust valve.

 

[truwarrior]

How often are dity or faulty injectors causes of engine failures?

 

[Travis_GST]

I was running premium gas of course

raped...thats what the shop said. I know when it broke there was a bit of oil in a couple different spots on the ground, which would certainly be from a cracked block...and the shop would have no reason to lie about starting the car.

I'll know more today though...im about to go up there and take the head off to send it back to the company we bought the engine from for $200.

 

[raped]

Well then I have no clue what went wrong but if you do find out please post. Good luck

 

[awdEAGLEtsi]

i think with something like that, it would be the timing belt. nothing else really fits. cars don't run THAT LEAN to break anything in the engine, when they are running stock boost. unless a sensor went...even though i doubt that, cause the comp usually changes to a safety type mode, when the sensors screw up. but i bet it was the timing belt or something like that...seems like the if it was though the garage would have said so by now...so i don't know, but that sounds most logical.

 

[Travis_GST]

Naw, the shop said the timing belt was fine.

Well i just got back from the shop and took a good look at the engine and took off the head. It definately wasnt running lean...it was actually running rich. The top of the pistons were pretty dark. Block was cracked in a few different places. The far left piston was just demolished and bent inside the cylinder wall. I'll have pictures of it and all the other stuff soon, but it was pretty bad. Only half the piston head was left and the connecting rod and the rest of it was just about desinagrated sitting on the bottom of the oil pan. The shop said they'd never seen something that bad before.

Pics soon to come