mighted1987

This is pretty weird, im still waiting for my uncle to check my car during the
Month, but i dont understand if there is a cylinder with bad compression and the leak down test gave no good new, how can i still drive this car with some good power still, the car is back to stock cams but
When i start it for the first 25 second it sound a bit like my hot rod, prolly cold engine higher revolution, then the rev settle and you can hear massive "pow" from the exaust, could a valve exaust give bad compression to a cylinder and reduce engine power? Lemme me know what you think

when the car get hot, the noise stop..car drive like usual....

BigDinTexas

Aren't you supposed to be getting a new engine? If so, why are you still driving this one? Or are you still trying to figure out what is wrong with this one?

I can't help, but I'm curious. You seem more and more upset about owning this particular car in your posts, mostly because of the engine failure after the dyno.

Don

mighted1987

in theory, but im afraid of the delay, i mean like, if this probleme can be something not too big, id prefer keeping this forged engine and keep the higher boost and pulley instead of a stock engine with low boost blower.. i know im getting pretty upset and annoying with this story, sorry...im just clueless and useless at this moment, i just wanna enjoy the summer with my new purchase, get thing fixed, i cant sell it..cant really drive it, and how much time will it take to get either the engine fixed, or swap another engine...i just dont know when he will have the time, he only got one mechanic guy at his business, and they sell like 4-5 mustang per week and truck that need to get stuff done before delivery, it easily a day of work at his cost to get my engine removed etc, maybe more, what he say and what/when he can do is really two thing. btw: i only drove it back home from the dyno ( 1 hour route, strangly, i never got the orange wrench probleme, car didnt choked or anything, the tune he made was better of course, he changed sparkplug and a candle in a cylinder)...the tuner told me: im clueless about whats going on your engine, id say tell your uncle to check for valve etc before removing the whole engine, could be a valve exaust or something)..im not sure at which point does the probleme in cylinder 6 affect the whole car, i mean, might be a month i was driving with this issue, that why it was getting worst to worst (toasted a sparkplug and a candle)...

moosestang

There are any number of things that can cause low compression in 1 cylinder. Sticking valves, burned valves, bent valves, bad rings, cracked piston, broken valve springs, etc.

All that popping is coming from your exhaust on a cold start? That could be the unburnt fuel from cylinder 6 burning in the exhaust, but I wouldn't think so if the engine was just started. It doesn't sound good.

I don't think you'll find the answer on the internet though. You need someone that knows what the F they are doing and that's not the mechanic you took it to and clearly not your uncle.

I think your motor is completely stock and the previous owner was full of it. You can't trust someone that would put lambo doors on a mustang. It's not like you're running 16 lbs of boost. I've been pushing 10psi for 5 years.

mighted1987

''I think your motor is completely stock and the previous owner was full of it. You can't trust someone that would put lambo doors on a mustang. ''
lmfao, that made me laugh

yah you sound like you know alot on these car moose, your running 10 lbs on stock engine?

my m90 is pushing exactly 9.4 lbs, think i could leave that custom crank pulley on a stock block and still doing fine?(we're talking if still get that other stock 4.6 block)

what would you suggest me to stay safe and still get some good power out of the car.
wish i was in the states for that, definitly more accessibility and people that know what they talking about.

i feel like a headless chicken running around in every town for help on my car but always getting sucked a fews hundred bucks outta me and at the end, I still got no logical solution to my probleme, just less money in my pockets.

moosestang

You can have 10psi on the stock block, assuming you have a good tune and at least 91 oct up there.

If you do get a new motor, or figure out what's wrong with yours, you might consider an email tune from one of the online mustang tuners. It doesn't sound like you have a local tuner that knows what he's doing.

You may just have a problem with the valves on cylinder 6. You really need to do another compression test on that cylinder to verify if it's the rings or valves. Or just pull the heads, but I'd make damn sure you have a problem first.

You can pull the spark plugs yourself, see what the #6 plug looks like. You could even have a blown head gasket. Does it overheat? Hows the oil and coolant look?

moosestang

After googling it and listening to your video again, I wouldn't be surprised if you have a broken valve spring on the exhaust valve. That's why you hear all the backfiring, because the combustion is opening your exhaust vavle.

Not our motor, but similar symptoms

http://www.f150online.com/forums/v6-...ve-spring.html

I'm just being an e-mechanic now, but it fits your symptoms. I wouldn't be surprised if your mechanic caused the problem when swapping cams.

mighted1987

I'm just being an e-mechanic now, but it fits your symptoms. I wouldn't be surprised if your mechanic caused the problem when swapping cams.

**but the constant back fire stop when engine heat up?** i do get some pow pow when i down shift, but it really aint much, a few fart, i alway though it was because i had no cats and the exaust fart a bit this way...


the mechanic were talking about here is the tuner that do installation too, that ****ing moron who told me i should remove my hot rodcams cause he though it was the probleme, he say after his tune, the car was responding way better, but the car keep farting like that, he though it was cause of the cam, that why i did that useless 500$ move...
he didnt charge the tuning session cause he said he shoulda did test on the engine before everything...but the car was running horrible before i brang him, no power between 2000-4000 rpms, misfire etc, there is no heat, all coolant look o.k the guy ran a compression test, noticed the cylinder 6 had bad compression, he did a leak down and (that part im not sure how he told me it) it wasnt get to the engine, or maybe he said it was getting in the engine, but either way that mean it wasnt good. im pretty sure he changed a spark plug during the cams swap also a candle (english term no idea, the things in the cylinder)

but the damn car wasnt doing that pow pow before..he definitly ****ed something up
and for the mail tune, im not sure this is a good idea, i got told email tune for people in canada, we do not get same result with air difference.. i dont think the tune he did is bad, the car seems a bit faster then it was...just not comfortable driving it with that cylinder story on the mind..

moosestang

I'm still going off the assumption that compression is low in cylinder 6. We don't even know how low is low. I would do my own compression check. Warm up the engine completely and do a compression test on 5 and 6 cylinders.

Having no cats doesn't cause loud backfires like that. The backfires could be less after it warms up, because the computer is commanding less fuel than at startup.

zanypunk

He should do a running compression test. No assumptions :P