Legus

So I bought an LS460 a few weeks ago. It was sold to me with a "custom exhaust". This "custom exhaust" is a simple bolt on straight pipe. It sounds fantastic no complaints. When I first got it, I never really hit the gas at all, but I would notice a muffled popping/backfire noise from the exhaust. I have gradually been driving the car harder as I get used it performing so well now. I now notice this popping noise all the time, I hit the gas hard and then let off (NYC traffic) and it BANGS. My mechanic (and a few of my car friends) said its not really supposed to be like that if the previous owner really only deleted the muffler. Yesterday I got a check engine light, scanned it, the engine is running lean. My guy might've even figured it out by now as I didn't talk to him for a while, but I would love to hear anyone else's input

VanCityLS4

iTrader: (1)

Legus

Ill send pictures when its up on the lift in 2 days. I told him to check my catalytic converters when he's working on it. Thanks. I hope this isn't it because I was very clear when I asked the original seller if the catalytic converters were removed and he said no. This would have to become a legal matter at that point as I do not want to drive with emissions violations. My mechanic drove it over a hundred miles so far, as he is a close friend of mine and he keeps the car days at a time so he can work on it before/after hours at his shop, so I do not think it could be loose without him noticing.
Maybe they just can't believe it sounds so amazing and so loud with just the muffler gone, none of them had ever heard a straight piped V8 before.
The check engine light is intermittent only came on the day after I got the car for a few minutes and then this one last time when he was driving it. Hasn't happened again. He said if its that rare for it to come on its probably a tiny air leak somewhere along the lines, which he will be checking for over the next couple days.

MobbinVIP

iTrader: (16)

Video clip with revving & the pops & bangs?

sktn77a

iTrader: (2)

Is it a mechanical "knocking" or an explosive "bang" (like an exhaust backfire).

Oliver Enterprises

It could be running lean possibly due to bad O2 sensor(s). Or it could be that it needs the extra back pressure of the mufflers to run the way it was tuned from the factory. Generally popping and cracking in the exhaust represents cool air entering the exhaust pipe mixing with hot exhaust. Which generally means there's a leak in the exhaust, maybe somewhat close to the engine. Do you know how close to the engine the custom exhaust exists?


Jason Oliver

Legus

Thanks for all the input guys, I do appreciate it, I just moved beginning of this month so I haven't had any free time to visit here. Its been a long time huh. Well I know my cats are fully intact (yay). My guy checked the exhaust system up and down it was fine. Either way just the other week I got tired of cops following me around (I live in NYC, big ticket for this) so I put the mufflers back on. You were correct when you said it needed the extra back pressure of the stock mufflers. Still might need an 02 sensor or I think he said a camshaft phaser? But the light has not come on since so that is to be decided in the future.