driving behind a new Caddy last night...

[dwcopple]

not sure what model but I think it was a CTS. Found it strange that it only had one exhaust outlet on the driver side with no chrome tip either, but anyways. He stepped on it to gather speed to fit in between two cars in the right lane and this huge puff of nasty smelling black smoke shoots out of the exhaust and the car sounds awful. A few seconds later, he did it again and the same result happened. [censored]? Is this a DI car? is this what happens? Very weird...

 

[NateDN10]

How old would you say it was? The Northstar powered Caddies are known for developing carbon deposits if not driven hard frequently. Then once the driver does use the gas, a bunch of that carbon gets burnt up in a cloud of black smoke. I've also seen this when someone floors a DI engine that wasn't warmed up yet.

 

[ProfPS]

Could be an aftermarket exhaust and the owner didn't want to pay the extra $ for the OE dual exhaust system. If this is the case, it's chocking the heck out of the engine and could be the reason for the periodic accelerations.

 

[Hokiefyd]

Some of the newer base-model CTSes have single-outlet exhausts with no tip. He was probably working a cold engine over hard. A Northstar-powered Cadillac would've had dual tips.

 

[rshaw125]

The CTS models I have seen lately either had duel exhaust (sedan) or a center 'dual' exhaust on the coupe.This is with the 3.6 direct injection engine. Which is the base engine I thought.

 

[cchase]

Most vehicles will blow black smoke on WOT. It's a function of rich fuel tuning.

 

[Hokiefyd]

The CTS was available for a while with a 3.0L V-6 engine, the 270-hp LF1. http://en.wikipedia.org/wiki/GM_High_Feature_engine#LF1 My brother has this engine in his CTS, and reports that it's not nearly as fast as 270 hp would have you believe. The torque peak is 223 lb*ft at 5,700 rpm! That's one high-revvin' engine.

 

[CivicFan]

Originally Posted By: cchase

Most vehicles will blow black smoke on WOT. It's a function of rich fuel tuning.

That's my understanding as well - nothing wrong with this particular Cadillac. The driver doesn't normally see this as it happens behind them and they are more focused on the obstacles ahead of them.

 

[dwcopple]

it was a newer one, the newest body style CTS or STS. It was a stock muffler with no tip, as I could see the "wrinkles" in the huge stock muffler. The rear bumper cover had two mesh screen sections in the lower center and the tip cut-out was on the driver side. I can't find a pic of one similar online though...weird. If that was normal, that is ridiculous. The cloud was huge and the smell was disgusting. I guessed it was a fueling issue. Maybe not though huh?

 

[OVERKILL]

Originally Posted By: dwcopple

it was a newer one, the newest body style CTS or STS. It was a stock muffler with no tip, as I could see the "wrinkles" in the huge stock muffler. The rear bumper cover had two mesh screen sections in the lower center and the tip cut-out was on the driver side. I can't find a pic of one similar online though...weird. If that was normal, that is ridiculous. The cloud was huge and the smell was disgusting. I guessed it was a fueling issue. Maybe not though huh?

Like this: ?

 

[swirlparanoid]

saw a new Porsche Boxer do that the other day pulling out of a parkinglot, (was probably still cold) the driver punched it to get in front of me and a comical amount of black smoke came from it at first, eventually stopped though

 

[dwcopple]

Originally Posted By: OVERK1LL

?

Bingo!

 

[kkreit01]

I've never had a new car that smoked, and I've had a lot of them. This -- I would not like.

 

[cchase]

Originally Posted By: kkreit01

I've never had a new car that smoked, and I've had a lot of them. This -- I would not like.

I'd bet you good money they blow a puff of smoke on WOT, especially cold. Drivers don't see it.

 

[dwcopple]

The stretch of highway we were on, there was no way the engine was cold. We hadn't had a stop in miles.

 

[Colt45ws]

Yeah, the 3.0L generally comes with single exhaust. There is an option of some sort to get duals with the 3.0L, though. My Grandpa's is setup that way.

 

[cchase]

Originally Posted By: dwcopple

The stretch of highway we were on, there was no way the engine was cold. We hadn't had a stop in miles.

It really doesn't matter. Is this thread some excuse to get something out? Because as has been mentioned previously, just about every stock tuned car will do this under WOT. It's not abnormal nor does it indicate a problem.

 

[Colt45ws]

Yeah, stock tunes tund to go really rich at WOT. I seen a dyno sheet from a Town Car and it was going 8:1.

 

[dwcopple]

Originally Posted By: cchase

It really doesn't matter. Is this thread some excuse to get something out? Because as has been mentioned previously, just about every stock tuned car will do this under WOT. It's not abnormal nor does it indicate a problem.

Yep, it's an excuse to "get something out". The $50K dollar car appeared to be a P.O.S. under heavy acceleration, and I choked on its fumes...

 

[KrisZ]

Originally Posted By: cchase

Originally Posted By: dwcopple

The stretch of highway we were on, there was no way the engine was cold. We hadn't had a stop in miles.

It really doesn't matter. Is this thread some excuse to get something out? Because as has been mentioned previously, just about every stock tuned car will do this under WOT. It's not abnormal nor does it indicate a problem.

Perhaps it's normal for this particular engine, and it is normal on turbocharged engines, but to say that all NA engines do it, is a bit of a stretch. From OPs description the black smoke was excessive, a little black puff of smoke would be OK, but a big cloud that choked the driver behind is definitely not normal. Having said that, balck smoke is not such a big deal, blue on the other hand...