Fill A SRX 2.8T With 87 And...

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24,444
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CA
It goes boom.
Quote:
Gunnar Heinrich, editor of AutomobilesDeluxe, recently mistakenly filled a press fleet Cadillac SRX Turbo with regular unleaded fuel. The result? A catastrophic "mega knock event." His semi-harrowing tale of sudden unintended highway deceleration below. — Ed. IT'S nighttime and I'm rather unnerved. I'm on the 101 halfway up some mountain outside Ventura, California in a 2010 Cadillac SRX Turbo that has just died in the narrow meridian. I'm barking at some nonplussed 9-1-1 dispatcher on the cell, OnStar's on hold, and I'm ready to jump the jersey barrier if some dazed motorist drifts my way. They all seem to brush by at light's speed. This broken press car is one of Cadillac's latest midsize crossovers – a plush, Lexus RX fighter – that had just lapped its two thousandth mile before the car's engine bought the farm. In no time at all I had dropped from a comfy 65 mph cruise into a sputtering stop with black smoke billowing from beneath the silver hood and a long oily trail in my wake. And now I'm awaiting rescue. Minutes tick by endlessly. But the state police do arrive. The officer spies my precarious position and proceeds to snake his patrol car back and forth across the freeway- side-winder style. Only then, does traffic slow to a grudging halt. "If you can start your car, move it across to the right side." The officer coolly broadcasts over the loudspeaker. Now, all of Ventura seems to be waiting behind him. The cars are like greyhounds at the gate and I feel like the rabbit as – rattled and frozen – I climb behind the Caddy's helm and press the start button. Thunk-Thunk-Thunk-Thunk-Thunk-Thunk goes the mortally wounded motor. Into drive. We're on borrowed seconds! The SRX c-r-a-w-l-s across the freeway to the far side. The go pedal's level with the carpet. I reach the right side and the Caddy quits. Traffic resumes its F1 pace, a discussion with the officer ensues, and ten minutes later the tow truck shows. The driver shakes his head and says that only days prior some poor guy had similar trouble with his bike. When he tried crossing to the breakdown lane he got hit in roughly the same spot where I'd landed. He died. So, what caused this fresh new Caddy to breakdown? The answer arrived yesterday afternoon in a conference call with GM. Their findings are triggering a model-wide update to go into effect directly. DAMAGE REPORT On the phone is Tom Sutter. Mr. Sutter is GM's chief engineer for the automaker's V6 engines. Also on the line is David Caldwell, Cadillac's press manager. Mr. Sutter leads headlong into a thorough explanation of the wheels that were set in motion following the incident. "We took this very seriously," he says. His tone is direct and earnest. "As soon as it happened, we expedited the vehicle's shipment back to our test center in Warren, Michigan. We've been at this 24 hours a day, 7 days a week." He and his team "tore down" the motor, analyzed the car's black box data, and sent a fuel sample to a third party lab for analysis. Additional tests on a dyno replicated the failure, but they've yet to duplicate the incident in real life testing. The SRX Turbo uses a 2.8 liter, 300 hp V6. This same engine has served for five years in Saabs including the upcoming 9-4X. The engine also powers Germany's Opel Insignia. THE BREAKDOWN Mr. Sutter is describing my incident as a "Mega knock event." "We have a high degree of confidence that we've sourced the problem," he tells me, getting down into the gory details. What happened is as follows and was, apparently, a fluke: The V6 in the Cadillac requires a minimum 91 Octane. Lab tests had shown that the SRX was running on regular which meant that yours had inadvertently fed the car 88 Octane gas and not the factory mandated premium. At some point during travel, between 2000-2500 rpm – or normal highway cruising speed – the engine's management system had adjusted the air fuel mixture to work too lean causing a retarded spark – but crucially – it allowed for a simultaneous turbo boost which led to a catastrophic pressure build up in the cylinder chambers. This caused cylinder six to fail quickly -leaving yours stranded. Mr. Sutter's team concluded that the resulting pressure in the chamber was four times greater than the stress during full throttle acceleration. "We've been working on a new calibration which should be implemented in coming days," he says, indicating that this will ensure proper engine management going forward during what we might describe as "lean times" during the fuel consumption of a given SRX Turbo. Mr. Caldwell stresses that what happened was an extremely rare event and that they've had only a couple of incidents that resemble what happened to me in California. He suggests that the low Octane gas could be considered a contributing factor and not the primary cause of the engine's failure. But not everyone is careful with their choice of gas (as evidenced by this writer) and high Octane gas isn't always available in some rural areas. Surely the car must be engineered to compensate? Both acknowledge this aspect and say that the SRX's management system should have adjusted to accommodate for the lesser grade petrol and their system fix will ensure that it does going forward. Nevertheless, Mr. Sutter maintains that the low Octane gas was the primary trigger in my car's failure. "Ever since we've switched to low displacement, turbocharged engines, we've noticed a sensitivity [to Octane levels]." The 2.8 liter, turbocharged V6 was created at GM's Pontiac, Michigan center in tandem with Saab staff in Sweden who engineered the turbo. While most Saabs require only regular unleaded, the Cadillac SRX Turbo's V6 represents the highest output version of this particular powerplant, hence the requirement for higher grade fuel. NEXT STEPS As this article posts, GM is conducting field tests on six SRX Turbos in Death Valley to ensure that the recalibration they've devised will prevent a repeat of the failure when the vehicle runs on regular unleaded. Once finalized, Cadillac will implement the engine management adjustments to the SRX assembly line so that new SRX Turbo units rolling off the line going forward will benefit from the update. Current SRX Turbo customers will receive the update at their Cadillac dealer during service, though the company has not yet decided how it will inform customers on the need to getting their car updated. We should receive word on their customer plan within the week. Also, GM will provide Automobiles De Luxe with another press car to complete our review. Expect our full take on the 2010 Cadillac SRX Turbo next month. Here's hoping for a smoother road test.
http://jalopnik.com/5501161/never-fill-a-cadillac-srx-turbo-with-regular-unleaded-gas I must say, it is pretty pathetic for a modern turbo car to not be able to run on 87 for even a short period of time without self-destructing.
 
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36,645
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ME
I may be way off base but I smell drive-by-wire shenanigans. IE a wider throttle for better MPG and other trickery to make it feel normal to the driver who was just cruising along. This is probably one of those turbos they're trying to make feel like a normal engine, or even an electric motor. Linear power, except when it isn't.
 
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10,060
Location
Central Washington
I think thats what it was doing. Trying to stay in that semi-diesel state. Since it waited to go up the mountain and then failed quite spectacularly, I think it was fine until he needed more power to go up the mountain. Then it tried to stay lean burn while allowing boost.
 
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10,008
Location
Upstate NY
That event happened a while ago. I believe GM tore down that engine and sent 6 others out to be tested in the same manner to replicate the failure, and so their engineers could tweak the computer settings a bit.
 
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3,756
Location
CA
Originally Posted By: Shannow
Or a modern high tech engine not run for more than 3,000 miles on a modern engine oil ?
Mileage and oil choice don't make a bit of difference when it detonates as badly as it sounds like it did. It was a software problem that caused the failure. I've done the same thing to my car. Live and learn.
 
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11,196
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NY Capital District
Originally Posted By: BuickGN
Originally Posted By: Shannow
Or a modern high tech engine not run for more than 3,000 miles on a modern engine oil ?
Mileage and oil choice don't make a bit of difference when it detonates as badly as it sounds like it did. It was a software problem that caused the failure. I've done the same thing to my car. Live and learn.
Holy cow look who it is! :O
 
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8,756
Location
RI
No knock sensor? Did GM not suspect that the numerous ignorant consumers wouldn't make the same mistake? Who the @*(# is doing the testing at this bailed out automaker? Fire his ^&%. Nope, fire the entire R&D and engineering team and start from scratch. And, what can I say about so-called "automotive" writers??? They write but many are clueless about machines in general. Almost a Darwin award, maybe next time!
 
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10,060
Location
Central Washington
I suspect it happened too fast for the knock sensor to adjust, there was not enough lee way in the programming for it to make enough of a difference or a combo of both. Remember, combustion pressures were 4 times higher than full throttle accel, things start breaking real fast.
 
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3,756
Location
CA
The problem is once the knock starts it's hard to stop it just from timing retard. Knock sensors, especially on turbo cars are only there to give you a little time to react, not save the engine if something goes terribly wrong. What it sounds like happened was: 1- It leaned out causing the knock sensor to tell it to pull timing. 2- Mechanically brought in more boost due to the retarded timing (yes, this is a very real thing in a turbo car). 3- More boost brought more timing retard and so on. Power may have stayed more or less the same since timing was so retarded but the boost was up and the driver may have been unaware any of this was going on. They need to program the DBW to pull throttle along with the knock retard and a richer mixture. Or use an actual sensor in the tank to determine octane and go to a completely different map.
 
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7,256
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USA
Originally Posted By: L_Sludger
Yet another argument for us motorists to fill up the tank with the good stuff.
Only if your car requires premium. It is great this happened with an auto journalist vs owner. Do you really think GM would have done this much investigation on such a failure with a single vehicle.
 
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43,676
Location
'Stralia
Originally Posted By: BuickGN
Originally Posted By: Shannow
Or a modern high tech engine not run for more than 3,000 miles on a modern engine oil ?
Mileage and oil choice don't make a bit of difference when it detonates as badly as it sounds like it did. It was a software problem that caused the failure. I've done the same thing to my car. Live and learn.
Was including another post where technology and DI was dictating a 3,000 mile OCI as an improvement in technology in my reply. One is a manufacturing defect, while the other is the consumer's price of adopting new tech. Pick which is which.
 
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1,006
Location
Montreal, Quebec in Canada
Originally Posted By: rjundi
Originally Posted By: L_Sludger
Yet another argument for us motorists to fill up the tank with the good stuff.
Only if your car requires premium. It is great this happened with an auto journalist vs owner. Do you really think GM would have done this much investigation on such a failure with a single vehicle.
I would think the response would have been the same: With a car with so few mileage, every engineer would have wanted to get a hand on this engine to understand what happened. To release what they found out, it is another story. That is why it is great that happened to a journalist.
 
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