Tony Stewart's EFI issue

dpkimmel2001

dpkimmel2001

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For all of you EFI techies out there, I saw this today.....

Tony Stewart falls victim to circuit breaker in fuel-injection system

AVONDALE, Ariz. – When a circuit breaker flips in one’s house, it takes a few minutes to figure out why the appliance won’t work and flip the switch. No problem.
When a circuit breaker goes out in a race car where every second counts, just the minute it takes to diagnose the issue is a big problem.
Tony Stewart found out just how big in the Subway Fresh Fit 500 on Sunday at Phoenix International Raceway.
A circuit breaker that is part of the new electronic fuel injection system had flipped at some point during the race, so when Stewart shut off the motor to coast under caution – just as he did last week at Daytona – the car wouldn’t restart.
He lost a lap as he needed a push to pit road and then lost another lap before the team diagnosed the problem.
“It’s not really my department,” said Stewart, who finished two laps down in 22nd. “I just turned the [ignition] switch back on and it never re-fired.
“I don’t know why that was, but it definitely cost us a good day.”
Other drivers have had similar problems in the last couple of weeks as teams learn the quirks of the new electronic fuel-injection systems used in Sprint Cup this season.
Kurt Busch, who, like Stewart has a Hendrick Motorsports engine, had an issue in practice Friday.
“You’ve got circuits in there and it’s all for sensors and things like that and if it pops that breaker, you’re done, it won’t fire back up,” Stewart crew chief Steve Addington said. “[The engine guys] are scratching their heads.
“They weren’t looking for that to happen. It’s just unfortunate it happened to us.”
Addington said the team was not sure when the circuit breaker cut off because the problem occurred the first time Stewart shut off the engine, a common practice by those trying to save fuel in order to stretch fuel mileage.
“We’ll look through the data and see when it happened,” Addington said. “That was the first time he shut the engine off to save fuel and it wouldn’t fire back up. So we were dead in the water.”
The breaker isn’t needed when the engine is running.
“You don’t have any way of knowing that it has kicked off during racing conditions,” Addington said. “It’s not what we wanted. We felt like we had a decent race car and would have gotten a top-five out of it, but that’s the way it goes.”
The circuit breaker issue likely will be looked into by all teams.
“We’ll look at that when we get back,” said Denny Hamlin crew chief Darian Grubb. “I feel like we have a really good understanding and even the [engine-building] TRD guys – we had some issues here at the race track this weekend and they did a great job informing us what was going on.”
Grubb added that “hopefully those things won’t come back to bite us” as he could see how big a bite it took out of Stewart.
“We’ve got to dig into it and see what caused it, when it happened and things like that,” Addington said. “We’re all learning through this process. … We’re going to have some unexpected things happen with this system.”
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From here.
 
Anytime you add more electrical components/wiring/connectors etc you increase the risk of failure. KISS rule in effect. Shame it happened during a race instead of testing or practice. Tony was having a good run too.
 
Remember when they added the kill switch to the steering wheel? It took a win away from someone , can't remember who, but it has been a non issue ever since.
 
ted@economy said:
Remember when they added the kill switch to the steering wheel? It took a win away from someone , can't remember who, but it has been a non issue ever since.
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Yep, I don't remember who it was though? There for awhile several drivers inadvertently hit the kill switch and had trouble restarting till they realized what had happened, I imagine it's one of the first things they check now.
 
FlFlash said:
Yep, I don't remember who it was though? There for awhile several drivers inadvertently hit the kill switch and had trouble restarting till they realized what had happened, I imagine it's one of the first things they check now.
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We both have bad memories. Hope you remember to clean your pool soon , that is UGLY.
 
ted@economy said:
Remember when they added the kill switch to the steering wheel? It took a win away from someone , can't remember who, but it has been a non issue ever since.
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Newman @ Darlington was one but I believe it happened to others as well.
 
A circuit breaker is nothing more than a fancy resettable fuse. Blow the breaker (fuse) no power to the device. Now a relay is a whole other animal. In the very simplest terms it takes a higher voltage to energize then it passes on a lower voltage to the device. As long as the device is in use it'll continue to pass along the voltage. Shut down and the relay needs the higher voltage to reset and work again. As I said a very,very extremely basic simple explaination.

But why wasn't this wasn't found out in pre race testing..???????????
 
Kinda sounded like Edwards had the same problem.By his post race interview.
 
SST55 said:
But why wasn't this wasn't found out in pre race testing..???????????
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Apparently it was. A few teams were talking about it during Daytona testing. I guess some CC's made their drivers and crew aware of the breaker, some didn't.

What I can't understand is Mclaren designing such a clumsy system. If they knew the system could get spiked during normal operation, why not put a voltage regulator in the circuit.

My other question is what documentation did Mclaren provide to teams? Not Red flagging such an important feature seems very sloppy indeed.
 
I found it interesting as I follow Earnhardt Jr. on the scanner each race. At a point later in the race yesterday, like Daytona, his crew chief asked him to start saving fuel. I was watching his in-car camera on DirecTV's HotPass channel and could see him turning the motor off and then dropping the clutch to refire the engine over and over under caution. Later when Stewart ran into the issue that he did, Earnhardt's crew chief came across telling him to stop until they could figure out what happened to Stewart.
 
dpkimmel2001 said:
I found it interesting as I follow Earnhardt Jr. on the scanner each race. At a point later in the race yesterday, like Daytona, his crew chief asked him to start saving fuel. I was watching his in-car camera on DirecTV's HotPass channel and could see him turning the motor off and then dropping the clutch to refire the engine over and over under caution. Later when Stewart ran into the issue that he did, Earnhardt's crew chief came across telling him to stop until they could figure out what happened to Stewart.
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Interesting as always dp..but I'm sure your wife tells you that every day.:D
 
dpkimmel2001 said:
I found it interesting as I follow Earnhardt Jr. on the scanner each race. At a point later in the race yesterday, like Daytona, his crew chief asked him to start saving fuel. I was watching his in-car camera on DirecTV's HotPass channel and could see him turning the motor off and then dropping the clutch to refire the engine over and over under caution. Later when Stewart ran into the issue that he did, Earnhardt's crew chief came across telling him to stop until they could figure out what happened to Stewart.
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Could it be that hot starter motors are spiking the system?
 
I am just glad that the Gestapos disciplined Brad K for not sweet tweeting about EFI last year.
 
FenderBumper said:
Apparently it was. A few teams were talking about it during Daytona testing. I guess some CC's made their drivers and crew aware of the breaker, some didn't.

What I can't understand is Mclaren designing such a clumsy system. If they knew the system could get spiked during normal operation, why not put a voltage regulator in the circuit.

My other question is what documentation did Mclaren provide to teams? Not Red flagging such an important feature seems very sloppy indeed.
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Im betting that Mclaren didn't see this "fuel saving tactic" when they designed and sold the system to nascar.

To the English, this is not a proper racing technique.
 
Apparently the problem isn't just limited to Stewart. Mark Martin also had similar issues last weekend with the new system.....

Circuit breaker issues for Mark Martin, Tony Stewart could be durability problem

While some Toyota and Chevrolet drivers had issues with circuit breakers at Phoenix International Raceway, it might seem as if the Ford camp might breathe a sigh of relief that its teams didn’t suffer from similar gremlins associated with NASCAR’s new fuel injection systems.
But that’s not the case for one simple reason: It’s too early in the fuel injection rollout for anyone to feel totally confident in the system.
The 312-lap race was the first for a non-restricted engine, and the race had its share of engine issues – from the circuit breakers flipping off for Tony Stewart and Mark Martin to the valve-train issue of Marcos Ambrose and an apparent broken valve or valve spring for Jeff Burton.
Martin’s relay box with the circuit breakers showed broken parts that indicated a vibration must have caused the circuit breaker to flip, said Toyota Racing Development President Lee White in a phone interview Tuesday. He said the breakers are set to flip at 5 amps of electrical current and they are drawing under 100 milliamps.
TRD provides engines to Michael Waltrip Racing and Joe Gibbs Racing.
“Our feeling at this point is that it is probably endemic to how the individual teams mount it, so it’s vibration related,” White said. “We are not even close to the overload electrically. We are miles away from that. … In our particular case, all of our issues were with the Waltrip side.
“We had zero issues with the JGR side. In doing some investigation, there are some subtle differences in how they mount the box.”
Hendrick Motorsports declined to comment on its investigation into the circuit breaker issues of Stewart and Kurt Busch, who had a problem in practice. Both teams utilize Hendrick engines.
The aluminum relay boxes – which provide power to the fuel pumps, injectors and the electronic control unit – contain two circuit breakers. The circuit breakers and relay boxes are not part of the NASCAR-mandated pieces that teams must buy from specific vendors, but most buy them from McLaren because it’s easier since McLaren makes the electronic control unit.
Engine builders have worried about durability throughout the process of moving to EFI because a Sprint Cup engine and car endure a tremendous amount of punishment during the course of a race.
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Full story here.
 
Bucky Badger said:
I would be happy if, with the new system, you couldn't be sure the car would refire. It would make people get fuel to RACE to the end.
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I don't know. They push the limit now knowing that they may run out of fuel. I don't think that will ever change.

As long as fuel's involved, there will always be fuel mileage races. The one and only way to eliminate it is for NASCAR to throw a competition caution near the end that requires them to dump a can of fuel in there. I don't think any fan wants that. Correction..... There will always be someone. Personally though, I don't really have a problem with a fuel mileage race. It's all part of the strategy. Teams work hard to gain an advantage, whether it be aero, mileage, whatever.
 
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