Engine failure

Vince@R/T

Hey Guys, my suspisuion is a cracked ringland when we first started tuning it. It was a little bit low on 93oct compared to the other 1.5 cars I've done even though he had a smaller pulley. When the motor let loose watching the data logs the knock went from -1 to -10 instantly and let loose. AFR were good and power was climbing right up till the failure.

As far as the gauge we noticed a drip coming from the gauge after the dyno sesion. At no point did it leak or spray fuel in the dyno.

jmroy6

When i got the car back fuel would pour out the top of the gauge just from the pump priming. If the afrs looked good during tuning then its prolly not the cause of this. It could have been a bad ringland, the motor was old and most definitely tired. Its been boosted since day one. Im not bashing anyone or blaming any products.. this is just part of the game

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2012 370z GTM SC

phunk

Agreed! I just care to make sure that its understood that an old leaky gauge, while it certainly needs to be addressed immediately, doesnt seem like it could realistically cost you an engine in the time-span of a single full throttle pull. Since any fuel leaking at all is too much, I am sure that a small leak looks significant to the naked eye. But if its not blasting out of there, I dont think youd have been at risk of running lean unless your fuel system was already on the edge. I think the larger concern is just the fuel leak itself, as a hazard for the entire vehicle.

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jmroy6

Yeah, i understand completely; based on the feedback from Vince, it sounds like a small fuel leak doesnt have any affect on the fuel trims anyway.

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2012 370z GTM SC

phunk

Its all completely circumstantial. Using random numbers, say you have 300lph of fuel available before pressure drops, and your engine is consuming 250lph of it, then this means you can "afford" a leak of 50lph before pressure begins to drop. Your fuel consumption with a centrifugal supercharger will climb to it's peak at redline. So the closer to redline you get, the less you can lose to a system leak before its causing an immediate problem.

So you can definitely leak enough fuel to tax your fuel system to the point of running the engine lean. Only you saw how much was leaking, so none of us can say with absolute certainty whether its enough to cause a lean condition. But I have only ever heard of these gauges dripping or oozing a little, I have not yet heard of one really letting it go in a significant way, or basically bursting mid pull.

If it is truly leaking a whole ton, I would like to get it back to the manufacturer.

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