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Quick rev before shutting off motor?

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Old Jun 29, 2006 | 08:04 AM
  #31  
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From: North NJ ---> ATL
i cant believe i actually read this.. i also why you would let your friend DRIVE youre evo the first time he rides in it but if this is what you guys come up w/ to kill time... then ...
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Old Jun 29, 2006 | 08:05 AM
  #32  
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This is silly.

My opinion: If it's not broke, don't fix it.

I'm pretty sure there are several cars on the forum that have put a insane amount of miles on their engine without doing this.

How bout you do this technique for as long as you own the car, and then post your results.

Last edited by MIevo8MR; Jun 29, 2006 at 08:08 AM.
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Old Jun 29, 2006 | 08:16 AM
  #33  
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Guys If we had carbs. on our cars this would be fine...But since we dont theres no reason. Its only to help start later. It just leaves some fuel in the intake and the gravity does the rest. Any fuel injected car dosent need this help beacuse gravity has less of an effect to a fuel inj. car . It would do more harm than good. If this would be a help to a fuel injected car the factory would set it to do so.
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Old Jun 29, 2006 | 08:19 AM
  #34  
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From: City O Sin, MA...the not so sinish part though...
Just dont do it. Like already stated, its your turbo you have to worry about. You rev it right before you shut it off and your turbo is spinning faster before oil gets cut off to it. Then it stays spinning with no lubrication. Its not worth doing it. The whole fuel in the cylinder thing is not a problem. If it were, it would suggest it in the owners manual. If you value your turbo, dont make a habbit of this.
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Old Jun 29, 2006 | 08:48 AM
  #35  
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it's funny cause sometimes mine does that on its' own. i have my TT set for 10 seconds, and on the occasion when i turn off the ignition, the engine will rev to about 2.3-3k and then get back to idle and shut off after 10 seconds. always wondered why it did that.
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Old Jun 29, 2006 | 08:56 AM
  #36  
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From: 5 sick duce lbc
this is not needed! think about those pro racers with turbo timers...do they ever rev their engines after leaving the turbo timer on? i dont think so. i only suggest you just let the engine cool off for a few sec to a min depending if you drove hard and shut it off.....no need to rev
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Old Jun 29, 2006 | 10:33 AM
  #37  
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Originally Posted by sirloin1219
it's funny cause sometimes mine does that on its' own. i have my TT set for 10 seconds, and on the occasion when i turn off the ignition, the engine will rev to about 2.3-3k and then get back to idle and shut off after 10 seconds. always wondered why it did that.


check your TPS sensor and/or wiring plug for it. you may have a loose connection on the plug or the tps sensor is acting up and you need to replace it.


little errors like that make nice cars **** if you dont tend to them. the little problems will add up and you will end up having an expensive piece of junk heh
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Old Jun 29, 2006 | 10:41 AM
  #38  
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I just talked with one of the engineers in the fuel systems group and he said for fuel injected cars it's not necessary.

On rotary engine's it is necessary in certain situations. He does it on his RX-8 only when the engine hasn't had enough time to fully warm up before shutting it off. (i.e. moving it in the driveway).

The proper way to do it is shut off the engine before it comes back down to idle.
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Old Jun 29, 2006 | 11:50 AM
  #39  
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From: Cocoa Beach FLA
i want my click back. i think i actually lost brain cells reading the thread.
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Old Jun 29, 2006 | 11:55 AM
  #40  
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From: Sconsin
Originally Posted by MIevo8MR
I just talked with one of the engineers in the fuel systems group and he said for fuel injected cars it's not necessary.

On rotary engine's it is necessary in certain situations. He does it on his RX-8 only when the engine hasn't had enough time to fully warm up before shutting it off. (i.e. moving it in the driveway).

The proper way to do it is shut off the engine before it comes back down to idle.
In the rotary you want to actually hold the revs for a few seconds and turn it off while holding the revs.
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Old Jun 29, 2006 | 12:16 PM
  #41  
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if you shut if off there is no spark, so how can fuel burn?
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Old Jun 30, 2006 | 02:44 AM
  #42  
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UGH...

IF YOU PEOPLE READ ANYTHING AT ALL, PLEASE READ EVERY WORD I SAY IN THIS POST. I DON'T THINK YOU GUYS ARE LISTENING.

First, I post this to to see what you dudes think and some people have to nothing to offer except negative worthless comments about me or my friend. Thanks; real insightful.

Second, I don't mash the throttle. A quick blip. I've already said I don't go past 1400 RPMs, if that. Please people, read.

Third, please people think about what's going on when I do this. Fuel does not instantly appear in the cylinder, it has to get there from outside the cylinder. Plus, it's in the cylinder for two strokes of the cycle before it ignites. Also when you cut the engine off, the ignition cuts of instantly. MAYBE some fuel is left over as it isn't burned since the ignition is cut off. There is a "lag" time between when fuel is injected and is ignited.

Please read the above statement. Now do it again. THIS IS WHERE I'M COMING FROM.

As for being more rich when this blip occurs, I don't think this is the case. What's the difference between normal idle and a slightly elevated "idle"? I don't think the fuel system starts to freak out and dump in fuel. I barely press the gas.

Also, I'm not going to ruin the turbo or any of that nonsense. This will have hardly any heating up of the turbo. It's a blip. It will not spool up the turbo up to any level worth noting. Also, since the motor has a MECHANICAL OIL PUMP, oil pressure will not be lost until the motor stops. Turbos are oil intensive because they spin at high speeds and in this case the turbo isn't at high speeds. The turbo is going to be fine, but I do appreciate you guy's concern though.

The comment about my suggestion about WOT during shutdown isn't well thought out. Let me put it this way: blip throttle, un-blip throttle, revs begin to fall, shut-off key, as revs continue to fall go WOT. When I go WOT the system is off, including the fuel system. This just makes it easier get air through the motor, which is why I suggested it.

Look, I'm not all hardcore about doing this. I simply wanted to get some more opinions on this. INSIGHTFUL opinions without any sort of attacks, worthless comments, etc. I'M HERE TO LEARN. Not to be a punching bag to boost your ego, because your life in the real world is unsatisfying.

Some arguements against doing this in this thread were insightful, but I can say most weren't. I'M NOT ARGUING THIS, FOR THE SAKE OF ARGUEMENT; I'm arguing this to have a discussion where many viewpoints are comming together. Thanks to anyone who took the time to read and discuss this in an intellectual fashion.

For the rest of you.

Last edited by ITEM9; Jun 30, 2006 at 02:46 AM.
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Old Jun 30, 2006 | 03:13 AM
  #43  
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Originally Posted by EVOgasmIX
...As for being more rich when this blip occurs, I don't think this is the case. What's the difference between normal idle and a slightly elevated "idle"? I don't think the fuel system starts to freak out and dump in fuel. I barely press the gas.
I believe the ECU uses MAF and TPS sensor rate-of-change thresholds to calculate the acceleration enrichment. Considering how quick the throttle response is, and how rich the car runs in closed-loop, I would imagine both thresholds are pretty low. Carbs have something similar but I forget what it is called or how it works. Anyway, I'm pretty sure what affects acceleration enrichment isn't how much you blip the throttle but rather how quickly.

Last edited by machron1; Jun 30, 2006 at 03:22 AM.
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Old Jun 30, 2006 | 10:28 AM
  #44  
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From: Spec Ops
this thread is a waste of server space
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Old Jun 30, 2006 | 11:24 AM
  #45  
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From: Portland, Oregon
Originally Posted by vboy425
this thread is a waste of server space
if that is true it's only because it is full of OT BS posts like yours...and now this one...and posts like "don't let your friend drive your car"... :
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