996 Starting while holding WOT
04-21-2017, 02:31 PM
#1
996 Starting while holding WOT
Hey guys, I was wondering if the 996, specifically a 1999, what it would do if you start the car while holding wide open throttle. On my other cars this activates a maintenance mode where it won't send spark or fuel to the cylinders. It is typically used if doing cylinder compression testing or the like. Before I try this on my 996 i want to make sure it wont go to redline from start as I think that would be bad.
As for why I want to do this, on my other cars I do this after changing the oil in order to somewhat prime the engine with oil. I would especially like to do this on the 996 since every time I change the oil the engine clatters like crazy until the chain tensioners and lifters get pressurized. If i could i rather mitigate that a bit with a few cold cranks.
Thanks in advance.
As for why I want to do this, on my other cars I do this after changing the oil in order to somewhat prime the engine with oil. I would especially like to do this on the 996 since every time I change the oil the engine clatters like crazy until the chain tensioners and lifters get pressurized. If i could i rather mitigate that a bit with a few cold cranks.
Thanks in advance.
04-21-2017, 02:38 PM
#2
at WOT it may enter flood mode. You could just start the car and shut it off as soon as it fires....do this a few times and no drama.......unless you are like the guy here that drains his oil for 2 weeks ...it may take a few more fire ups
04-21-2017, 02:50 PM
#3
Yeah I tried this once and it didn't really help. Just made it start hard twice. The way I figure it, when the starter is turning the motor over its alot less strenuous than when it finally fires up. Especially since the 996 likes to go to 2000rpm right when it fires up.
04-21-2017, 04:20 PM
#5
Rennlist Member
04-21-2017, 04:39 PM
#6
Race Director
Hey guys, I was wondering if the 996, specifically a 1999, what it would do if you start the car while holding wide open throttle. On my other cars this activates a maintenance mode where it won't send spark or fuel to the cylinders. It is typically used if doing cylinder compression testing or the like. Before I try this on my 996 i want to make sure it wont go to redline from start as I think that would be bad.
As for why I want to do this, on my other cars I do this after changing the oil in order to somewhat prime the engine with oil. I would especially like to do this on the 996 since every time I change the oil the engine clatters like crazy until the chain tensioners and lifters get pressurized. If i could i rather mitigate that a bit with a few cold cranks.
Thanks in advance.
As for why I want to do this, on my other cars I do this after changing the oil in order to somewhat prime the engine with oil. I would especially like to do this on the 996 since every time I change the oil the engine clatters like crazy until the chain tensioners and lifters get pressurized. If i could i rather mitigate that a bit with a few cold cranks.
Thanks in advance.
There's a reason the idle speed is 740 RPMs vs. something lower. And there is a reason the DME takes the cold engine up to over 1K on a cold start.
(When I start my 996 Turbo the oil pressure gage needle doesn't even hardly come off the bottom of the gage while the engine cranks. It does zoom up when the engine fires and as the RPMs climb.)
As you slow crank the engine in the meantime residual oil is being forced out of the bearings so when you do fire the engine and the RPMs climb there may not be sufficient residual oil present to form the hydrodynamic bearing (oil film) that keeps the bearing surfaces from making metal to metal contact.
The clattering noise is harmless. The engine is better off just firing the engine up normally. This gets the oil flowing the quickest.
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04-21-2017, 06:25 PM
#8
I used the start-off-start-off process this year as opposed to the pull the fuse I have used in past years and it seemed to work well. The start-off-start-off process is recommended and used by people who are much more knowledgable than I am on these cars and on newly rebuilt engines, so...if it works for them it's good for me!
No popcorn for me...Thanks!
04-21-2017, 06:34 PM
#9
Rennlist Member
Till you wear out your ignition switch prematurely...
04-27-2017, 11:48 AM
#11
Be aware that because the starter turns the engine so slowly the gear oil pump may not prime all that well.
There's a reason the idle speed is 740 RPMs vs. something lower. And there is a reason the DME takes the cold engine up to over 1K on a cold start.
(When I start my 996 Turbo the oil pressure gage needle doesn't even hardly come off the bottom of the gage while the engine cranks. It does zoom up when the engine fires and as the RPMs climb.)
As you slow crank the engine in the meantime residual oil is being forced out of the bearings so when you do fire the engine and the RPMs climb there may not be sufficient residual oil present to form the hydrodynamic bearing (oil film) that keeps the bearing surfaces from making metal to metal contact.
The clattering noise is harmless. The engine is better off just firing the engine up normally. This gets the oil flowing the quickest.
There's a reason the idle speed is 740 RPMs vs. something lower. And there is a reason the DME takes the cold engine up to over 1K on a cold start.
(When I start my 996 Turbo the oil pressure gage needle doesn't even hardly come off the bottom of the gage while the engine cranks. It does zoom up when the engine fires and as the RPMs climb.)
As you slow crank the engine in the meantime residual oil is being forced out of the bearings so when you do fire the engine and the RPMs climb there may not be sufficient residual oil present to form the hydrodynamic bearing (oil film) that keeps the bearing surfaces from making metal to metal contact.
The clattering noise is harmless. The engine is better off just firing the engine up normally. This gets the oil flowing the quickest.
Which reminds me that when rebuilding an LSx engine, they have a port on the side of the engine block that taps into the main oil passage after the oil pump. Its meant to be used when an engine is freshly rebuilt to pump oil manually with air assist prior to starting the engine up. Yes the LSx is a totally different platform, and yes a freshly rebuilt engine is alot dryer than an engine that had an oil change but the concept remains the same. I wonder what the protocol is for a freshly rebuilt M96/M97.
Anyways I went on a tangent there, point is I think trying to avoid the clatter at startup after an oil change is a good idea. Really no downside other than the extra step of pulling the fuse.