SL/R230: Engine revs to redline on start
Thread Starter
Junior Member
Joined: Jan 2013
Posts: 58
Likes: 6
From: Memphis, TN Metro
2017 SL550
Engine revs to redline on start
I’m concerned because my 2009 sl550 starter revs the engine all the way to the redline, although for only about 1 second. This happens whether I use the key or the keyless go button. No foot on gas pedal at all.
I have just become aware of this, so I don’t know if it has always done this or not.
So is this normal, or do I have a serious issue I need to get checked out?
thx much.
Reid C
I have just become aware of this, so I don’t know if it has always done this or not.
So is this normal, or do I have a serious issue I need to get checked out?
thx much.
Reid C
Member
Joined: Feb 2018
Posts: 160
Likes: 32
2005 SL55 Completely Built Motor
No it's not suppose to redline when you start it. It's isn't good for engine at all.
I'm concerned that you don't know if has always done that. I find that odd as I think anyone including your neighbors would know if your big V8 rev to redline on each start up. So are you sure the engine itself is going to redline and not just the gauge?
I'm concerned that you don't know if has always done that. I find that odd as I think anyone including your neighbors would know if your big V8 rev to redline on each start up. So are you sure the engine itself is going to redline and not just the gauge?
Thread Starter
Junior Member
Joined: Jan 2013
Posts: 58
Likes: 6
From: Memphis, TN Metro
2017 SL550
Thanks for the reply. Here's what happens: I start, the engine seems to rev a bit. It definitely does not seem like it revs all the way to 7000 rpm, now that you asked, and I went out and started it and listened. It seems to rev MAYBE a slight bit over what I'd like, but it may in fact be normal. The gauge jumps up to the redline area, around 7000, but only for a second and then settles immediately back to a normal cold-start level (or warm start, if its been running).
So, it seems like its a gauge thing much more than engine.
Thx,
R
So, it seems like its a gauge thing much more than engine.
Thx,
R
Member
Joined: Feb 2018
Posts: 160
Likes: 32
2005 SL55 Completely Built Motor
Not sure what would cause the gauge to spike like that. This is one of those issues that if it isn't effecting anything I might just leave alone or wait until the next time your in the shop for something and just ask few question about it and see its worth figuring out.
A disconnected/leaking vac line will usually cause very erratic RPM's. But it won't be running very well either and high chance of check engine light on. So leads me to think more electrical glitch than anything.
A disconnected/leaking vac line will usually cause very erratic RPM's. But it won't be running very well either and high chance of check engine light on. So leads me to think more electrical glitch than anything.
