What would cause this?

Gooberlx2

Lifer
May 4, 2001
15,381
6
91
Twice now (over probably two months) my wife's '08 Honda Civic EX coupe, 5-speed manual, has revved to redline while sitting at idle (clutch disengaged). She had to turn off the engine twice to get it to stop.

Everything is under warranty, so it's no problem getting fixed, but what would cause this?
 

Kabob

Lifer
Sep 5, 2004
15,248
0
76
I know there's an idle speed setting knob somewhere, that mighta somehow been changed...but if it's only happening every once in a while I have no clue why.
 

MDE

Lifer
Jul 17, 2003
13,199
1
81
My best idea would be an electrical problem since the Civic is drive-by-wire.
 

Demo24

Diamond Member
Aug 5, 2004
8,356
9
81
Will it go away if you engage the clutch? If so, and if its getting cold now, then whats likely wrong is that it's doing it's 'warm up' setting, but it's not set correctly causing it to rev too high. Generally it will only raise the revs to about 1500 or so.
 

Gooberlx2

Lifer
May 4, 2001
15,381
6
91
Originally posted by: DEMO24
Will it go away if you engage the clutch? If so, and if its getting cold now, then whats likely wrong is that it's doing it's 'warm up' setting, but it's not set correctly causing it to rev too high. Generally it will only raise the revs to about 1500 or so.

I dunno...it hasn't happened when I've driven the car. I think she's afraid that she'll either destroy the tranmission if she tries to engage it at redline, or that it'll engage and she'll smack the shit outta the person in front of her.

We'll just have to get an appointment made at the dealer...there's some other warranty fit & finish work that needs to be fixed anyway.
 

thomsbrain

Lifer
Dec 4, 2001
18,148
1
0
I'm pretty sure that car is drive-by-wire. There may be a dying throttle position sensor or something.
 

SpeedEng66

Diamond Member
Jul 10, 2002
4,501
1
81
bad tps will throw a cel and put the car in limp mode
the same goes with a bad pedal sensor

double check if the floor carpet is in the way/ slides into the pedal
 

Demo24

Diamond Member
Aug 5, 2004
8,356
9
81
Originally posted by: Gooberlx2
Originally posted by: DEMO24
Will it go away if you engage the clutch? If so, and if its getting cold now, then whats likely wrong is that it's doing it's 'warm up' setting, but it's not set correctly causing it to rev too high. Generally it will only raise the revs to about 1500 or so.

I dunno...it hasn't happened when I've driven the car. I think she's afraid that she'll either destroy the tranmission if she tries to engage it at redline, or that it'll engage and she'll smack the shit outta the person in front of her.

We'll just have to get an appointment made at the dealer...there's some other warranty fit & finish work that needs to be fixed anyway.



Uh, no thats not what I meant. I meant push in the clutch, not releasing it.
 

Howard

Lifer
Oct 14, 1999
47,982
11
81
Originally posted by: DEMO24
Originally posted by: Gooberlx2
Originally posted by: DEMO24
Will it go away if you engage the clutch? If so, and if its getting cold now, then whats likely wrong is that it's doing it's 'warm up' setting, but it's not set correctly causing it to rev too high. Generally it will only raise the revs to about 1500 or so.

I dunno...it hasn't happened when I've driven the car. I think she's afraid that she'll either destroy the tranmission if she tries to engage it at redline, or that it'll engage and she'll smack the shit outta the person in front of her.

We'll just have to get an appointment made at the dealer...there's some other warranty fit & finish work that needs to be fixed anyway.



Uh, no thats not what I meant. I meant push in the clutch, not releasing it.
That would be "disengage", then.
 

AMCRambler

Diamond Member
Jan 23, 2001
7,715
31
91
Could be throttle body getting stuck open. Had that happen on my Ford. It would also stick closed. It wasn't drive by wire though, so I could feel the stiffness in the pedal the first time I depressed it after it had been parked a while, you'd push hard and it would pop loose and then be fine. Took the intake and throttle body apart and the inside of the throttle body was pretty gummed up with sticky black stuff. Cleaned all the snot out of it and the problem went away. It was pretty easy to see it just by taking the intake tubing off and then actuating the throttle so that the butterfly was open and I could look in there. I'm sure that same black crud was all over my intake manifold too but I wasn't about to rebuild the whole thing.