Engine redlined on its own

NachaLuva

NachaLuva

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Cruising up to a red light tonight, had the gears in neutral, foot off brake & off accelerator, when the engine suddenly redlined on its own! :eek:

I quickly put my foot on the brake which instantly dropped the revs. This make me think something funny happened with the cruise control...thinking it needed to accelerate until the brake activation provided the cut out.

Has anyone else had this problem? Possible reasons other than cruise control gone glitchy?
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I should mention this is the first time my baby has seen the redline...I dont know who was more surprised, me or her! :(
 
No idea of what it comes from, is it an OEM cruise control ?
 
Check the throttle cables from both accelerator and cruise controls where they connect to the throttle body. I had the nuts come loose on my WRX once when on WOT- and it stuck there. Things got very interesting as I I had to react very quickly from ramming another car before switching off the engine. All this took place in about 2 seconds, but what a ride. No work had been carried out on the car- it just happened.
 
Yep! Happened to me out of the blue in stopped traffic, hit about 7K in about 1 second. Flicked the custom isolator switch about 1/4 second later to kill it.

Restarted and all OK except for the puffs of white smoke out the back pipe.

Scared the B'Jesus out of me and it was not a nice sound either!

harkari?
 
Cruise control hadn't been on, I'd been driving with my right foot then slipped it into neutral when the light went red & was coasting when after about 10 sec it redlined out of the blue!

I had slipped it out of gear without the clutch (lazy lol, just revmatched), but the CC hadnt been on so that shouldnt matter.

PigSti said:
Scared the B'Jesus out of me and it was not a nice sound either!
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Mine sat on exactly 6500 until I hit the brake cutout, didnt sound bad though

harkari?
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Lol :raspberry:

jf1sf5 said:
No idea of what it comes from, is it an OEM cruise control ?
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Yep standard OEM

Rally said:
Check the throttle cables from both accelerator and cruise controls where they connect to the throttle body. I had the nuts come loose on my WRX once when on WOT- and it stuck there
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OK I'll do that, thanks
 
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Mine red lines at about 6200/6300. Sounds fine, too :lol: :rotfl: :lildevil: :cool:.

It get there at least once a week in first and/or second ... :raz:.

Keeps the "carbon moths" from laying "eggs" in the cylinder heads, piston crowns, around the upper piston rings, inlet and exhaust systems and around the valve heads and stems :ebiggrin:.

But that must have been scary for a moment or two ... :(
 
Ratbag said:
But that must have been scary for a moment or two ...
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Yep, it just happened while idling, go figure!

I tend to baby engines and I'm not a revver either (silly old happy bugger :biggrin:) so 5K is my red line.

The ziiiiiiiiiiiinging sound of hi revs has from experience preceded the "clang thump bang-a-clang-a-bang grrrrrrrrr rrrr" sound before the painful human gimme-gimme "$$$$$" sound :twisted: appears, so I try not to go there very often.

It's called Boxer BLAH?
 
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Gidday Pigs

I'm also a member of SOFA (Silly Old Farts' Association ... :iconwink: :lol:).

However, I don't think I ever managed to completely get rid of the "screaming wheelie, milk bar hoon boy" part, even at my advancing age :rotfl: :lildevil:.

Drove Roo1 like I stole it a fair bit, but am somewhat gentler with Roo2. But giving an engine a good rev about once a week is needed to keep the engine clean and happy - according to Jaguar's 3.8L E-Type manual, to keep the engine clean and de-carbonised " ... the engine must be taken to at least 5,500 rpm in second at least once a week." That's around 96 mph ... ;) :biggrin:. Been there, done that ... :lildevil:
 
PigSti said:
I tend to baby engines and I'm not a revver either (silly old happy bugger :biggrin:) so 5K is my red line.
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Same here. I'm happy going to 4000 a bit & rarely to 5000 but I dont think valves, rings, bearings, etc really like much above that
 
The WRX makes maximum power for 3000RPM till around 7000RPM. It likes it up there- who am I to hold it back....
 
Rally said:
The WRX makes maximum power for 3000RPM till around 7000RPM. It likes it up there- who am I to hold it back....
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How often do you take it above 5-6000? How's the reliability affected by doing this on a standard engine? Also, I know there are 3 types of EJ25 blocks, open, semi-closed & closed deck, AFAIK there's only an open deck EJ20...I wonder how the reliability of an ageing EJ20J is affected by routinely high revving?

Also, do EJ's have valve springs? I know on other engines they dont like hard revving & after a while they break...
 
Every time I drive it at least once for the thrill, because it feels so good. But then I just cruise around . Take yesterday. I gave it one blast getting on to the motorway, and then just cruise while others overtake me. On the skidpan- it is regularly on the redline. In normal traffic the car has more than enough power not to need redlining to get ahead.

All road cars except rotaries run valve springs. F1 and MotoGP run pneumatic valves. The revs will affect valve springs, especially if you over rev the engine. But revs alone won't affect the block except wear will occur over a shorter period of time. What will affect it is boost and tune. In the end, you get nothing for nothing but I bought this car for the thrills, knowing it will need re-building earlier than say the Forrie will. But it will be worth it.

NachaLuva said:
How often do you take it above 5-6000? How's the reliability affected by doing this on a standard engine? Also, I know there are 3 types of EJ25 blocks, open, semi-closed & closed deck, AFAIK there's only an open deck EJ20...I wonder how the reliability of an ageing EJ20J is affected by routinely high revving?

Also, do EJ's have valve springs? I know on other engines they dont like hard revving & after a while they break...
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Mine only does that if i forget the cruise is on an try to change gears, the cruise control throws it up to redline, then the ecu cuts the throttle, then the cruise control lets go.
 
idw said:
Mine only does that if i forget the cruise is on an try to change gears, the cruise control throws it up to redline, then the ecu cuts the throttle, then the cruise control lets go.
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Mine does that too but only if trying to hold speed on a steep hill, ie, the CC is pulling hard on the throttle & it takes a moment to let go. But it only revs up to maybe 4500.

This was a glitch in something. I've checked the nuts at the throttle body & the CC unit, all tight. But the CC was even on! The other possibility is the IAC valve but I dont really know what I'm doing there lol.

Maybe it was a once off...I hope so...
 
Gidday NL, Id etc

I think that Subaru must have changed the way CC works in the SG - by the time mine was made, anyway. Either that, or mine is adjusted absolutely perfectly.

The very moment I touch either clutch or brake pedal, CC turns off.

It's rather nice in SWMBO's SH (auto) when one has CC on, one can just start accelerating from lights etc, then hit the RESUME button at about 10 km/h. It then smoothly accelerates back up to the set speed. Except that I don't really like automatic cars ... :poke: :iconwink: :cool:.
 
I have had this happen once, on purpose. Happened when I slipped the car out of gear when the cruise control going to see what would happen. Strange though because if any of the cancel switches where faulty (break and clutch pedal) your cruise control wouldn't work at all, unless they where both shorted out. May have been for one too many swims :P
 
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