Car Got Stuck On 9000 Revs Without Me Doing It

[RB20_ZED]

To cut a long story short. Was driving today and the car seemed to accelerate without me making it. I pushed the clutch and pulled it into neutral and the engine reved quickly up to 9000 by itself and stayed there until i was able to cut the power to the fuel pump (luckily i have a kill switch). Im guessing that the accelerator cable got stuck but it seems fine and im worried that it could be caused by something else - maybe turbo/boosting related? I wasn't driving the car hard at all when it happened.

what would cause the engine to spike to 9000 revs and stay there? besides the accelerator cable/pedal getting caught or stuck.

my car seems fine now but im scared to drive it without knowing what may have caused it since the cable doesnt seem like it had anything to get caught on.

any help/opinions would be appreciated.

[Al]

The only thing that could cause the engine to rev is jammed accelerator cable or jammed throttle body.

Make sure the cable is not frayed, or does not have resistive tendancies as you let go of the peddle (maybe frayed within the insulation conduate). Best to have a mate inside the car pressing acc on/off and you looking in engine bay. Make sure that nothing is obstructing or can obstruct the cable and throttle body. Remove the inlet pipe and cable from the throttle body, insure the shutter moves freely and smoothly. Ensure that all screws, fittings, etc are tight. Check that the return spring is operating correctly and in a fast manner.

May help to post pics of your throttle body and cable, from various angles (top, sides, front, back, etc.)

[RB20_ZED]

thanks for the help.

[cowie165]

Great post Al.

Last year I bought a Mazda 626 quite cheaply because the owner (rich guy in Mosman) was worried about an 'engine surge' that caused the motor to rev out to redline with >3/4 throttle. With the bonnet open, it was immediately apparent that a rubber hose was interfering with the throttle cable and holding it open for a few second until friction let the cable slide off the rubber...

He didn't care - he'd already bought a new Volvo 4WD to replace it!

[ULOOOK]

Also check the throttle spring is intact and working, a faulty throttle spring will cause it to stay wide open.

[MANWHOR3]

by cutting the fuel pump at 9000rpm, you may have leaned your motor out.

I would never do that.

[cowie165]

What would be better? Unplug the ignitor? Cut the spark instead of the fuel...?

[Al]

What would be better? Unplug the ignitor? Cut the spark instead of the fuel...?

Just turn the ignition key to "off" .

[cowie165]

Hrmm, I'm confused.

Is it unplug injectors/fuel pump and lean the motor out;

or unplug the ignitor/plugs and risk hydraulic lock?

[Al]

Good point....

Time to ask an expert

I still say, turn the key to off

[ylwgtr2]

i say also check your bac valve.....i have had some cars that do a similar thing but not to the extent of 9000rpms....also to kill the engine i say pull out an efi relay or yank off the crank angle sensor wire.....i cant see hydraulic lock from pulling out spark as unburnt fuel will just be forced out the exhaust valve on exhaust stroke....

[Al]

Thanks for that Troy.

I have edited my previous post, not to confuss anyone

Just expand on the hydrolic lock question.

If unburnt fuel (no spark) is able to escape through the exhaust valve, why not water?