Engine reving up by itself.

Woody_FX · 27-08-2008 9:25am #1

I've noticed over the last 2 weeks as i drove down the canal at 5mph on my way to work that the car would jump forward at times. Like i stood on the accelerator for a second. I can see the rev counter jump a little. I've also noticed the temperature gage flicks around. Anybody have an idea whats going on? I dont think its the temperature since i am only traveling short distances, buy maybe an electrics problem? Or maybe those 2 things are completely unrelated.

Its a 2002 Disesl Avensis btw.

Anybody able to shed some light on what the problem maybe?

Thanks
-Woody

emagination · 27-08-2008 9:51am

Could it be air-conditioning kicking in? Does it happen with air-con switched off?

voxpop · 27-08-2008 10:00am

Sound like you have a faulty temperature sender anyway

mike65 · 27-08-2008 10:06am

Could have an airbox contaminated with deisel/oil residue I think that can cause revving as the mix is enriched.

Mike

maceocc2 · 27-08-2008 10:30am

mike65 wrote: »

Could have an airbox contaminated with deisel/oil residue I think that can cause revving as the mix is enriched.

Mike

I would say the same alright, or faulty air intake valve could be the problem, meaning air to diesel mix is wrong

DublinDilbert · 27-08-2008 11:29am

voxpop wrote: »

Sound like you have a faulty temperature sender anyway

I would assume extra fuel would be injected if it thinks the engine is cold also, so that might account for the fluctuation in revs.

Typically they use an NTC thermistor who's resistance will increase as the temperature drops, hence an open circuit will be read as a cold value... If the sensor is going "fully open circuit", this should be logged by the engine ECU as a fault. It could be intermittently going open circuit, hence the ECU may well think its ok...

antodeco · 27-08-2008 12:15pm

mike65 wrote: »

Could have an airbox contaminated with deisel/oil residue I think that can cause revving as the mix is enriched.

Mike

+1 Defo sounds like an air intake issue.

Woody_FX · 27-08-2008 5:30pm

Hmm can i clean that myself without having any tools or would it be a job for my local mechanic?

Problem seems to be more pronounced lately (or could be just that i am noticing it more).

dainius · 28-08-2008 6:28pm

have you checked the coolant level? Does your heater work properly? Last time it happen to me I blew the head gasket.

JimmyCrackCorn! · 28-08-2008 6:51pm

cheak for any leaking breather pipes aswell

gobby · 28-08-2008 6:52pm

Ouch, you dont wanna blow the HG. Mechanic time methinks

Engine reving up by itself.

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