General Question

Fred931's avatar

Automotive oddity when starting up?

Asked by Fred931 (9392 points ) April 19th, 2010

My dad’s ‘04 Toyota Sienna likes to be different whilst starting up. After I stop using the starter, there is a period of about a ½ second to 1 second of silence, though the rev counter climbs to something that varies under 1000 RPMs. After this short period, the engine will either stay very quiet, but become actually audible and stay near 1000 RPMs, or it can surge up to 2500 or even 3000 RPMs. Is this just me not getting used to driving, considering I just started getting behind the wheel, or is this an actual mechanical problem? If it isn’t just me being a noob, is there anything I can do to make it stop, though this is probably harmless?

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15 Answers

dpworkin's avatar

Maybe your idle is set a little low, or your mixture is a tiny bit off.

Axemusica's avatar

Surging is always a problem, but is this during cold weather? When’s the last time said vehicle had a tune up?

Axemusica's avatar

@dpworkin don’t confuse him with mixture lol, he just got behind the wheel.

njnyjobs's avatar

it may also depend on the engine temperature, the ambiant temperature and humidity.

WestRiverrat's avatar

Are you using ethanol or straight gasoline?

Fred931's avatar

@dpworkin Explain how to adjust these (or how a mechanic would).

@Axemusica High today was around 80. That would be pretty chilly if you lived in, say, hell. And I’ve spent some time tinkering and changing oil, don’t you worry, but I still don’t know a lot of things.

@njnyjobs Ambient and engine temps are mild, but humidity is always snarly in south Alabama.

@WestRiverrat Plain ol’ gas-o-leen.

Axemusica's avatar

Actually, here look at this and this I’d start by asking a dealer if your particular model has had that recall first.

Fred931's avatar

@Axemusica All of these recalls don’t seem to relate to the problem I’m having. I wouldn’t have even stepped on the accelerator pedal prior to and while starting the car. I only remember the seat belt issue being a problem. It was annoying as shit, but my dad wouldn’t even take it to the dealer for a year after that recall. The motor on the side door is burnt out as well, but he’s too cheap to cough up $200 for our convenience.

Axemusica's avatar

@Fred931 just because you’re not stepping on the accelerator doesn’t mean there isn’t a problem with it. Make sure that particular recall has been done.

Mixture is air/fuel ratio and can be effect by anything that provides either into the combustion chamber.

Fred931's avatar

@Axemusica It says in the recall that Pop would’ve been notified by this time a year ago. He hasn’t heard or seen anything from Toyota concerning the sticky pedal, so our vehicle shouldn’t be one of the problem kids.

filmfann's avatar

removed by me

Fred931's avatar

Removed by me properly considering I remembered to use italics

ApolloX64's avatar

The slight surge that is randomly up or down sounds like a mass air flow issue. Probably not “off” enough to cause a concern, just hit the pedal and it should come back down. It’s probably just compensating for what it thinks is “thick” or “thin” air depending on the reading. It could be something as simple as moisture sitting near or in the air box where the filter sits and is causing the mass air flow to have a wrong reading on the quality of air. If it’s not showing an engine light and it seems to drive fine and the problem disappears, I wouldn’t worry about it.
Oh, and @dpworkin modern vehicles like an ‘04 Toyota Sienna are all computer controlled when it comes to mixtures, you cannot change them unless you do a re-program. The only way that mixtures can be fiddled with other than that is by bad sensors that aren’t “bad enough” to throw a code. (Coolant Temp, O2, Mass Air, MAP, Fuel Pressure Regulator, Cam and Crank sensors.)

Hypocrisy_Central's avatar

We talking carb or fuel injected?

Fred931's avatar

@Hypocrisy_Central I wouldn’t know of any 2004 vehicles that would still use a carburetor. The latter.

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