Revving high

[vernremy]

I have a 2004 Matrix with 60000k and it starting to rev high on cool mornings. Is there any cause for concern here? I was considering a spark plug replacement, but it is kind of early.

Any suggestions?

[matrixdude06]

seems normal to me, mine does that sometimes, all cars do

[l-man08]

This is normal. This has to do with cold start emissions. I am no genius, but the computer tells the engine to rev up, send heat through the exhaust, and into the catalytic converters. Sensors on your motor know that the car is cold, and needs to warmed up. This is where the cold start valve comes in handy.

A cold start valve(is like another injector) is their to put fuel into the intake manifold as the motor turns over. It then creates a air/fuel mixture so it can start better.


As from what I heard is that you can put the car in neutral and rev the motor to about 3000-rpm, no more on cold starts. Never red-line the motor while cold engine starting.





Read this it might help....

http://www.nrel.gov/vehiclesandfuels...dfs/techbr.pdf

[Smar969905]

you say high revving...How high of a rev do you get up to?

i drive a 2003 xrs and i have been having cold mornings lately, so my idle speed is set by the computer to be the 'high' idle so i sit about 1800-1900 rpm. my 'mid' idle is about 1000-1200 rpm, and my 'low' idle, for when the car is warmed up entirely is about 700-900 rpm.

[l-man08]

Also the oil in the engine is thicker, which causes the engine to force more heat to get things as normal. If you don't like waiting, change your oil, and get synthetic oil if you don't have it now.