Tickover

[coffeecup]

Hi
Anyone know how I can increase the tickover on my 1.4 i-shift, it's about 500rpm, and dosen't like it.

mike

[applicationcen]

Increasing the revs will very likely engage the gears via the clutch attempting forward or back movement even with your foot on the brake.


At best your clutch will wear badly - at worst you smash through the conservatory doors and end up in your luxury swimming pool!

There are three things that disengage gears at idle - Foot brake, handbrake or placing it in neutral.

Increasing the idle rev speed when in a forward or reverse gear WILL alter the clutch and WILL engage gear.

If the revs are below the factory settings - go to a qualified dealer. Get someone who actually knows what they are doing to fix it.

 

[coffeecup]

If that is so, why does it not engage gear when the car is cold and ticking over at about 1000rpm ?

Mike

[guest5079]

Given the cleverness of modern computers, is it not probable that when cold and the tickover is increased that compensation is made by the software using input from the radiator temperature sensor.
If VW can do what they have done I should  have thought this sort of simple electronics were possible.
Remembering back to my Rover V6 auto, when cold there was a slight nudge when engaging drive, although it would creep it didn't rush forwards, so given progress in the motor industry, I guess anything is possible.
Any software designers out there?

[applicationcen]

Auntyneddy is correct in that assumption.

An  ECU  takes account of engine oil pressure, engine temperature, vehicle speed, engine speed and throttle position, plus hand brake. AND controls the release of breaks on hill start and actively enables or diseables bunch of other functions.

Any cold engine requires an amount of priming - that is the air + fuel has to be made to combust at a lower temperature. At a normal operating temperature the ECU ensures the car drinks a lot less at a lower speed by almost starving the car - lets call it economy mode.

Unless the ECU steps in to compensate you would never get it started or running. Hence the cold start profile keeps those revs higher with the valves sucking more juice and air. After it is warm enough it will revert to economy mode.

This then causes a problem when you want to get up to high speeds because economy mode is not up to the job. It is actually the cam shaft profile that physically controls the air + fuel mix. At high speed the ECU forces a bolt locking the second cam profile in play - that's where all the amazing top end performance comes from in Honda's Vtec.