Aux Air Valve

[Jammer]

Just removed and replaced the aux air valve on the 280SE. (again)

This is the second unit I have tried. On cold start the idle sits at 600RPM and after a few minutes the temperature AND the idle increases to the 1150 RPM that you would expect. Then after the car is well and truely warmed up (80+) the idle returns to a smooth 600RPM (In Drive with Air con on). 700 RPM in park.

I suppose I should just leave the bloody thing alone now and be thankful its smooth and problem free. (YES - I hear you all say at once!!!!)

Anyway, would love to hear any comments about the cold start 600RPM. Cold start injector is working OK. And the car has NEW Bosch plugs, leads, distro, rotor, coil and ALL vac lines have been replaced with new "ducks nuts" silicon all in pretty colours.

John

 

[Styria]

Hi Jammer, you basically pre-emptied of what I am going to say - don't take too much notice. However, what made you replace the valve in the first place, and this time ? Did you buy new, or fit second hand.

One other item to check is the warm-up regulator - its pressures should be checkedwhen dead cold and also once the engine is fully warmed-up.

The vacuum lines - any information as to where you bought them ? You say they are all the pretty and, I presume, correct colours. Regards Styria

 

[WGB]

I have heard that sometimes in warm climates a restrictor is put into the air line to the valve to prevent the engine from revving too much at a cold start.

My 6.9 runs at about 1200 revs after first startup but my 450 will rev up to about 2,000 rpm for a few seconds before slowly settling back down. Neither engines need these sort of revs to run happily when cold.

If the system worked perfectly with the sort of control you have with a modern engine there would probably be no detectable difference between cold and hot idling but these older systems are not that perfect and were designed to handle a wide extreme of temperatures with a lot of reserve for very cold starts.

?Do you have a restrictor in the line to the valve.

Yes - I agree with you - unless you have cold starting problems I would leave well alone and fix something else that needs your attention.

Bill