one part solution or multiproblem nightmare??

[White2505 0]

Vehicle 1.8 16V

symptoms:-

 

when cold engine starts perfectly fine, revs rise to just over 1K then almost immediately drop off to around 650 (almost stalling) then rises to about 1k and sits steadyish.

 

when pulling away there is little power low down the rev range and the engine runs a little rough.

Once pulled away and start to up the revs the engine smooths out some and she pulls like a train higher up the rev range 3500rpm +

Once warm these symptoms lessen and the drive is smoother although there is a sense of jerkiness when sat at a fixed speed with fixed revs on the road.

 

final possible red herring... mpg on mfa1.. the lcd display on start up sits at 99.9 mpg and stays there for about 4-5 miles then starts dropping a few miles per hour at a time until it sits around the 12mpg mark.

 

I know this can't be right or I'd have run out of fuel twice now!

 

so as the title says is there a one part 'cureall' or do I have a mix of problems??

[Kevin Bacon 5]

Sounds like you need to administer a 16V medical checkup....

 

First of all, make sure the idle valve switch is working OK. It's the little microswitch on the the throttle body. Then clean out the idle valve as they often stick.

 

Then you need to set the base CO to 2%. Engine needs to be hot.

 

To do that, disconnect the red lead under the ignition coil.

Remove the breather hose from the airbox and plug the airbox hole (a walking stick rubber end works well there).

Arm yourself with a long 3mm allen key.

Start engine.

It will be lumpy and idle low.

Turn the brass screw on the throttle anti-clockwise until the revs level off and hold at 1000rpm.

Now poke that 3mm allen key into the tiny hole in front of the metering head air boot.

Without pressing down, turn the allen key clockwise slowly until the revs smooth off (or anti-clock if clockwise makes it lumpier)

When the idle is dead smooth and steady.

Switch off and reconnect everything and you're done. It should then run a lot better.

 

Make sure also that the blue 5th injector is working OK. You can remove it and start the engine with the injector in a jar when cold and make sure fuel comes out for a few seconds.

[White2505 0]

Nice one, thanks for that, now know what I'm doing on my days off!!