Fuel mixture, CO% level

[jaydev]

Hi,

I was wondering if anyone knows how to adjust the mixture on a 5.3 HE with Marelli Ign?

My car is running fine and pulls niceley, but when i get out of the car and go to the back of it, there seems to be an over rich mixure. Also the idle fluctuates when warmed up, All Ignition and services are up to date.
I do posess a gas tester to carry out the check.

Thanking you in advance.

Jay

[dommichell]

I had a similar problem on my v12 XJS. It was caused by the aux air valve (rear of the left hand bank) not operating correctly. This is a wax filled item which allows extra air into the system when cold and should shut off this flow once the engine has reached running temperature. Over time these can fail which then leads to poor idle and poor mixture as the electronics try to compensate. Hope that this is of some help to you.

Dom.

[jaydev]

Thanks Dom,

I will see if i can fault find. When you say the left hand bank would this be viewed from the front or rear of the car?

Thanks

Jay

[dommichell]

From the drivers seat. The AAV looks like an aluminium tube, about 4 inches long with a feed from the air intake and then around to the inlet manifolds. It is reasonably easy to remove from the engine but be careful if it is hot as removing the AAV leaves an open hole into the coolant flow. If you put the bulb at the bottom of the AAV into boiling water you should see it close off the side port. If not then try cleaning it with some carb cleaner before going any further and test again.

Dom

[jaydev]

Many thanks,

I will let you know how i get on.

Cheers

J