[xj] Re: Mixture/AFM and the Fluke 98

In a message dated 02/14/2000 8:44:03 AM Eastern Standard Time, JaguarBud

<< I can’t get my idle lower than 925RPM. When I got the car, it was up
around 1050. I turned the hex in the air distribution block all the way in,
which resulted in 925. I’ll check that the butterfly is at .002.
This is the most important thing to check but clean that whole area with
ThrottleBody Cleaner First…
If that’s OK, would you recommend changing the idle adjustment atop the AFM,
which you mentioned before?
Bud this will not change idle speed…only the idle mixture.
Would changing it alter my O2 readings?
Yes it would, but only at idle. BTW, this is the screw I keep messing with
to try and smooth out my idle = nothing is working for the better…
How does one find air leaks?
This is a slow and laborius process. I purchased a hand operated vacuum pump
from Pep Boys and went over the entire car but first I replaced all the
hoses. Plus, make sure that the curved rubber hose between the AFM and the
throttlebody is fitting tightly. Last thing to check is the ignition amp
which is mounted at the front of the intake manifold. The course threaded
screws that hold it are a known source of vacuum leaks…wrap them with
teflon tape and screw them back in place. And finally there is a small unused
pipe at the rear bottom of the intake manifold that is supposed to have a
rubber cap over it to seal it. It falls off/cracks with age. 'Must be

Oh and did you know Fluke makes an attachment for our 98’s that will allow it
to scope ‘vacuum’ as a means of diagnosing engine problems? Maybe I will look
on Ebay and see if there is one out there for cheap.


Ted Macklin
Atlanta, GA