Re: 88 MB Urq questions

["Lawson, Dave" <dlawson@ball.com>]

Lino,
>
I have been following this thread with interest, and I would like to put
some questions up for grabs regarding my Ur-Q.
The previous owner appears to have replaced the engine with a MC, and
definitely installed a MAC11b on my 83 Ur-Q.
My car has a problem similar to the one reported by Phil on John's car.  In
my case it accelerates rapidly until it gets to about 4500-5000 RPM and then
sits there surging taking forever to get to 6000 RPM.
The MAC11 seems to be controlling some functions like timing, but how can it
control the fuel management if there is no duty cycle frequency valve.
I'm thinking of installing one and observe the results any thoughts.
There is a solenoid valve controlling vacuum at the warm-up valve,  I can't
get any info on this system on Bentley's nor Haynes.  It turns vacuum on at
the warm-up valve when the ignition is on, but that all I know.  Does
anybody have more info on its function?  Any information would be
appreciated.
>

So you have verified that you have a MAC11b ECU installed in your 
urq. And you have running problems in the higher rpm's.
A few comments:
- The MC uses an O2 freq valve so it does control fuel. It is mounted
on the side of the fuel distributor.
- Make sure you are using the MC specified Air temp sensor, the urq
sensor does not work withe the MC MAC11 ECU. BTDT.
- Make sure all the other MC engine based sensors are hooked up and
working correctly, including coolant temp sensors and switches.
- Make sure the idle and WOT switches are working. I am using a set
of early 5kT separate switches on my car with the MAC11 and this works.
- I am using the complete ur-q fuel system combined with the MC wiring
and have had no problems for 3 years. It just plugs into the urq O2 freq
valve connector. I am using the MC engine control pressure regulator
mounted on the side of the engine.


I don't understand what you mean by "solenoid valve controlling vacuum 
at the warm-up valve", so I can't comment.

HTH
-
Dave Lawson  Boulder, CO
90 200 TQW, the tranny is out again today
83 urq with MC engine running fine