Re: Open Loop??

[Huw Powell <audi@mediaone.net>]

Jeff Goldberg wrote:
> 
> Hey Guys,
> 
> I have been trying to "tune" my 86 4KCSQ by ear and have made good progress.
> It runs really smoothly when warm, but a little rough when cold. Starts a
> bit hard too. My only criticism of warm idle is that it will sit at anywhere
> between 800 and 1100 RPM when stopped for instance at a light. This choice
> seems random. No surges, just inconsistent idle speed.
> Got a dwell meter to check duty cycle at the test connector. There is
> absolutely no dwell change when mixture or duty cycle settings are changed.
> Am I running in open loop?

the duty cycle you are testing on a CIS-E car is the ISV duty cycle. 
While it may change slightly is is not really directly related to
mixture.  To check the static mixture setting you measure the current to
the control pressure actuator on the front of the fuel dist.

pix at my web site of these things being tested/adjusted under the
timing CIS-E heading.

> I know the PO put in a new Ox sensor and possibly disconnected in a way that
> the computer goes into open loop. I have deduced that from posts on the
> list. If so, how to reset computer??

you don't have to "reset" it.  open loop would be due to either temp
sender saying it is still cold or no useful OXS signal (pretty sure of
this but not 100% certain).

> My mechanic has some spare computers. If the computer is the problem, does
> anyone know the part # for my computer?
> 
> BTW, I tested the Ox sensor according to Bentley. Heater has proper
> resistance and it is getting 12v (actually 13) at the connector.

but what is the output voltage doing?

-- 
Huw Powell

http://www.humanspeakers.com/audi/

82 Audi Coupe; 84 4kq; 85 Coupe GT; 73 F250