[urq] RE : URQ quirqiness

[Buchholz, Steven]

... it would be interesting to see what the OXS voltage is at the time this is happening.  Basically what it sounds like is that the OXS control is getting an indication that it wants to lean out the mixture ... and even at full rail it is not lean enough.  Are you *sure* it is going to -0- and not 100%?  I don't think I've ever seen anything below something like 4% myself.  Do you see the duty cycle walk its way down to zero or does it jump from something more reasonable?  Have you tried whacking the throttle WFO when the condition arises to see if the duty cycle goes to the correct value?  

It may very well be the case that the OXS control system is working fine, and something's going wrong inside the engine that is causing the problem ... i.e. the OXS FV shutting off is a symptom, not a cause.  I saw someone mention balky fuel injectors ... could be fuel or control pressure fluctuations ... intermittent spark issues ... etc.  

Steve B
San José, CA (USA)
> 
> When it acts up the FV goes dead quiet, and the duty cycle goes to 0. No
> variation, just nothing. It isn't trying to compensate or the like- it just
> comes on line and goes off. When it is online it fluctuates and controls
> normally.