RE: 4KQ OXS & rev limiter ?

["Buchholz, Steven" <Steven.Buchholz@kla-tencor.com>]

> I need to get like 300-500 more RPM before the rev-limiter stops the fun.
> Any easy ways to do this? Is this controlled by the fool-pump relay? Could
> the relay be modified to increase the rev limit?
> 
The rev limit is definitely in the fuel pump relay.  I've heard tell that
some of the FPRs from older cars w/o rev limit are compatible, you might
want to try that.  I know that my '78 Audi Fox does not have a rev limiter
... if I have a chance I'll pull the relay on that and compare it to the one
in the '85 4kSQ.  You could also reverse engineer the timer circuit and
change the RC value to let it go just a bit higher.  

> Another question: I replaced the 3-wire heated oxygen sensor in my 84 4KQ
> RR car and also replaced the faulty HalMeter AF30 mixture meter. The meter
> works OK now but it appears that the system never goes closed-loop. Is
> this
> because the sensor does not get hot enough without the integral heater?
> Does something sense the open-circuit for the heater and disable
> closed-loop mode? I would have thought that the heater was just for faster
> warm-up for emissions purposes and that it would eventually get hot
> enough,
> guess not?
> 
Do you mean that you replaced the 3-wire with a 1-wire?  If your OXS is
mounted in the nose of the cat like it is on my '85 there's no way the OXS
is going to get hot enough to operate correctly, at least during most around
town driving anyway.  The PO of my car had a 1-wire installed, and the car
used to run like crap after it warmed up.  AFAIK the system closes the loop
based on coolant temp, it assumes that the OXS is warmed up by the time the
head has.  

HTH!
Steve Buchholz
San Jose, CA (USA)