[urq] Looking for a MAC-02 for 1983 URQ
a_stickler at yahoo.com
Tue Nov 1 15:56:38 EST 2005
By stuck, I mean that I can't adjust it at idle. It
moves around a bit while the car is warming up, but
then, once warm, it's at 50 and only responds to
tripping the FT switch.
I will check the possibility of the switches being
swapped. I hadn't thought of that. Thank you.
I've gotten a few responses. Hopefully, I can find one
--- "Buchholz, Steven"
<Steven.Buchholz at kla-tencor.com> wrote:
> Where are you located? I have an extra one I can
> dig out if necessary,
> but I'm a bit hesitant to ship it anywhere ...
> Duty cycle stuck at 50% ... have you verified the
> functionality of the
> Idle and WOT switches at the ECU? You say that you
> can see the ECU
> responding to the Idle/WOT switches ... are you sure
> you don't have them
> I guess I'm a bit confused by your post ... at first
> you seem to
> indicate that the duty cycle is stuck at 50% ... but
> then you say that
> with both Idle & WOT switches tripped you are seeing
> 75%. Do you know
> if the switches were replaced at some point? It
> almost sounds like
> you've got a normally closed contact where the ECU
> is expecting a
> normally open one. Here again, check the switch
> status per the IST docs
> at the connector the ECU plugs into ...
> Page 21 of Maint & Adjust shows the idle switch is
> on pin 15 to the ECU,
> and the switch should read 0 ohms to ground when the
> throttle is at the
> rest position. When the throttle is off idle the
> resistance should be
> infinite. Full Throttle switch is on Pin 21 and
> should be infinite ohms
> normally, and zero ohms to ground when the throttle
> is wide open.
> Steve Buchholz
> San Jose, CA (USA)
> > Anyone have a MAC-02 (yellow label - early) for
> > 1983 URQ?
> > I am reasonably confident that my FI issues (duty
> > cycle stuck @50%) are inside the ECU. According to
> > factory manual, the duty cycle should be around
> > 6% with the idle switch disconnected and the FT
> > triggered. Unfortunately, I get 75 with both idle
> > FT switches tripped. Having checked every wire
> > into the ECU, the diagnostic flowchart leads to
> > "Replace F/TCU."
> > So, what I am looking for is a MAC-02 to buy or to
> > borrow to isolate the problem. In the borrowing
> > I would pay postage both ways. Can anyone help me
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