[V8] Oxygen sensor.
dsaad at icehouse.net
dsaad at icehouse.net
Fri Jan 30 13:24:19 EST 2004
To solve for/prevent that problem I used the ground side of the heater wires.
(one of the heater wires) Seems to work fine.
Quoting "Buchholz, Steven" <Steven.Buchholz at kla-tencor.com>:
> ... you should be very careful when trying to consider where to connect
> extra ground lead on the 4-wire OXS. It is very easy to create a ground
> loop and end up making things worse than with the factory 3-wire. When
> did the engine swap on #2 I learned that all of the engine wiring goes
> directly through a wiring harness that sits below the throttle linkage
> the back of the engine ... this includes ground wires that go to the
> Let's say you had a situation where the exhaust crossover pipe wasn't
> connected to the engine ground ... now the OXS signal can get altered by
> difference in ground voltage between where you have the OXS grounded and
> actual engine block. Remember that tenths of a volt can make a
> in this sort of signal, and when you consider the high ground currents
> between the engine block and the body of the car it isn't that hard to
> imagine tenths of a volt changes in the ground reference. Grounding in
> modern car is not as simple as in the old days when all you needed was
> for the starter and lights!
> I fully agree that you may well realize an improvement in the OXS'
> signal to
> the ECU by switching to a 4-wire OXS, but you should think carefully
> the grounding. My recommendation would be to find the ground lugs below
> left distributor and attach the fourth wire to one of the two ground
> there on the back of the engine block.
> Final comment ... I got a non-Bosch 3-wire universal OXS from my BiL's
> a while back and installed it on #344. Overall I'd say that it works
> but there is a point a couple of minutes after a cold start where the
> runs poorly for 15 seconds or so ... I suspect this to be due to the ECU
> thinking the OXS is warmed up when in fact it has not yet ... I will not
> install another OXS in the car that is not made by Bosch and have the
> general design as the standard part ...
> Steve B.
> San Jose, Kaleefohnia (USA)
> > I also use a Ford 4-wire and it works fine. I like the extra
> > ground wire as I
> > think it helps give a more consistent reading and the
> > Motronic seems pretty sensitive to this.
> > If you use a 3-wire it is a good idea to make sure the
> > exhaust pipe is well grounded.
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