"Bernd D. Ratsch" <fasstdak@hotmail.com> wrote:
: jon@dakota-truck.net wrote:
>: "Bernd D. Ratsch" <fasstdak@hotmail.com> wrote:
>: : Try the CTS first (do not use thread sealer - they're a tapered fit and
>: use
>: : the manifold as a ground connection).
>: [...]
>
>
>: Jay's truck is a '97 so the coolant temp sensor doesn't use the
>: manifold as a ground. On '96 and earlier Magnum powered Daks,
>: there were 2 coolant temp sensors; one for the computer and one
>: for the gauge in the cab. You would be correct in referring to
>: the gauge temp sensor on a '96 and earlier truck, since that
>: sensor did indeed use the intake manifold for its ground, but
>: the PCM's coolant temp sensor has always provided its own ground.
>: So, short story shorter, there would be no grounding problems if Jay were to
>: use thread sealant on his '97s coolant temp sensor.
: We've seen problems with the signal when they had sealer on them (plus, they
: come with a conductive sealer from the factory). This applies up to '05
: models.
Hmmm... Ok, that statement pegged the needle on the ol' "does
not compute" meter. :-) It didn't make any sense to me why Dodge
would have gone through all the trouble of providing a separate
ground path if they could just use the engine ground through the
body of the sensor. There would also be a cost savings if the
ground was through the body of the sensor since they could have
just used the same 1 wire sensor they were already purchasing to
use with the in-cab gauge, and save money via the increased quantity
discount since they now only need to buy one type of sensor (and
one type of wiring harness connector, since those are different too.)
However, rather than just posting without any evidence to back
up my theory, I took some time today to pull the 2 wire coolant
sensors in my '96 Dakota and my '92 Ram. As I suspected, in both
cases, neither pin of the sensor had continuity with the body of
the sensor. As such, the only possible path for the PCM to read
the resistance of the sensor is via the wiring harness connected
to the two pins on the sensor. Basically, this means that it
is completely impossible for the ground state of the body of the
sensor to have any effect whatsoever on the signal to the computer.
(Unless of course something is broken, and even then, it would
take quite an interesting series of malfunctions and improbabilities
to set up a condition whereby grounding the body of the sensor
would actually allow the PCM to receive a better signal than
before.) If by some outside chance this were to happen and it
was discovered that installing one of these 2 wire sensors with
sealant was causing a problem with the signal, then something is
quite broken and needs to be repaired; the solution is not to
remove the sealant and call it a day. :-) If you have seen
problems with the signal from a coolant temp sensor when using
sealant, I can only assume that you may be confusing it with a
1 wire sensor or mebbe you were working on a Ford or something,
'cause it sure wasn't a Magnum engine's 2 wire CTS. :-)
BTW, when I re-installed my 2 wire coolant temp sensors
tonight, I used teflon tape on 'em, and can wholeheartedly
recommend to anyone else who might be inclined to do so to
go ahead and wrap those suckers up, 'cause the signal to
the PCM will still be five by five. ;-)
--
-Jon-
.-- Jon Steiger ---- jon@dakota-truck.net or jon@jonsteiger.com --.
| 1970 Barracuda - 1990 Dakota 'vert - 1992 Ram 4x4 - 1996 Dakota |
| 1996 Intruder 1400 - 1996 Kolb FireFly - 2001 Ram QC 3500 CTD |
`------------------------------------ http://www.jonsteiger.com --'
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