Thermocouple/firewall planning ?

[Larry DeCamp]

I need to decide if miniature TC plugs at the firewall are reliable vs. hard wire through the firewall and disconnect EGT & CHT sensors for engine removal. Rainer ( MGL ) says copper extensions are acceptable as long as the cold junctions ( solder joints ) are the same temp. This makes a D-SUB connector at the firewall viable. Any comments ???........Larry

[aerhed]

I don't know how "approved" it is, but I ran all 12 thermocouples to one CPC male with a bulkhead connector on firewall. Gold pins and continued inside with the k-wire to the RDAC on sub panel. Temps were perfect and stable on an Odyssey.

[Mich48041]

Rainer ( MGL ) says copper extensions are acceptable as long as the cold junctions ( solder joints ) are the same temp.

True, but the fewer splices the better. 99 percent of electrical problems are poor connections. Keeping those connections and terminations to a minimum will lessen the chances of failures. A non-existent splice can not fail. The installer must weigh the convenience of having a splice against the risk of the splice causing future problems.
Joe Gores

[Bill.Peyton]

I agree with the above ! Never add a connector unless there is no way to do without. Both the egt and cht probes already have connections at the sensor, so from a serviceability standpoint, nothing is gained by a firewall connection.