[riberware]

I got a supposedly “new but open box” Bully Dog pyro gauge from eBay for my 1HD-T, and received the following parts:
1. pyro gauge
2. Thermocouple (probe with two wires inside a metal jacket)
3. Thermocouple wire lead??? Brown jacket with two wires inside, a plug on one end (that goes into the pyro gauge) and open on the other one.
4. Light + some misc. cables.



I have 2 questions:

1. To what exactly should I attach the thermocouple cable??? … I don’t see anything on the back of the gauge to plug those screws. I guess I should screw this end to the thermocouple wire lead?? BTW the seller said the wire from gauge to probe is cut about 3” short. This affects something???

2. How a 1/8” MPT x 1/8” compression adapter looks like?… I only received what is shown on the pictures + the gauge light, nothing more

Please check the pics

[TwoThirtyDirty]

Strip and crimp a couple of ring terminals to the non-plug end of the harness. Use the little bolts to connect the harness to the probe, red to red, yellow to yellow. Insulate the connection with split loom or fuel line or something. Plug into the guage. Maybe contact bullydog to see if harness length is critical. In the case of my JPI unit, harness can be cut to whatever length required.

Install for JPI Pyro might help

www.jpinstruments.com/slim_install_primary _rev 2.PDF

Compression fitting

Thermocouple Components-Accessories and Components for Manufacturing Thermocouples & RTD's

[riberware]

Thanks for your repply,

I just read the installation manual for the Bully Dog, says:

Do not shorten or extend the thermocouple wire. It is part of the calibration of your pyrometer. Coil the excess....blablabla



Your links were very helpful, I have a bad cable... it should look like this:

[TwoThirtyDirty]

That sux man. Sorry to hear it.

[TwoThirtyDirty]

Hey dood, I did a little more checking for ya and it seems to me that with only 3 inches missing from the harness, I would go ahead and crimp new ends to it and run it. The longer the harness, the more resistance and voltage drop the thermocouple signal is going to encounter. According page 3 of this...

www.turbodieselregister.com/EGT_EVAL.pdf

your gauge will be calibrated to take into account a given amount of resistance based on the harness length. With 3 inches missing, I would spectulate that the gauge would read only slightly hotter than actual EGT and if anything, you'll be monitoring on the safe side. My $.02 and worth about the same.

Again, just my opinion but I don't look at my pyro as gospel. For me it's just a reference point...I know what temperatures to expect on the flats and on the climbs. I know where it makes power (unmodified 3BII) and where it bogs. I use the EGT gauge to watch for out of the norm spikes on long climbs, headwinds, etc or if I ever get around to turbo-ing and turning up the fuel. Once I finish the install on my wife's 1hz, I'm not going to expect the numbers to be exactly the same.

HTHs

[riberware]

Waoo, great info...

Thanks for your 0.02...

[Dougal]

I wouldn't crimp new fittings to the thermocouple wire.

Those probes (K type) work by creating a tiny voltage at each point where two different metals meet. If you use different fittings (or even different coated fittings) than the original ones then you screw up the calibration of your gauge.
It is also very difficult to get a good and lasting connection between the fine lead wires and crimp connectors.

There are two methods which are guaranteed to work.
1. Buy mini K type connectors, these are yellow plastic with two metal prongs in them and are made of the right metals to not interfere with the calibration.
2. Strip both wires and crimp them together ensuring contact from wire to wire (i.e. not through the crimp sleeve).

My VDO kit came with ring terminals, the connection started to fail within a year, I crimped them together as a temporary measure but now have mini K type plugs so I can move things around and disconnect easily.

This is a lead with mini K type plugs and sockets. Industrial electricians have them.