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View Full Version : is their an air/fuel gauge for diesels?



CJ_4
12-26-2005, 17:21
i recently bought an air/fuel gauge for my 6.5L TD, not thinking about certain gauges not working on diesels like they do on gassers tongue.gif , the instructions had a warning to not use it on diesels b/c of permanent oxygen sensor damage, do they make air/fuel ratio gauges for diesels?

john8662
12-26-2005, 21:17
No need for A/F ratio gauge on a diesel.

Diesel engines run lean, except when running rich. for determining when a Diesel is running rich, you just look in your rear view mirror, the BLACK smoke is unburnt fuel.

The gauges you NEED on a 6.5 are:

Pyrometer (Exhaust Gas Temp)
Boost Gauge (see if the turbo is making pressure)

The destructions that came with the gauge are correct, a diesel will damage the Oxygen sensor, it will be filled with sut.

GMCfourX4
12-27-2005, 10:25
Something else to keep in mind. If memory serves me correctly, a diesel will run as lean as 125:1 at idle (I think a truck diesel is usually something like 90:1, but I could be wrong) and will run as rich as 25:1 at WOT, thereabouts. Again, I could be remembering the #s wrong, but either way, its always MUCH leaner than a gas motor. Remember, there are no throttle plates on a diesel, so it's always drawing as much air as it can, the amount of fuel vs. engine load is the sole factor driving engine speed.

-Chris

CJ_4
12-27-2005, 18:07
THANKS FOR THE ADVICE. I'M NEW TO DIESELS SO I WASN'T AWARE THAT THEY ALWAYS RUN LEAN. I WAS THINKING I HAD SEEN AN AIR/FUEL ON A DIESEL BEFORE, BUT I COULD BE WRONG. I ALREADY GOT THE PYROMETER AND A BOOST/VACUUM GAUGE, BUT I GOT A THREE GAUGE POD COMIN DOWN THE PILLAR, I'LL JUST FIND A DIFFERENT GAUGE TO TAKE THE AIR/FUEL'S PLACE

rjschoolcraft
12-27-2005, 18:17
Trans temp or engine oil temp are good suggestions.

CJ_4
12-28-2005, 15:57
Originally posted by ronniejoe:
Trans temp or engine oil temp are good suggestions. thanks for the suggestions, they were a couple of the ones i was considering, i prolly will go with the oil temp since i dont really tow, except i'll prolly tow my boat this summer, we normally tow it with my dad's ram, but i just got my truck this fall though

CJ_4
12-29-2005, 18:21
one last question. i decided to go with the oil temperature gauge. they have a 100-250 degrees, and a 140-300 degrees. which one should i go with. i'm not sure what is my engine's normal oil temp is. it's a 6.5L

rjschoolcraft
12-29-2005, 18:32
Go with 140-300.

CJ_4
12-29-2005, 18:53
Originally posted by ronniejoe:
Go with 140-300. aight. thanks