Eric F

I have Autometer UltraLite electrical oil pressure and water temperature gauges that I need some information about installing in the Protege. Does anyone know the input voltage range of the Autometer electrical gauges and the output voltage ranges of the stock sending units? Can I use the stock sending units with the Autometer gauges and/or the Autometer sending units with the stock gauges? If not, has anyone come up with a method of mounting both sending units? I'm assuming it's necessary to keep the stock gauges functional to prevent a check engine light, correct?

mazdaspeedwest

you sir, need an E-FSM i wish i could help, i only have a 1st gen E-FSM. I think the factory electrical manual is the only answer. but didn't the guages come with some sort of specs?

Eric F

Darryl, good point. I have the manuals, and I suppose I might be able to get the stock sending units output voltage range from them, although I'm not so sure. The gauges didn't have anything that detailed with them. I'm wondering if anyone has experience with this. I'd like to know which sending units are likely to be more accurate. My guess would be the Autometer units. The stock water temperature sending unit is purposely calibrated to be less sensitive around normal operating temperature so the gauge doesn't move much once the car warms up. I guess people get scared if they see the gauge fluctuate at all. If so, I'm going to need adapters to mount the Autometer sending units. I'm pretty certain I need to keep the stock oil pressure idiot light and water temperature gauges connected to prevent a check engine light. Anyone know about any of this for sure, or do I have to do it the hard way?

mazdaspeedwest

sorry bud, that ones just not in the experience banks. Although, i would say that with OBD2, the factory gauges may have to be connected or fooled into thinking they are.

true on the accuracy thing too, my temp needle hasn't moved in 12 years, it sticks to the same mid level spot all day long....even on the long hot drive to Las Vegas. Gotta love it's consistency though

I've never seen my oil light come on, except when starting.

Metallargy

Some gauges utilize independent one-wire sensors not used by the PCM ... and they won't set off the CEL if disconnected.
Dummy lights are good examples.

I'm not familiar enough with Proteges, so I can't tell you which are which.


www.autometer.com has downloadable pdf files that might prove to be useful to you.

Generally it's best to use the provided sensor w/aftermarket gauges because they're properly calibrated. If you're installing a gauge that'll give you more info than a dummy light, then the sensor for the light won't work for the gauge.
A lot of times the factory sensors (single wires associated w/stock gauges) aren't that accurate to begin with - if they're too accurate, there'd be several people at the dealership complaining about sweeping gauges all of the time.
A/F gauges are best tapped off of the PCM pinout for the O2 signals, or used with new sensors tapped into the stock exhaust (get a bung welded on).

In some cases, a new hole can be added next to the stock sensor, or the measured medium can be split between the two sensors (such as threading in an adapter into a stock sensor hole, then threading the stock & aftermarket sensors into that).

HTH