502 MPI Alarm System Questions??
 

Bought 1999 Fountain with 502mpi mags. Livorsi gauges were installed and the alarm system was not hooked up so I have to constantly look at my gauges to make sure everything is okay. I noticed this after buying...

So my question is, does the alarm system for the high water temperature and low oil pressure read from the old stock gauges that had warning lights or does it read from the ECM?

I've done a search and cannot come to a conclusion. I'm new to these motors so I apologize if I'm sounding dumb.

It reads off separate sensors on the engine. It is not related to the guages at all.

Thanks. Next question is, is this one wire? What color would it be?

My my alarm lights and buzzer wires are cut. Can't find what use to connect them so I'll run a new one if I have to. My guess is that it was alarming all the time and they took the easy way out instead of fixing the problem.

this should help

Thanks. I found that on google...16 would seem to be my answer but it goes to the ECM. Not sure where it goes to the dash.

Your previous guage warning lights were part of the guage. The warning lights go off based on the guage reading only.
The Merc alarm wires are usually Tan with a Blue stripe. The diagram above shows Tan with White stripe.

That is the engine harness above. It connects to dash harness via the 10 pin Cannon Plug.

That helps out a lot. In saying that, the Merc alarm wire monitors what? Drive oil only?

low oil pressure sender to the ECM ( most install where the oil pressure sender for the dash gauge is ) and drive oil level

Low oil psi, high water temp, low drive lube

and general warning 2 -- if a transmission is in the mix.

also certain calibrations can set a horn --- 1 is soft alarm = 1 sec second on / 3 seconds off below 3000 rpms and a hard alarm = constant warning alarm above 3000 rpms when a active code is detected.

Thanks everyone for the replies. Very helpful. Actually found the wires. They were tucked away good. Tested with the key on (not started so low oil pressure should make it alarm) and didn't have power. Thinking harder about it, maybe such indicators make the alarm go to ground instead of having 12volts? So tomorrow I'll test for a ground instead. If that don't work, not sure what my next step is.

I'm very OCD and like to have everything working correctly.

If the alarm wire is grounded it will set off the audible alarm.
I had an alarm wire that was spliced come apart. The bare wire making contact with the intake manifold was setting off the alarm.

Good news it's grounded only when the key is on. I'm going to buy muffs this week to make sure with oil pressure, it functions properly.