is there such a device that i guess you would call it an engine diagnostic tool


a tool when you track down the sender for your oil pressure or cooling temp for your interior gauges that you can un plug the wire and plug in the hand held diagnostic tool and on the lcd display it will be abel to read the ohmage (ohms) from the sender and tell you the engien is at 220 degrees or oil pressure is at 42psi etc.....


i'm just wondering that this must exist somewhere to help garages.


i want it because i installed digital gauges and want for my own comfort to know they are reading correctly


any help would be great thanks

 

It's called an ohmmeter, and its a normal function of most multimeters.

 

Actually there is a diagnostic tool from Snap-on called the "MODIS" which will show you in great detail on a color screen where a specific sensor is, which wire to test, how to test it, and the best way to gain access to it. It will show you (in real time) your actual sensor output levels, from which you can compare these to diagnostic charts (already preprogrammed into the "MODIS") and determine if your sensor is T.U.

Or you can just use a DMM

 

your right about the DMM

but how about decoding it to tell me in PSI or temp

like 50ohms = 23psi etc.....
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also a DMM has two leads.

negative and positive

theres one wire from the senders

the senders r grounded so negative to the sender lead and postive to a 12v source?
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actually dumb question sry guys its ben a hile since i took electronics in high school.

but seriously 1 wire out of teh sender and two leads from the DMM how do i read the ohms across the sender?

 

The sender is a resistance to ground.

 

anyone know of a chart that says ok you got 15 ohms from the sender that means ______ in psi or in temp


because the ohm is just part of the puzzle

 

Most diagnostic charts I've seen will show you min/max values for a desired sender, and the desired value for a specified reading. I think the best books I have are a TPI swapper book I bought 20 years ago, and a GM manual for one of my c4 vettes

 

I can tell you how I am planning on verifying the accuracy of my analog guage...
by putting the sending unit in boiling water, I'll be able to get an acurate ohm reading at 212 Deg.
once I have that, I'll be able to get a variable resistor from Radio Shack. set it to the correct ohm reading and connect it from ground to the sender lead.
That way if my dash guage reads ... lets say 230... I'll know when to get worried becouse it is actually 212.
I was hoping to be able to adjust the guage... I looked on my spare instument cluster and don't know if it's possible. (do you think pulling the needle off and moving it would be accurate???)

Tony

 

i installed aftermarket digital gauges so thats why im trying to get them as accurate as possible.

already replaced the temp sender, gona need a little help doing the oil pressure sender.

the gauges have high and low ***** i can turn to get the right reading but i need to know what the correct reading is first.

 

if anybody has a site that will have the ohm chart that would be great im looking for one now and i guess i'll have to start looking for books if i come up empty

thanks for all the help guys

 

This will help you with the temp senders:
https://www.thirdgen.org/forums/atta...ase-ctsmat.gif

Lou

 

perfect thanks lou,

anyone have a ohm chart for the oil pressure sender?