multimeter question

[81SPIDERMATT]

getting ready to chase down an issue with the car running rich.. (gas smell from exhaust) .... i understand almost everything ... but when it comes to ohms i get stupid fast.... this is my meter and wondering what setting to use for instance checking the water temp sensor on the coolant T .... i know that i check it at the T and then again at the ecu ... i know that the meter will be set to the lower left ohm ranges ... just not which one.... thanks..... Matt .... also will the setting suggested work for all my resistance measurements ???

[ORFORD2004]

200 means 0 to 200 ohms
2000 means 0 to 2000 ohms
You start at 200, if you read 1, your scale is too low. You raise the scale untill you have a reading.

[azruss]

your meter probably only reads 4 digits or so, so the higher the ohm setting, the less accuracy you will see. Thus you want the setting to be as close on the high side of what you are trying to read. if you think you are going to get something in the 350 ohm setting, you need to set the meter on 2000. It doesnt hurt to switch it back and forth. if the ohms are too high for the setting, the meter will tell you so with some cryptic message. Remember when you are measuring ohms, there cant be any power to the circuit...this will fry your meter. If you set it on the speaker icon, you can test for an open circuit. It will beep when the circuit is complete. for instance, you can test a light bulb on this setting, connecting one wire to the base connection and the other to the side. If it beeps the bulb is good.

[81SPIDERMATT]

thank you gentlemen ..... gonna have to read over things again.... thought some of the tests were while the car is running and getting to temp.... dont want to fry my meter

[azruss]

your cold water sensor just changes resistance with coolant temp. It is not powered with 12v. So as the car heats up, you can disconnect the plug and measure the resistance of the sensor, not the plug. Many times, it is the plug that is the problem. broken wire where it bends. Here is where you need to check for an open circuit. If you know where the other end plugs in to the ecu, you can check continuity in that wire. The shade tree was is to wiggle the wire at the plug while the car is running and see if it clears up.

[81SPIDERMATT]

that makes sense.. i was reading it as check the sensor... then check at ecu .... was thinking i would have to warm up car once for sensor ... let it cool down and then do it again at the ecu..... ..... also will the car run at all with ecu unplugged??? .... or is there a way to probe it while connected.... stupid @@#$%@$ back is killing me and have not climbed in the car as of yet ...still doing my reseearch

[azruss]

I would invest in a resistor as described and plug that in to the harness. If that makes a big difference then you need to take a close look at the sensor and associated hoses. If it doesnt make any difference at all, then you need to look at the harness between the sensor and the ecu.