Chapman88SR5

I am trying to test the #1 fuel injector on a 22RE.

My OHM Meter has a dial on the front (as most of them do). The FSM says that the resistance for the injector should be 13.4-14.2. My question is; what do I set the dial to? The OHM Meter looks like this

Should the Dial be turned on 20k or 20m?

Also I have turned it to both and still do not get an accurate reading. The numbers jump or just stay a blank screen.

wjwerdna

13.4-14.2 what? (units?)
k, M, m... etc are just SI units for the number of zeros

20 k is 20000
the 200 is for 0-200
the 2000 for 0-2000
20k for 0-20000

go the smallest without going over max

4Crawler

iTrader: (3)

See the following page fr some tips:
http://www.4crawler.com/4x4/CheapTri...oUseAnOhmMeter

The resistance scales set the maximum resistance that can be measured and displayed, so for the most accuracy, you want to use the smallest range that covers the expected resistance value you are trying to measure (since the meter display only has a few digits, 3-1/2 in your case). For example if you select the 20M (M=million) you can measure up to 20,000,000 ohms, but the display will read 0.00 up to 19.99 milion ohms and the difference between say 0.00 and 0.01 million ohms is actually 10,000 ohms. If you go to the 20K (K=1000) range, the difference between 0.00K and 0.01K is 10 ohms. Neither of those two scales would give a lot of resolution trying to read a 13-14 ohm value. Ideally, there is a 20 or 200 or 2000 ohm scale on the meter that will give you a more accurate reading. If so, use the lowest range that is at least big enough to cover a 14 ohm reading.

Note that an injector coil (what you are measuring) is basically a big spool of wire around an iron core, so it is really more of an inductor rather than a resistor. Inductors give funky readings to DC ohms, in that they slowly build up a current (from the meter) over a period of time, so the readings will vary as the probes are connected. It will start out high then drop to a lower resistance over time.

The "exact" resistance is likely not terribly important, since what you are really checking for is that the injector is not shorted internally (a resistance reading very much lower than 13 ohms) or open (a resistance very much higher than 14 ohms - such as infinity - due to an internally broken wire).

wjwerdna

yep... 4crawler explained well what I didnt feel like doing , and added a real good point about the inductor, fluctuation, and basic range of what you are looking for

Chapman88SR5

4crawler to the rescue again!