Homemade Noid Light for testing Fuel Injectors.

[xekon]

I don't own a noid light, but I had an old LED flashlight.

I have read that I can use an LED bulb and a resistor to make a noid light for testing the fuel injector system on a vehicle

I have a fairly good amount of experience soldering, from repairing wires and connectors on small electronics and wiring harness.

I know the resistor needs to go to the positive side of the bulb.

The bulb I have is 1.5V 0.2W , what would be the proper size resistor to use?

Did a little more research and it looks like most LEDs use around 20ma or 0.020 amps so is this correct:

13v / 0.020 amps = 650 ohm resistor?

is there anything else I need to consider?

One thing I was thinking is I could use a diode on the negative side to make sure if somebody accidently hooks it up with reverse polarity they dont fry the bulb, what size diode should I use?

 

[jcurrie]

the noid light wont test the injector it will just tell you that the injector is getting a pulse to test the injector it self you realy need a injector test set up, unless its a throttle body then you can use a timing light to see the spray pattern, is the engine missing or you just want to test wireing ?as far as the LED sounds right to me

jc

 

[xekon]

Well we are having trouble getting the vehicle to start, we bought it not running.

I finished the noid light with the LED, and it worked great, determined that when #1 injector is hooked up none of the injectors are firing so I think there is an issue at #1 injector.

We though that we could just leave the #1 injector unplugged and the vehicle would start right up at that point running on only 3 cylinders of coarse. Unfortunately it did not start, if we have fuel, compression, and spark it should have. we have compression and spark.

The only thing left to test that I can think of is weather or not it has enough fuel pressure. We are going to test that tomorrow.

 

[jcurrie]

what make, model and year ?
do you have access to a scan tool or even a code reader?
jc

 

[xekon]

Thanks for the replies.

I do have a code reader but its for OBD2.

This vehicle is a 1995 Suzuki Sidekick. I have put a pin into the connector that's under the hood to retrieve the codes from the light on the instrument cluster, and all I get is code "12" which from what I understand means everything is "OK"

 

[jcurrie]

one of the guys i worked with bought one 1993 of them about 6 years back with the same problem we finaly run problem down to a bad ground on the computer box run a wire from box to neg post and cured problem. code 12 if the same as GM means no crank rotation normal if engine is not running.
jc

 

[xekon]

GOING TO TRY THIS TODAY! Thank you!

 

[badbrad]

Hi, did you get this vehicle running or not? try a direct earth to injectors also if possible as could be a break in wire or check wires with multimeter if you have one on ohm setting.

Also how did you make the noid light, was it how you asked and did you add a diode?