how to ohm test fuel injectors?
06-07-2010, 01:27 PM
#1
Drifting
Thread Starter
how to ohm test fuel injectors?
I have an 86 with 84k miles on it and have done a lot of suspension and interior work and now I want to learn how to do some of the engine work. Specifically, how to test the fuel injectors. I read a lot of the threads here so I can learn and I see people talking about testing the injectors. How do you do this. I have the multimeter tester. Where do you place the probes, what setting do you put the tester on and what am I looking for. I am a total rookie so I guess I need the most simplistic answer. The car runs good, I am just curious and want to learn more about this. I am trying to go through the engine and check for vacuum leaks, compression, etc. Any help would be greatly appreciated. Thanks
06-07-2010, 01:57 PM
#2
Pro
Member Since: Dec 2009
Posts: 502
Likes: 0
Received 0 Likes
on
0 Posts
Read the sticky up top by Jon of FIC.
Note: there is not away to test a injector that is stuck closed, one stuck open is pretty easy to check w/fuel pressure gauge and checking plugs for fuel fouling.
Note: there is not away to test a injector that is stuck closed, one stuck open is pretty easy to check w/fuel pressure gauge and checking plugs for fuel fouling.
Here is a good write-up and video from Jon Banner @ FIC. Check it out....
06-07-2010, 04:23 PM
#4
Le Mans Master
Member Since: Jun 2006
Location: One day you're a Comet...the next day you're dust... Arkansas
Posts: 5,642
Likes: 0
Received 5 Likes
on
5 Posts
Don't set your meter at 2000 ohms like Jon says you will be off by a factor of 10, set it at 200 ohms. That should give you the proper resolution. IIRC stock injectors will measure 16.0 to 16.5 ohms if the windings are good but that varies by Manf.
06-07-2010, 11:34 PM
#7
Team Owner
Member Since: Mar 2001
Location: Cincinnati, Oh USA
Posts: 53,917
Likes: 0
Received 26 Likes
on
23 Posts
An ohmeter will only find gross coil errors. Injector coils receive pulses of current and a turn to turn short will prevent them from working, but an ohmeter cannot see a turn to turn short. The instrument to use to properly test the injector coil is an impedance bridge which measures the inductance and the Q of the coil. A turn to turn short can easily be found with an impedance bridge. I found one in my 87 that had the exact d.c. resistance as all the others but it measured 1/2 the inductance and 1/2 the Q as the other injectors.
The following users liked this post:
Damon 86' Auto C4 (11-27-2023)
