plattted

What is the O H M specs for fuel injectors on a 1994/ 5.7L engine?

shoebox

12 ohms

plattted

Thank you for the reply.
Is 2 OHMs above or below that 12 OHMs allowed as a variable?

maybe2fast

I think the range is 12-17ohms. Typically you want them close to each other

plattted

I have 6 that range 14.2-14.3.
One at 14.6.
One at 13.7. Just wondering if I should change the 14.6 and the 13.7 injectors. I tried cleaning them but these two remain out of range from the rest in spite of the cleaning. Recently I installed new lifters and plugs but still have a minor misfire/rough at low speeds and wondering if this could part of my problem.

Ted

shoebox

IDK (not an expert on this), but I would not consider that significant.

Injuneer

The 94 shop manual writeup for DTC 18 indicates that a resistance below 11.6 ohms is considered a faulty injector. As I recall, the upper limit is about 16 ohms.

maybe2fast

I agree with the Gents above, not the problem

97WS6SCharged

You're talking about half an ohm difference. With OBD1 technology that is not enough to make a difference. If you take any set of injectors and ohm them they will not all read the same. The injectors seem to be within acceptable tolerances; if you're going to diagnose your misfire you really need to have a scanner handy to see what the PCM is doing when the mishap occurs. Otherwise you're just grasping at straws.

plattted

Scanner,YES, that's the thing to use!

Thanks, Ted

Injuneer

If the injectors or the wiring were outside of electrical spec, the PCM would have set DTC 18. That one does not turn on the SES light.

plattted

I'll continue my diagnosis...

Fatdog2

Would this be the same for the 93? I measured my injectors today and they read like this.
#8 cyl.-13.2
#6 cyl.-13.2
#4 cyl.-13.2
#2 cyl.-13.2
#7 cyl.-13.3
#5 cyl.-12.8
#3 cyl.-13.1
#1 cyl.-13.2
So the pass side seems steady but the drivers side seems to vary some.I'm getting ready to pull all the injectors for cleaning and new gasket (o-rings) install and was wondering.Many thanks in advance.

Injuneer

The inrush of current develops the magnetic field that opens the injector. The resistance affects how fast the injector opens, but once it's open, resistance is no longer a factor. Lower resistance means higher current. Higher current means faster opening. But you don't want the resistance so low that the current excedes the amp capacity of the injector driver in the PCM.

In practice, the tiny change in opening speed due to differing resistance has very little impact on the amount of fuel injected. Impact is greatest at idle. Voltage also affects current, and the system voltage is likely to have a larger effect on the rate at which the injector opens, but the offset table compensates for that.

Bottom line after all the jumbo-jumbo - don't worry about the small differences in resistance.

Fatdog2

Again, great info.Thanks.