Does anyone have some fuel injectors they can Ohm test for a question?

I'm looking for someone who has some old 3.4L Phase I (95-98) or Phase II (99-04) they can check for an Ohm reading.

The FSM for my 99 model states
Resistance: Approx. 13.8 Ohms at 20°C (68°F)
If the resistance is not as specified, replace the injector.

I tested the old Phase I injectors from the 70,000-mile replacement engine and they are coming up in the 16s and low 17s.

The new Phase II injectors that I just purchased are in the 15s.

I'm curious to see if anyone has Ohm tested their stock OEM injectors and possibly some new replacements?

Note: The only injectors that I've seen that test PERFECTLY and evenly across multiple injectors in both Ohm and Flow testing are BWD "Black Dot" or top shelf new injectors from Deatschwerks in OKC. Those are individually pre-tested in both Ohm and Flow before they get the Black Label for use in twin-turbo applications where everything must be absolutely perfect.

The injectors I'm most familiar with have a tolerance range.

I'm trying to establish a real-world benchmark for acceptable ranges.

 

Fuel Injector unless your working on something really strange

First I venture your meter is not calibrated.

Not sure just where your getting 13.8 W do you mean Ohms ??

As a rule of thumb 12 to 16 ohms

The few used ones I had laying around they measured 13 14 and another at 14 Ohms

Granted things might be a little corroded I think any you don`t get a open coil are good

your only measuring the resistance of the coil

 

That's right. The Ohm symbol converted to a W when I pasted it from the FSM PDF. Corrected the title. Just had a plumbing problem with the kitchen sink.

I agree with the 12 to 16 Ohm rule. I've seen coils fail and show 0 resistance.

I'm using one of the freebee Harbor Freight VOMs. I suspect it might be off.

The digital display on my good VOM started breaking up and I had to pitch it. I think I'm going to pick up a better VOM for this test.

 

A open circuit does not read 0 it reads infinity depending on the meter it will just read OL

0 means no resistance

 

This is a sign that they're getting old, it's pretty common on Denso injectors for the coil resistance to climb as they age out. They're probably due for a new set if your reading are accurate. @SilverGhost ohmd his our recently and they were really close to stock spec still.

 

^^^ I stand corrected.

Meanwhile, I figured out the Ohm differences.

The FSM says Resistance: Approx. 13.8 Ohms at 20°C (68°F). The test needs to be run at (68°F).

I put the injectors in the freezer for an hour, retested and got much lower Ohm readings -- like below 12.0.

Then as the injectors started to warm up in the sun, the reading started climbing.

This morning, I had the injectors sitting in the sun. That messed up my test results.

After a retest, all is good. The last time I worked with injectors I think it was October in cooler weather.

I would have never thought that injector temperature makes a difference.

Thank you guys for the quick response.

 

That's right.

 

Yes the temp matters. When I tested my injectors right when I pulled them they were around 13.2-13.3. WhichHunter got different results.

 

That's a nice report. Good shop.

 

Yes, unless it’s a semiconductor, more heat=more resistance.

 

I'm trying to learn some about the resistance testing of my coils. I have all six of my old ones out and on the table. Not sure where to set the multimeter at to get the results you are getting but . ... I set it at "full" thats with not numbers on it. When I test them I get .04-.06-.06-.06-.07 and I got one that had no reading at all. Granted these injectors have about 240th miles on them..likely. So.. I'm figuring the one with no reading was bad? but how to I get the 12 ohms. where do I set the meter? I see settings like 200-2000 -200K-2000K and one setting that has not numbers. That's the one I used and got the reading mentioned.

 

Without knowing just what meter you have pretty hard to tell you what range.

Is it Analog or Digital ?? With my digital meter I can use 200 ohms or 2000 ohms

You want the lowest scale

I would think that would work for you.

Do you have any good bare speakers handy the resistance is most often printed on them that should give you an idea what range to set your meter

Worse case find a users manual for your meter.

 

Something I just thought of if your not comfortable with your Meter and using it for every function.

Before schooling I know I would wonder is this the correct reading or did I do something wrong to come up with a far different value.

I tend to forget those days long ago

 

Set your meter to so it will read between 0 and 50 to 100 ohms.

Last year when I checked my injectors (1998 3.4l engine) 5 of them read around 15 ohms and the 6th one read about 24 ohms. That was the one that my CEL indicated had a problem. You don't need to remove them to check them, just need to remove their connectors. Just remember that all of them should read within a couple of ohms of each other.

I replaced all of them with refurbished ones (for about $180 shipped from California). Hope this helps!

 

I just measured the resistance on my original 1999 fuel injectors with a nice Fluke 114 multi-meter at 76 deg. F and I got 13.9, 13.9, 13.8, 13.9, 13.7, 13.8. I didn't measure the new/refurbished ones before installing.