How do you test/calibrate injectors

[johnl]

I really don't want to send my injectors out for testing, so is there a "shade tree" way to run them for a fixed period of time/stop watch into a graduated cylinder to determine/confirm their output?

[mech1nxh]

I really don't want to send my injectors out for testing, so is there a "shade tree" way to run them for a fixed period of time/stop watch into a graduated cylinder to determine/confirm their output?

Batch fire 180 deg crank, I used to disconnect the second injector
in the "loop" , and watch for < 5 psi drop from static fp (read on gauge)
in 5 seconds, and then repeat for the next injector .

Yes its Mcgyver, and tells you nothing about spray pattern, and assumes
pump, ck valve , and fpr are good, but hey its not totally redneck...lol

[johnl]

Wow. Thanks, I need to envision this -

Do I lay them out disconnected from the intake manifold, connected to the fuel rail but only one connected to the harness, and then crank the engine for a fixed time, while allowing the fuel from the one selected to spray into a graduated cylinder?

[mech1nxh]

sorry, late getting back to this.

the above test, vehicle is assembled, and uses gauge pressure drop
as an "indicator" of a flow issue (be it mechanical or electrical)
and key on engine off

But I don't see why your thought would not work, just be SUPER
SUPER careful....(ign totally dead, not "o" ring leaks, retainer clips pristeen...)

[87glhs232]

So what your saying is your not measuring fuel in liquid volume, rather using pressure drop as an indicator. So if you get 3 injectors that show a pressure drop of 5 psi and one that shows 2 or 3 psi then you know you have an issue.

**Those numbers are completely random and are used only as an example

[johnl]

OK, that's what you said, thanks, should'a just read what you said. Thanks

[mech1nxh]

So what your saying is your not measuring fuel in liquid volume, rather using pressure drop as an indicator. So if you get 3 injectors that show a pressure drop of 5 psi and one that shows 2 or 3 psi then you know you have an issue.

**Those numbers are completely random and are used only as an example

Correct.....But see below, Johnl's idea is excellent!! IMHO


OK, that's what you said, thanks, should'a just read what you said. Thanks

And thank you! I never thought about pulling the rail and doing a "live"
(at least at cranking speed/pulse width) test. cool thought!

Scenario... miss develops after "hot runs",( extreme caution would be needed
during testing...hot engine, fuel vapors, blah blah ..insert board disclaimer)
but I have seen a lot of weak solenoids tend to get lazy after heat >85% duty cycle...
Coil disabled, so there is still an rpm/inj signal, plugs out and test.

Now of course we are not using a temperature stable inj test fluid for the
test, but your idea could get a win ...:nod:

[BadAssPerformance]

The Mopar Performacne injectors were sold in sets of 4 because they were supposed to be 'matched sets'.

To check them to see if they are good/bad you can just use a Ohm meter and se eif they each give you the same number. Not by any means the correct way to measure impedenmce, but if the Ohm meter reads 'OL' (overload) or 0.0 (zero) then you know its not good...

[turbovanman²]

Search for an injector tester, IE its a box that hooks up the battery and then you plug it in the injector. You can change the PW to a few settings or full on. They should be on Ebay or a local parts store for under $100.

So you'll unhook the fuel line from the car, lay out the fuel rail, unhook the electrical connectors, jump the coil + terminal and aim the nozzles into a cup or ? then go one by one and activate each injector looking at the spray pattern etc. I have found many a bad injector doing this.