How to interpret Injector testing result?

Is this a trick question?
I'm not qualified to say how close they should all match.
Looks like clogged injectors that need cleaning on 3rd and maybe 4th vials.
Were they leaking after shutoff?
ps California would prefer they all match the 3rd vial

 

First I would switch all positions to confirm the lagging injector(s) follow.

(and I assume they would, but still).

Maybe they will start to balance out once you run enough solvent through them

 

The volumes seem to be pretty consistent, a six percent spread should not be the end of the world. Were all of the injectors this consistent?

The injectors should be giving an even conical type shape fan of atomised fuel spray, if there is a stream of fuel or differences in between injectors then there is likely a problem. The degree of atomisation depends on the operating pressure and nozzle arrangement, YouTube should give some insight.

Given what appears to be fairly even flow, the injectors may not be the cause of the glowing cats. Have you checked for vacuum leaks and header temperatures yet?

 

If the spray patterns are the same and you don’t have leaks I’d guess your hot cat issue is from an intermittent spark issue where you’re not getting combustion and fuel is getting into the cats. Check the plugs and electrical components. If it’s consistent you should be able to diagnose easily by checking fro spark, if it’s intermittment try switching components and see if you can get the issue to move.

 

The vacuum leaks will be an issue in the inlets to the cylinders after the airflow meter. Could be failing gaskets or a poor seal from something removed during a service. It can also be specific for certain items where wear can occur like throttle blades etc. a good way to test is spraying carb cleaner around potential leak areas when the motor is runnning in open circuit, ie before it is up to operating temperature and starts controlling fuel addition with the O2 sensors. A vacuum leak will typically give a faster idle as the carb cleaner is ingested. A smoke test is a safer alternative, ie the smoke is drawn into the leak when wafted past.

A dyno is a much better and safer way of diagnosing issues that are manifesting themselves during driving situations, but determining the temperatures of the cats and individual header pipes can also give an important insight into problem areas.

 

Is this a simple "injector held constantly wide open" EFI injector tester, or one that supplies a PWM signal and can be checked at different flow rates (and checks the "dynamics" of the injector opening-closing action)?

 

There is a significant difference in flow rate in the one injector if the time interval was really kept constant. Here are some real results from a company that does this for a living. These are from my V12 with near identical injectors and Motronic 7.1.1 vs the 360's 7.3.


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