Tested My CIS Injectors today

[Pat S]

After rebuilding my engine this summer, I moved on to the CIS system. I replaced all the gaskets, adjust CO levels, Idle, Timing etc. But I never checked the injectors until today. Everything was running well so I had no reason to think they were bad, but I wanted to check them.

So, following instructions from one of the many CIS books I've read, I pulled them all and placed them into plastic containers that wouldn't melt in gas. I actually used some condiment squirt containers I got for 1.25 each from Target. I drilled a hole in the top of each, then inserted the squirter (i have nylon fuel lines so that made it very easy) .

I placed the fire extinguisher handy then turn the key to make the pump run.

Then I lifted the air sensor plate to make the injectors squirt. All the injectors looked great. All produced a nice fairly even cone shaped squirt.

Then after I'd guess 15-20 seconds of running them with the plate at full height I shut down the pump and compared the amounts of fluid in each container.

As you can see below they were all very close. 4 looks just very slightly lean, and 5 looks a bit rich, but they are all very close in amounts. Anyone think otherwise?

So it was a pretty cool 10 minute test that makes me feel better when I hold that throttle to the floor.

First pic is just a raw pick.

[Pat S]

Second one has two parallel lines drawn on the bottom of the containers and what I guessed as the average.


Pat

[350HP930]

As long as a visual inpection of the spray pattern looks good your injectors and distributor appear to be in good shape.

[azasadny]

Pat,

That looks pretty good to me.

[Pat S]

Yeah, I was very please to see them all spray a nice cone shape. I assume they are 30 years old since I have nothing to document otherwise. I soaked them in techron for a few weeks during the rebuild process and have run a few tanks more through them.

Pat

[chicago_82sc]

Pat:

Terrific test. I have some questions on my injectors and have planned to look at them over the winter. Your test is a great model to follow. Simple but gets the job done.

Bob

[PHILIP315]

Pat, second time I've read your injector testing procedure. Will attempt as soon as it gets above freezing in Pa. Question: Does it matter if the testing is done w/ warm or cold engine??

[MotoSook]

Pat, when I tested mine, they were not balanced either...but close enough. Spray pattern were great and car ran great. Any chance you might have calculated flow rate?

I'm trying to collect a sampling of flow rate so anyone out there have data, please post it.

[Pat S]

Shouldn't matter cold or hot, you'll have different pressures total and flow amounts, but the injectors should be flowing even under both scenarios.

Souk,
I didn't do any flow calculations. Not sure if you could actually do that and get meaningful data while the injectors are on the car. A lot of factors would change the results such as mixture, pressures, temp, etc...

[MotoSook]

Pat, I tested mine cold for max flow rate with the plunger all the way up and it gave me a value close to the theorectical value...I felt it was a good shadetree test...

Good job on the R&R..everyone should R&R their CIS if they have not done it.