DYI Injector Cleaning and Flow Testing

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RustyRatRod,
Nothing is ever easy for me :). I cannot get away from electronics and working with my hands. I have to measure and make sure they are working like a charm.
 
Dave, hard at work LOL

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Data acquisition and analysis is accomplished in this clean, cool computer facility
 

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Thats looks too organized for me. I enjoy entropy. I am also a pack rat. I have clean up plan similar to Uncle Buck's quit smokIng plan.

Wow nice looking computer chick. That photo dates to about mid 70's, I see the card reader, and huge disk drives.
 
I got some parts today. I ordered from MPJA.com. They supply reasonably cost parts and equipment. Some stuff from China. They have Sunpro mechanical oil pressure gauges for $5. The aluminum bud box for $11, Roll of 100' x 5/16" heat shrink for $11. They also had some gas springs for $4. They liquidate, so if you see something you want, order soon.
 

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I ordered a whole selection of 4 ft? lengths of shrink from mouser, and had it all together at one end with rubber band. Was doing some work last year on my old Ranger and figured out later that I left it "placed" in the gap between shell and cab, then drove off.

How far "small" will that 5/16 shrink?
 
Heat shrink, shrinks typically 1/2 diameter. It is actually 9mm and shrinks to 4.5mm. They have a huge number of sizes and colors. Price varies by diameter. It is good stuff, has agency approvals. I plan to use this to bundle some of the efi wiring to injectors. I have a few other rolls in smaller diameter, a lifetime supply.
 
I cut holes in the box lid for LCD and keypad. I need to cut holes in box for connectors, then wire it up. Weather is not so good tomorrow, but good for doing electronics.
 

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You're a lot more "professional" at this 'n I am. Some of my "homebrew" stuff is truly ugly LOL
 
Most of the stuff I build has to last for years. I often have the client do the box details if they have the tools and manpower. I work too slow, as a machinist. I do things no machinist may do. This morning I cut down some threaded standoffs, and the heads off screws, so the display could mount. I also cut plexi-glass, and filed the corners to fit the opening. I could have saved time if I had an assortment of small metric screws.

I often change the display for one with LED back light, and 2 x 24 characters. The back light makes the display much easier to see. They can be white with black, or black with white, for $20, NewHaven from digi-key.

I wanted to do some work with graphics displays, my AVR C compiler has libraries for those. The price and ease of use of tablets as GUI, has stopped me from that. It is amazing how changes in technology changes my plans. It would still be a way to go if there was a large volume, but for one unit, no way.

As a side note:
There are ways to add RS232 and bluetooth to tablets, so they could be used on Holley or other engine management units. By using a protocol analyzer and monitoring communications using a PC, the protocol could be learned. From that, code can be written using B4A compiler, for android, to replace the PC. It would take time, but it is all possible. The Saleae logic I mentioned a few posts back, is a fairly good protocol analyzer. It will record the full duplex serial communication strings. Just by pushing command buttons, or other GUI features. You could find out what is in the commands, and reproduce the functionality. While all this may seem complex, it is not.
 
I got carried away in my last post. I want to share how the keypad works. The keys have arrows. They are used to navigate menus. In the display picture, while difficult to see, in the upper left is 1T. There is a cursor under the 1, pressing up arrow changes to test 2. When test 2 is selected, the test parameters are shown. Pressing the right arrow, moves the cursor to S, for start. Then if the up arrow is pressed the unit will start, and counts count down. It can be stopped if the left arrow is pressed, and reset counts if pressed again.

Using the right arrow to select M, is for modifying test parameters. The keys are used to select parameters and change values. Exiting with the left arrow saves settings.

My engine management sytems use similar commands via serial communications or bluetooth. It works well in a car, just a few keys to select value, and change. A convenient way to make changes in a car. Using numeric entry, or mouse in a car would be ridiculous. Working at a desk, is much different than in a moving car. I also have the help of a driver, I do not drive and tune, unless on my property.
 
I found a couple hours today to complete the injector flow bench. My work was done a couple hours at a time. I have about 16 hours total, and about $100 in parts.

It is possible to remove five 1/4" bolts to change the system over to the 1st generation Bosch hose barb injectors.

High and Low impedance drives are selected by switching location of one cable end.

The graduated cylinders are 50mL.
 

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Thanks Del,

I skipped a few steps like paint and the electronic pressure regulation. I have the parts, but need to get started testing injectors to complete my kitcar project.

I will post again, possibly with a video of it operating, and some test results on Monday. Some depends on weather. I plan to do first tests on driveway, in case of leaks or fire :).
 
Here is a video. Injector #1 is flowing slightly less than others. It is getting better. It shows up more at the low 1.25mS pulse width.

[ame="http://youtu.be/t_EEZX8RGMg"]http://youtu.be/t_EEZX8RGMg[/ame]
 
I have only tested two sets. In the first set only one injector would click. So I used brake cleaner as a solvent is a short tubing loop from injector feed to delivery to loosen up the varnish. I was able to get them all clicking.

Most injectors take about 1mS to open fully. I started 5 mS and 900 RPM. The injector that was not initially stuck flowed clear gas, the rest passed significant contaminants. The #1 on the bench was the worst, the varnish changed the fuel color to orange. Flows were not even to start with, and became acceptable after a few runs.

The second set of injectors were about 40 years old, I have no idea how long they were in use. They were all stuck to start with from drying out with full fuel system. When I first tested then there was a huge amount of garbage. One injector would stick open, and would dribble fuel without being energized. It would flow more fuel than the rest, it showed up more for low pulse widths. Another injector flowed less, likely a restriction or slow to open. It would flow less at low pulse widths. The more I tested, the cleaner the discharge, the flows became close. I did not expect the initial junk, much more and larger in size than I expected. The first run or two gas was burned safely in an open large tuna can. The later clear flows were filtered and added to the lawn mower.

There is likely some uncertainty in the measurements. I am happy with a match of 1mL or less difference. I record levels, and retest ... I have added some sea-foam to the gas and may test again today.
 
One big question for me is "what is safe" for cleaners. Stuff like brakecleen will not touch some varnish and gum, but other cleaners tear up plastics and rubber products
 
That is a good question, and why I start with junk. The brake clean immediately strips the paint off the injector body, I do not like that.

The sonic cleaner cleaned the outsides nicely, but did little on the inside. I can only use water based cleaners, so not much future there. Gas seems to work well once the pintel is free to move via solenoid action. I doped the gas with 5% sea foam, ran the injector a bit, then let it sit overnight. I did a 3 runs and all was good, just a bit more crud on first run. I do not believe in additives in my cars, really do not know what I am missing. I like you think it is hard on hoses.
 
KitCarlson said:
I found a couple hours today to complete the injector flow bench. My work was done a couple hours at a time. I have about 16 hours total, and about $100 in parts.

It is possible to remove five 1/4" bolts to change the system over to the 1st generation Bosch hose barb injectors.

High and Low impedance drives are selected by switching location of one cable end.

The graduated cylinders are 50mL.
Click to expand...


AWESOME work!!!!!!!!!!!!!!!!!! and great thread!!!!!
 
Del,

I dissected an injector that had a body leak. It looks like someone used a screw driver against the plastic upper in an attempt to remove a hose without cutting hose crimp. I figured there was no way to fix. I used a hacksaw to cut around the center of body.

I exposed the coil, pintle, and return spring. The spring appears to be stainless steel. The coil is exposed to the fuel. The pintle/slug is captive in the lower section. The greatest concern is cleaners removing enamel insulation on the coil. I damaged the coil with saw, but I should still be able to test the insulation tolerance to chemicals.

The inner section was filled with coffee grounds on a micro scale, same color and texture. I am not a coffee drinker, I am much too hyper already. I have cleaned a coffee pot or two. The amount of volume in the section, and the volume of crud, puts into perspective the amount that passed when I first flowed the old injectors.
 

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WOW I had no idea the solenoid insulation would be directly exposed to fuel. I would think this would certainly limit some chemicals.
 
Great work, thanks for posting. Amazing they flowed as uniformly as they did with all that crud inside. Most injector test rigs I have seen use much bigger cylinders, and they fill up very fast. I expect they are using a high duty cycle. Seems better to test the balance at low duty cycle like yours, since that is where the engine runs most of the time and where mileage matters most.
 
I suspect later injectors might have the coil injection molded over with plastic. I will dissect a more modern one if I find a bad one.

Bill,
They do flow much more fuel, for the test I am running at idle speed. I have cranked them up. For safety reasons I am limiting flow by lower repetition rate, of idle RPM. It is also easier to detect skipping, I can hear fuel pump change tone. I am using an old pump. When the injectors cleaned up the the pump runs smooth.

I put off the pump control for now. I need to get a set of good injectors in my newly rebuilt engine. Car shows will be here soon.

I have plans to build a stand alone pump controller that has more integrated features than ones available on the market. I find the ones on the market run about $400, and lack necessary features to correctly do carb, EFI, turbo in one package. There is likely a huge safety liability involved, so I will never sell them.

RustyRatRod,
Thank you for the kind words.
 
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