First determine what injectors you have and contact Mr. Injector, this is the best place to find all the o-rings and filters you'll need for your injector rebuild. He can also clean/rebuild your injectors for you.
Using the above list of parts and what ever else you might have to substitute, assemble a test stand as pictured :).
NOTE: I could have used a mega-squirt or some other system to build an injector driver for testing. However, I didn't have laying around so I subsituted it for a Injector Pulse Generator and a BBQ Rotisserie for continous activation of the button on the tester. CAUTION! Fuel in an open area is not a good idea, USE A LOW-FLAMABLE Parts cleaner to operate your injector flow bench. ALSO, Read and follow all manufacturer precautions and recommendations.
Follow these simple steps and rebuild them yourself:
The injectors were each visual inspected and then the following injector cleaning process was completed.
1) Clean exterior of injector
Use a soft brush and parts cleaner to remove all exterior debris on the injector. Caution! Never touch any part of the exposed tip on the injector with any sort of physical cleaning device, will use the Ultra Sonic bath to clean this end.
2) Test Injector Coil Resistance
You’ll need to know the specifications for your fuel injector. Check the ohms from one tip of the electronic plug to the other and record readings. Google injector specifications for your specific injectors, one good place is:
3) Test Injector Flow Pattern
Visually inspect the flow pattern of the injector during operation.
4) Test For Injector Leakage
Visually look at the end of the injector while pressurized and look for leakage.
5) Test Injector Flow/Volume
Using a measuring device measure the amount of fuel delivered during a set amount of cycles. We used a rain gauge for lack of access to a graduated cylinder. It was accurate enough to perform the test and do a comparative analysis of the set of injectors as a whole.
6) Remove Injector screens and o-rings
TIP: The fuel injectors have a small screen with a brass collar around the inside of the top input port. This brass collar is the key to removal. You’ll need to find a course threaded screw just slightly too big and thread into the brass collar. Holding the screw in a vise use a lever, like a screw driver, against the edge of the input port and pry the screen/filter out.
7) Clean Injector Tips in Ultra Sonic Bath
Rig some type of holding device to submerge the tips of the injectors into an ultra sonic bath for a period of an hour or so. Then rinse the injectors for about a third that time.
NOTE: It’s important in most of the little jewelry cleaners you get that you do not lay the injector in the cleaner. The basket isn’t capable of holding the weight and it impedes the cleaning vibrations. We used some cut PVC elbows clamped to a bolt to suspend the tips into the cleaning liquid.
8) Back flush the injectors
This is an important step to make sure any debris dislodged are flushed out of the injector interior prior to installing a new screen. We rigged a pressure port off the side of the rail to blow back through the injector while activating it.
9) Coat inside with oil
Spray inside of injector with a little wd-40 or some other light oil and let run back out. Just prolongs shelf life especially if you’re not going to be using them immediately.
10) Install new filters
Lightly tap the new filter into the injector. It’s best to hold it in your hand and use a small plastic device to tap in.
11) Install new o-rings
Grease them with synthetic grease and slip over injectors.
FINISHED! That’s it; your injectors should be read for service.
Contact Watkinsmotorsports for more info: Email Me for Injector Rebuilding Details
Mike Rowand, Contributions to DIY Fuel injector cleaning.
Mike Rowand, provides lots of good how to information on fuel injection cleaning and systems in general.
OTC Fuel Injector Pulse Generator
OTC's website, they manufacture the pulse generator I used, follow the link above to visit their site.
Pulse Generator Circuits
A good site to find pulse signal generator wiring diagrams and other related information.
Professional Fuel Injector Rebuild
Want to see how a professional shop does it? Visit Cruzin Performance, they have a great step-by-step fuel injector rebuild with photos. Som of the insperation for my fuel injector flow bench from some of the information found here.
The fuel injectors being used in this mustang are: Delphi / Lucas 36 lb / hr. Disc Injectors Part Number Delphi D3165BA (Lucas old 5203002, Lucas New 621037)
Do you need to know how big of injector to use? Read: How to Pick the correct size fuel injectors
These injectors, like half the other parts used to build this mustang, were bought in a package eBay deal. The age and usage on them was unknown at the time of receipt.
After using them for a year or so, we decided they may need to be checked and flow tested. Not having a machine shop on hand or a garage for that matter, we decided to build our own flow bench to see what we could find out about improving the performance of a fuel injector.
We scavenged a fuel injector rail from a 5.0 litter mustang and used a new Summit Racing Fuel pump to feed the system. From there it gets MacGyver, so all the engineers out there with a load of money and equipment please leave now; you might not appreciate the choice of materials used to build this device. Nonetheless, the homemade fuel injector flow bench we created had a very simple material list from stuff we had available. It proved functional and we documented positive results on cleaning several sets of injectors.