1968 Shelby GT500

Fuel Injector Cleaning

By Dusty Sharp
My fuel injection system sat around for about 4 years before I finally got around to installing and cranking it up. Needless to say, the injectors were gummed up something fierce! Here’s what I did to get mine clean.

 
 
 
 
 
 
 
 
 

You will need a Fuel Injector Service Kit:
• 16 O-Rings
• 8 Spacers
• 8 Pintle Caps
• 8 Filters

Remove the o-rings and pintle caps. Then use the #10 machine screw to remove the internal filter from the injectors. Shown below I’m using a special tool, but you can use Vise-Grips.
thread screw into old filter

wiggle and pull out filter

Next, get some fuel injector cleaner from the parts store. I like the Chemtool brand stuff in the white can with red and blue label. You’re supposed to dilute this stuff in a tank of gas but for this purpose I used it full strength. Put the injectors in a bucket and pour in the cleaner until it covers them. Let the injectors soak over night outside. Keep this away from animals and childred!

The next morning the fluid will be full of gunk and slime from inside your injectors. As you take each injector out of the cleaner, place it into the test wire harness, place a compressed air nozzle at the spray end (backwards) and throw the switch while you give it a blast of air. Point it away from you because more gunk and slime will spew out. If you don’t have compressed air, you can blow into the end of the injector, but use short piece of clean fuel or vacuum hose between your lips and the injector to avoid getting any of that nasty cleaner in your mouth. Repeat this procedure with each injector, rinse once more in clean cleaner, then dry them off and reinstall the o-rings.

First, put together a simple injector test circuit with some alligator clips, wire, a momentary toggle switch, and a spare injector harness plug (you can buy one new for a couple dollars or from a junkyard harness). Put each injector in the makeshift harness and check it with the switch. You’ll here it click when you throw the switch unless its gummed up too bad. Even if they do click, they could probably still use a cleaning. Next, get a bottle of professional injector cleaner from the parts store meant for the cleaning machines. Remove all the O-rings from the injectors are place them in a bucket. Pour the cleaner in until they are all covered and let them soak over night. The next morning the fluid will be full of gunk and slime from inside your injectors. As you take each injector out of the cleaner, place it into the test wire harness, place a compressed air nozzle at the spray end (backwards) and throw the switch while you give it a blast of air. Point it away from you because more gunk and slime will spew out. Do this with each one, rinse once more in clean cleaner, then dry off and reinstall the o-rings.

After I did this my motor ran great and has ever since. Hope this helps.

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