How to replace fuel injector basket micro filters

How many filters you need

You need one basket filter per injector:

A spare or two helps in case one gets dropped or seats crooked.

Before you start: safety

• Work in a well-ventilated area, away from any open flame, spark or pilot light. Don't smoke. Keep a fire extinguisher rated for fuel fires within reach.
• Relieve fuel system pressure before opening any fuel line. A common way is to pull the fuel pump fuse or relay, start the engine and let it stall, then crank it for a few seconds. Follow the service procedure for your vehicle.
• Disconnect the negative battery terminal.
• Wear safety glasses and nitrile gloves. Expect a little fuel to spill when the rail comes off, so keep rags handy.
• Plug or cover open fuel ports and intake holes so dirt can't get in.

Step-by-step

1. Remove the fuel rail and injectors

   Unplug the injector connectors, then unbolt the fuel rail. Lift the rail and injectors out together, then unclip each injector from the rail. Keep the injectors in cylinder order if you want them to go back in the same positions.

2. Remove the old O-rings and pintle cap

   Cut or roll off the upper and lower O-rings. If the injector has a plastic pintle cap on the spray tip, pry it off gently with a small plastic pick, taking care not to touch the spray tip. Throw away all the old seals. Don't reuse them.

3. Pull out the old basket filter

   The basket filter sits inside the top (inlet) end of the injector.

   • Thread the basket filter removal tool into the old filter, then twist until it grips.
   • Pull the filter straight out, keeping the tool in line with the injector.
   • Don't push the filter deeper into the injector body, and don't dig at it with a drill, screw or pick. Debris pushed inside, or a scratched inlet bore, can ruin the injector.

   The old filter usually comes out damaged, so throw it away.

4. Clean the inlet and the injector body

   Wipe the outside of the injector clean. Hold the injector with the inlet facing down, then wipe the inlet bore or blow across it at low pressure so loose debris falls out instead of being pushed toward the valve. Look for cracks in the body or damaged connector clips. If an injector is cracked, replace it rather than rebuilding it.

5. Press in the new basket filter

   • Set the new filter squarely in the inlet, closed basket end first, the same way the old one sat.
   • Use a flat punch or a small socket a little smaller than the inlet bore, and press or tap the filter in gently until it sits flush with the top of the inlet.
   • Keep it straight. If it goes in crooked, pull it out with the tool and use a new one.

6. Fit a new pintle cap and new O-rings

   • Press a new pintle cap onto the spray tip if your injector uses one.
   • Fit any spacers or seal rings in the same positions as the originals.
   • Lubricate the new O-rings with a light coat of clean engine oil, then roll them into their grooves without twisting them. Measure each new O-ring against the old one, or against the original part's size, before fitting it.

7. Reinstall the injectors and rail

   Clip the injectors back into the rail, then press the assembly into the intake ports evenly. Don't force it. If an O-ring is pinched, take it out and check it. Bolt the rail down, plug in the connectors, and reconnect the battery.

8. Check for leaks

   Re-install the fuel pump fuse or relay. Turn the key to "on" (without starting) two or three times to build pressure, and check every injector and fitting for wetness or a fuel smell. If you see any leak, switch off and fix it before starting the engine. Then start the engine and check again at idle.

FAQ

Do I have to take the injectors out to change the filters?

Yes. The basket filter sits in the injector's inlet, which is covered by the fuel rail. The injector has to come off the rail to reach it.

What size are the filters?

EV1, EV6 and EV14 style top-feed injectors commonly use a micro basket filter about 6 mm in outside diameter and about 13.8 mm long. Compare a new filter with your old one before you fit it.

Can I reuse the old filter?

It's not recommended. Removing a pressed-in filter usually distorts it, and new ones cost little.

Do I need new O-rings too?

Yes. Old O-rings harden and flatten with heat and age, and they're the seal that keeps fuel in and air out. Replace them every time an injector comes out.

Which O-ring material should I use?

FKM (fluoroelastomer) O-rings are a common choice for gasoline. Check that the seals you buy are rated for the fuel you run. Some are rated for gasoline and E10 only, not E85 or flex fuel.

Will new filters fix my engine problem?

New filters and seals are routine maintenance, not a diagnosis. If you're chasing a running problem, have the injectors flow-tested and check the rest of the fuel and ignition system as well.

Can a basket filter be pushed out from the bottom?

No. Pushing it through the injector can damage the internal valve. Always pull it out from the inlet end.

What you need

• Basket filter removal tool and micro filters. The micro filter removal tool is made in the USA. It's sold alone or with packs of micro basket filters.
• Rebuild kit for several engines or a shop. The Universal EV1 Rebuild Kit, 200-Injector Service Tray + Removal Tool has enough micro filters for 200 injectors, plus O-rings, seal rings, spacers and pintle caps, and comes with 1 removal tool in the box.
• Flat punch or small socket, a plastic pick, clean engine oil, rags, safety glasses and gloves.