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Fuel Leak

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Cold Start O-Ring Replacement

by Denny Lambert

If you have a strong odor of gasoline coming from the engine bay of your V6 Fiero, especially noticeable for a while after shutting off the engine, check the cold-start assembly connection at the fuel rail. There is a small o-ring inside the connector assembly that tends to leak as the car gets older. Breakdown with age is the governing factor here, not mileage, so this failure will increase in frequency as these cars age. Once a leak starts, this becomes a very dangerous situation and must be fixed immediately.

Location of cold-start assembly at fuel rail.

Location of cold-start assembly at fuel rail.

The only replacement o-ring I have been able to find is in the cold-start o-ring kit available from GM dealers. This kit consists of three o-rings, and I've found it easier to replace all three while you're at it.

My recommendation is do not tell the parts person it's for a Fiero and you'll get better service. In fact, there is no need to mention any particular vehicle. Just tell them it's an o-ring kit and give them the part number: 17111954.

The first step is to be certain the pressure is out of the fuel system. There is a Schrader valve on the right side of the fuel rail. Hold a rag over the valve while relieving the pressure to prevent fuel from spraying into your eyes.

Next, remove the distributor cap to give yourself more working room. Ideally, removing the entire distributor would be better, but not absolutely necessary. You'll still be able to reach everything, it just takes a little patience to work the cold-start assembly out of the confined space in there.

You'll need the following tools: 18 and 16-mm open-end wrenches, 10mm socket, ratchet handle and an extension of at least 10 inches.

I recommend removing the 10mm bolt at the injector first. The injector is located in front of the distributor (firewall-side of engine), and low on the intake manifold. The electrical connector on the injector releases by depressing the wire toward the injector. Push in and hold, then pull on the connector. Loosen and remove the 10-mm bolt.

Cold-start assembly

Now you can loosen the fitting at the fuel rail using the 18-mm open-end wrench. This is a two piece pressure fitting, but will unscrew as one piece and come out with the assembly.

As I indicated, patience is now required to maneuver the assembly out of there. To replace the small o-ring (the leaker), you must disassemble the two-piece fuel rail connector. Since the fitting is very tight, I recommend locking it in a vice (be very careful and do not over-tighten the vice or you'll crush the fitting!) and using the 16 mm wrench to loosen the inner part of the fitting. You may need to tap on the wrench with a hammer to break the fitting loose.

Once the fitting is separated pull the piece with threads on both ends off the cold-start tube.

The medium-sized o-ring in the kit replaces the combination washer and seal. Remove the small o-ring using a small screwdriver or small needle-nose pliers.

After replacing the two o-rings, push the fitting back on the cold-start tube and tighten the fitting.

The large o-ring in the kit replaces the large one on the cold-start injector.

Inner fitting removed from tube.

Cold-start injector

Reinstall on the engine by first inserting the fitting at the fuel rail, but do not thread into place yet. Push the cold-start injector into its opening, then replace the 10-mm bolt, but do not tighten. Now go back and thread the fuel-rail fitting into place, and tighten. Now you can tighten the 10-mm bolt at the injector.

Finally, replace the distributor cap, or distributor if you removed it. Fire up the engine. No more leak!