Snowballs

A interesting tale of cause and effect:

I've been fighting with this Pontiac for a long time. I couldn't seem to catch a break. Stuff just didn't work right.

To catch everybody up, I've had massive fueling problems for awhile. Just way too rich. Gas mileage, which was near 15 mpg right after I put the Megasquirt on, had fallen to 10-12.

I'd found a torn diaphram inside my fuel pressure regulator. The tear was allowing fuel into the intake via the vacuum line on the regulator. Fixed that. Still too rich, even with the FPR backed all the way out.

I dyno'd the car, and got a stellar 109 hp. Not right. I took the car to an exhaust shop and had them look at the catalytic convertor. It was fine, but there was lost of unburned fuel in the exhaust tract.

I finally got a decent fuel pressure gauge, and pressure was pegged at 60psi at idle. Way too much. Then, to top everything off, it started leaking from a fitting at the fuel filter. I parked it. Tests with the new gauge revealed I had a restriction INSIDE the fuel rail.

So, today I pulled the rail off, filled it with carb cleaner, and blasted it out with compressed air. I put it back on. I then pulled the line that runs from the fuel filter to the fuel rail out of the car and re-did the AN fitting on the end. I put it back on. I hit the fuel pump relay with 12v to fire the pump and watched the gauge.

46psi. I'd done it. I took the car out for a test drive and when I got back, my heart sank. It was leaking from the filter still, plus a leak out of the schrader valve on the fuel rail.

I pulled the filter off, and found the problem as soon as I loosened the clamp. I was greeted with a fine spray of fuel from a crack in the filter. I replaced the filter and put it back on. I then pulled the schrader valve from the rail, slimed it with thread sealant, and put it back on.

Fixed. Finally. I hope.

So, to recap:

A small amount of dirt in the rail caused a restriction in the return line that forced pressure from the outlet of the pump to the rail to not drop below 60psi. Over time, that pressure tore the diaphram in the regulator, causing a massive fuel leak into the engine. Once I repaired the regulator, it burst the filter and compromised the seal on the schrader valve, causing leaks onto the ground and onto the top of the intake manifold. It's a miracle the thing hasn't caught fire yet.

A little dirt, months of frustration. Months. And wasted gas. 10mpg with $3.50 gas sucked. Now that it's $4, I'm glad it's fixed, and I hope it stays that way.