Saturday, June 14, 2008

Fuel Pumps, all models

For the final installment of the big 3 common failures I most often note on my clients cars, I will be talking about fuel pumps.

A Walbro brand fuel pump

The name of the thing is pretty self explanatory, no?

The pump is submerged within your gas tank and pumps fuel from the tank to the engine. If you listen very, very carefully while your car is running you can lightly hear it in most Saabs.

Saab OEM pumps are made by Bosch, and will usually last 100,000 miles or so. It is not part of any scheduled service, it is just one of those items whose day comes when it goes out.

Pumps often fail upon startup, they will simply not come on and the car will fail to start. Typically they will sputter and attempt to start a bit, but without sustained fuel pressure the system cannot manage to fire fuel through the injectors and ignition cannot occur.

The fuel pump lives inside a basket within the tank that contains the pump, a pre-filter, and also has the sending unit for the fuel level gauge built in.

The pump rests inside the basket

This particular pump is from my Stage 5 tuned 1994 9000 Aero. I have replaced the factory pump with a larger, higher flowing pump, a Walbro 255LPH. This pump is the most common for racing applications that require more fuel supply to the engine.

My Walbro 255LPH pump installed

Fuel pump replacement on a c900, 9000, or 9-5 takes about 1-1.5hrs. On a OG9-3, it takes about 3 hours because removal of the gas tank is required. The fuel pump inserts run about $180. Your dealer will attempt to replacement the entire basket assembly instead of the pump insert, and list price of the assembly is over $600. By replacing only the insert, it saves me time and you money, so we both come out on the plus side.

That's all for now

Take care,

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