Stupid question, but I had someone tell me something to the contrary. On a 97 C230 w202, with the key in the run position but the car not running, I should be able to hear or even feel the fuel pump running if I am about 6 inchs away from it right? having some starting issues.

With FI cars in general, a fuel pump will run for 2 to 3 seconds when the key is in the on position but engine not running. I don't recall if these cars do this or not. ( I have a 97 SL320 / C280 and E320, all have the same engine family / computer system. )

A sure way to test is place a test light on the fuel pump wires and turn the key on.

The fuel pump relay should be in the right front corner trunk just ahead of the spare tire. It has a fuse on top, I "think" the relay is green.

Choover, if the fuel pump wasn't working the engine would not start and keep running. A dirty fuel filter could be restricting fuel flow. What is the mileage on your 1997 C230? I suspect a problem with the ignition system. When were the spark plugs and ignition wires last replaced?

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Fred Hoelzle

Car tries to run with starting fluid so I am getting spark. I jumped the relay and could hear the pump. So far I have:
replaced the crankshaft position sensor
replaced the fuel pressure regulator
replaced the fuel filter
replaced the pump
replaced the K40 relay in the engine bay
replaced the fuel pump relay
replaced the injectors and fuel rail
Still nothing. I have no fuel coming out of the injectors, but pressure in the fuel rail. I did notice the vacuum line from the fuel pump regulator was just hanging under the intake manifold. Before I could hook that up the tow truck showed up to take it to the shop. Frustrated and giving up.

The 97 uses a DAS X anti theft chip in the key. If the DAS box ( 3 x 5 x 1 inch black box behind the speedo ) does not send the proper signal to the engine computer, the injectors won't operate.

If you do swap engine computers, you must use the matching DAS box and key otherwise the car won't run ( or will just start / stall )

The disconnected fuel pressure vac line has no affect on starting since manifold vacuum is near zero when cranking anyway. The hose reduces fuel pressure when intake manifold is high. This is done to keep a constant pressure drop across the injectors.

According to the professionals( it was the fuel pump. That means I replaced my bad fuel pump with a defective pump and that sent me down a long and winding road.

In post 4 you state you have pressure at the fuel rail but nothing from the injectors. pressure at the rail = fuel pump working.

That was my opinion too, but apparently it just was not enough. They replaced the fuel pump only and it started right up. I am just as confused as anyone.

Did you check fuel pressure with a gauge or just by pushing the valve? A gauge is more accurate than a valve press.