wlacey

Hey,

I've used this board before for ideas. My C280 (136K) ran poorly after a 40 mile freeway run. I stopped at an intersection, the light changed and I tried to pull through but the car lurched and bucked. I got through the intersection, pulled off to the side, stopped the car and restarted and the car just cranked and cranked. It caught briefly but ran very poorly never getting to a steady idle. Car was towed home, hasn't started since - cranks but no combustion.

Based on info on this forum, I swapped out the Crankshaft Position Sensor thinking the car behaves as if it is getting no gas. Alas, after putting in the new CPS, same problem. I began thinking fuel. The Bentley Manual I've been using suggested removing the fuel pump relay and jumpering it to test for fuel pump operation. This I did and no fuel pump noise - I was surprised. The manual next suggested, removing the connector to the fuel pump, putting a volt meter in the leads to the fuel pump and then putting the jumper in again. This I did and I promptly read 12 volts - sort of proving I am getting proper power to the fuel pump.

My question: to a more experienced mind, does this sound like a bad fuel pump ?

Is swapping out the fuel pump an fairly straight forward job?

Anybody here changed their own fuel pump?

Love the car, ran great for all the time I've had it - I cant' believe it is a serious problem.

Thanks for any help.
W

503C43 ////AMG

I have never changed the fuel pump but if you didn't hear it kick on then you might be correct in assuming it needs to be changed.

I found this thread that describes similar issues: http://www.benzworld.org/forums/w202...-followed.html

Jovsky

This might sound stupid, did you check the gas? Maybe you've run out of gas?

This happened to my friend who owns a C280. His car won't start and tells me his fuel gauge is still 1/2 tank full. We brought the car to the shop to have it checked and lo, the tank was empty. The gauge got stuck in one-half. Filled the car with gas and started right away. He had the fuel gauge repaired.

Just another option to look at.

wlacey

Not a stupid response at all Jovsky. Will eliminate the obvious before tearing into the job.

Thanks

503C43 ////AMG

I have read in other threads that the lack of fuel was the culprit as well. The OP had stated he knew he had enough fuel but the tow truck driver added a couple of liters and then "rocked" the car back and forth and the car started. Either way you need air, fuel, and spark so start with one and move on to the next once you have eliminated each variable.

503C43 ////AMG

Any updates on a diagnosis?

wlacey

Problem solved. It was indeed the fuel pump.

Picked up a Pierburg for $238 and a new filter from NAPA and she is back on the road again. Actually running better, the car had a very responsive initial accelerator response so that it sort of jumped when starting from a dead stop. Now, that jump is gone, I guess the engine management system was compensating for low fuel pressuer and that is no longer necessary.

Thanks for everyone's help from the forum.

503C43 ////AMG

glad to hear you are back on the road