560sec fuel pump troubles
07-26-2006, 06:04 PM
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560sec fuel pump troubles
Hi guys, I am in a little bit of a delimma. I have been working on cars for a while now but this is my first real run in with a MB.
Anyways, I am doing a favor for a very good friend of mine. They were given a 1988 560SEC with 60k original miles that was in near mint condition when it was parked by a sick uncle in 2003. All maintenance was current and it was in perfect running condition.
Fast forward to today, everything seems fine EXCEPT: it has no fuel pressure at all. I have drained the tank dry, refilled with 5 gallons of new premium fuel, and the fuel pumps do not get any power. I have replaced the fuel pump relay.
I'm not really sure what electrical part that could fail from sitting that would cause them to not get power except that I have added 5 gallons of fuel to the tank and the gauge has not moved any and the low fuel light is on. Could a low fuel condition cause it to cut power to the pumps? Maybe the sender could be stuck? Like I said, I am not very familiar with the workings of Mercedes cars.
Any incite would be greatly appreciated. This seems to be a fine specimen of this model automobile and I would love nothing better than to help get it back on the road.
Anyways, I am doing a favor for a very good friend of mine. They were given a 1988 560SEC with 60k original miles that was in near mint condition when it was parked by a sick uncle in 2003. All maintenance was current and it was in perfect running condition.
Fast forward to today, everything seems fine EXCEPT: it has no fuel pressure at all. I have drained the tank dry, refilled with 5 gallons of new premium fuel, and the fuel pumps do not get any power. I have replaced the fuel pump relay.
I'm not really sure what electrical part that could fail from sitting that would cause them to not get power except that I have added 5 gallons of fuel to the tank and the gauge has not moved any and the low fuel light is on. Could a low fuel condition cause it to cut power to the pumps? Maybe the sender could be stuck? Like I said, I am not very familiar with the workings of Mercedes cars.
Any incite would be greatly appreciated. This seems to be a fine specimen of this model automobile and I would love nothing better than to help get it back on the road.
08-11-2006, 12:27 AM
#3
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Originally Posted by ZBoggs
Hi guys, I am in a little bit of a delimma. I have been working on cars for a while now but this is my first real run in with a MB.
Anyways, I am doing a favor for a very good friend of mine. They were given a 1988 560SEC with 60k original miles that was in near mint condition when it was parked by a sick uncle in 2003. All maintenance was current and it was in perfect running condition.
Fast forward to today, everything seems fine EXCEPT: it has no fuel pressure at all. I have drained the tank dry, refilled with 5 gallons of new premium fuel, and the fuel pumps do not get any power. I have replaced the fuel pump relay.
I'm not really sure what electrical part that could fail from sitting that would cause them to not get power except that I have added 5 gallons of fuel to the tank and the gauge has not moved any and the low fuel light is on. Could a low fuel condition cause it to cut power to the pumps? Maybe the sender could be stuck? Like I said, I am not very familiar with the workings of Mercedes cars.
Any incite would be greatly appreciated. This seems to be a fine specimen of this model automobile and I would love nothing better than to help get it back on the road.
Anyways, I am doing a favor for a very good friend of mine. They were given a 1988 560SEC with 60k original miles that was in near mint condition when it was parked by a sick uncle in 2003. All maintenance was current and it was in perfect running condition.
Fast forward to today, everything seems fine EXCEPT: it has no fuel pressure at all. I have drained the tank dry, refilled with 5 gallons of new premium fuel, and the fuel pumps do not get any power. I have replaced the fuel pump relay.
I'm not really sure what electrical part that could fail from sitting that would cause them to not get power except that I have added 5 gallons of fuel to the tank and the gauge has not moved any and the low fuel light is on. Could a low fuel condition cause it to cut power to the pumps? Maybe the sender could be stuck? Like I said, I am not very familiar with the workings of Mercedes cars.
Any incite would be greatly appreciated. This seems to be a fine specimen of this model automobile and I would love nothing better than to help get it back on the road.
08-18-2006, 07:24 PM
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Thanks for all your help guys! I replaced both pumps, and it turned out that there was a short in the battery. Somehow it would turn the motor over but not power the accessories. I dunno. 
It does run and drive now. The idle is a little funny, but after sitting for three years I figured I would change all the fluids and just drive it for a while and see what happens.
The only real problem remaining is that there are no turn signals, brake, or backup lights. The hazard lights work great and all of the fuses checked out with a multimeter. I know there is some sort of relay in the fuse box but is there any test I can do with it?
Thanks again guys!
It does run and drive now. The idle is a little funny, but after sitting for three years I figured I would change all the fluids and just drive it for a while and see what happens.
The only real problem remaining is that there are no turn signals, brake, or backup lights. The hazard lights work great and all of the fuses checked out with a multimeter. I know there is some sort of relay in the fuse box but is there any test I can do with it?
Thanks again guys!
