SL/R107: 560SL fuel problem
02-07-2006, 02:18 PM
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560SL fuel problem
1986 500sl - 88000 mi. serviced regularly. have had it stall (dead) on two occasions under normal conditions then restart after a few tries. acts like it's fuel starved. assuming no filter issues what's the probability of a bad pump relay? how do i check it out? thanks in advance.
02-08-2006, 01:55 PM
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1988 560SL
Originally Posted by frankjones
1986 500sl - 88000 mi. serviced regularly. have had it stall (dead) on two occasions under normal conditions then restart after a few tries. acts like it's fuel starved. assuming no filter issues what's the probability of a bad pump relay? how do i check it out? thanks in advance.
1. Fuel Filter
2. If evidence sugests it, the fuel pick-up/dirty tank
3. Fuel Pump Relay
4. Fuel Pump
5. OVP, but not if you do not have any high-idle problems
Problems like this have been documented where the relay caused all the problems, but just as easily could be rusty/dirty tank. One outside cause could be the sump in the fuel tank. There is a sump-like fixture that is in place to prevent fuel starving during cornering (think coffer dam). It acts as a buffer, kinda like the fuel accumulator (which I do not suspect here, unless you have routine starting problems first of the day). If the sump is rotted out, the take-up can be starved when the tank is less than a 1/2 to 1/3 full. Incidently, the "sump" is fed by both the fuel in the tank, but is directly fed by the return fuel line. It acts as an artificial, higher fuel level.
Hope this helps.
02-08-2006, 05:19 PM
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Originally Posted by Ears
I would investigate the following, and in order:
1. Fuel Filter
2. If evidence sugests it, the fuel pick-up/dirty tank
3. Fuel Pump Relay
4. Fuel Pump
5. OVP, but not if you do not have any high-idle problems
Problems like this have been documented where the relay caused all the problems, but just as easily could be rusty/dirty tank. One outside cause could be the sump in the fuel tank. There is a sump-like fixture that is in place to prevent fuel starving during cornering (think coffer dam). It acts as a buffer, kinda like the fuel accumulator (which I do not suspect here, unless you have routine starting problems first of the day). If the sump is rotted out, the take-up can be starved when the tank is less than a 1/2 to 1/3 full. Incidently, the "sump" is fed by both the fuel in the tank, but is directly fed by the return fuel line. It acts as an artificial, higher fuel level.
Hope this helps.
1. Fuel Filter
2. If evidence sugests it, the fuel pick-up/dirty tank
3. Fuel Pump Relay
4. Fuel Pump
5. OVP, but not if you do not have any high-idle problems
Problems like this have been documented where the relay caused all the problems, but just as easily could be rusty/dirty tank. One outside cause could be the sump in the fuel tank. There is a sump-like fixture that is in place to prevent fuel starving during cornering (think coffer dam). It acts as a buffer, kinda like the fuel accumulator (which I do not suspect here, unless you have routine starting problems first of the day). If the sump is rotted out, the take-up can be starved when the tank is less than a 1/2 to 1/3 full. Incidently, the "sump" is fed by both the fuel in the tank, but is directly fed by the return fuel line. It acts as an artificial, higher fuel level.
Hope this helps.
frank
02-14-2006, 12:19 PM
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1989 560SL
Same thing?
I've had a very similar problem with my 1989 (60K miles). It always stalls (feeling fuel starved) after driving for 1-3 minutes, restarts with no problem and will then run great for as long as I continue to drive it. Doesn't matter how full tank is or engine temp (will do it again if shut down even for a few minutes). Car has been tuned very recently, fuel filter is OK. Just before I put it in storage for the winter the check engine light went on, I was planning on changing the O2 sensor in April when I take it out again.
Let me know how your issue works out, maybe I have the same one!
Let me know how your issue works out, maybe I have the same one!
No hump from my pump.
