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My 99 ml 430 with 156K has for the past month or so gone thru several fuel pump relays. They are quite warm to the touch. The big problem is that if I dont pull the relay at nite the vehicle wont start because the battery is drained.
Is this a ML issue for this model year and what is the solution.
Thanks for the quick help!!
FYI....before I changed the first relay there was a buzzing sound coming from the fuel pump area when the car was off. now with the second relay replaced and several weeks with no problem again the ML is dead for no apparent reason....went the relay and again it was melted slightly.
thx
E Box fan is in the "box" under the hood where all the relays are installed on the driver's side. Its there to cool all of the relays. Your problem could be this or perhaps the fuel pump is on its way out and is drawing too much current. However this is an issue that could leave you stranded in the wrong place at the wrong time. I would have it correctly diagnosed by a dealer who knows the vehicle well and has the equipment to correctly diagnose the problem. I say dealer because many independents do not have the equipment, knowledge or resources to correctly diagnose something like this.
when the first relay went bad....when I would shut the ML off I could hear a high pitch whine comming from the fuel tank area....
have there been other MLs with the issue and what is the solution. I need feed back ASAP so to take this to the dealership so my wife does not break down.
what is the extimated cost at $130./hr
thx
when the first relay went bad....when I would shut the ML off I could hear a high pitch whine comming from the fuel tank area....
have there been other MLs with the issue and what is the solution. I need feed back ASAP so to take this to the dealership so my wife does not break down.
what is the extimated cost at $130./hr
thx
The high pitch wind comming from the left rear tire area is probably the fuel pressure regulator located in the fuel filter. Ther regulator should only be in operation when the fuel pump is on. The fuel pump should not be on after you turn off the ML. Therefore it looks like your fuel pump is running all the time which would account for all the problems you list above. This could be caused by a sticking fuel pump realy but could be some other priblem causing the realy to stay on all the time. I wouldn't fool around with this. I hate to say this but I think I should recommend having a Mercedes dealer look into this.
Mike
Have not heard of this problem as so far as the relay is concerned with any ML's. I have never experienced this problem with either of my W163's or my W164. Can't be a common problem, Could have been caused by a previous or the current owner neglcting maint or having poor maint performed.
I am having the exact same issue with my 2000 Ml320..
My fuel pump relay heats up unusually and there is high pitched whining sound coming out from near the gas tank a few minutes after a cold start. The sound goes away though, as soon as the engine is stopped.
I am getting my ebox fan checked tomorrow, since I am losing some other relays too, but rather infrequently.
I think, my ebox fan has died and living in the Sacramento heat is probably only making it worse.
I am curious to know, what the issue was with your problem.
My ML has 117K miiles on it...
Originally Posted by w163carnut
My 99 ml 430 with 156K has for the past month or so gone thru several fuel pump relays. They are quite warm to the touch. The big problem is that if I dont pull the relay at nite the vehicle wont start because the battery is drained.
Is this a ML issue for this model year and what is the solution.
Thanks for the quick help!!
FYI....before I changed the first relay there was a buzzing sound coming from the fuel pump area when the car was off. now with the second relay replaced and several weeks with no problem again the ML is dead for no apparent reason....went the relay and again it was melted slightly.
thx
I have the same problem with my ML320. It was the worst car, besides 1989 Ford Taurus, that I ever owned. The ML320 has 125k. I had brake problems most of the time, they would lock-up and burn. Had that problem for about 10 years, aat least once a year.
Now it keeps burning the fual pump reley. No other relays melt but only the fuel pump relay till its is melted totally, and to a touch it will burn you. I took out the fuel pump and did the best job I could to clean it. The car starts normally, drives normally, untill the fuel pump becomes melted. This car was a poor enginnered car. Just read all the negative things people wrote about the American built ML Series. No German cars have such problems. I have a Toyota Tundra 2001 V* 200k miles, allI ever did was change oil, tires, and put gas in it. I willdo tune-up soon on it. To replace the poorly build ML320 for my wife, I bought her a 2010 BMW X3 with M-Sport add-ons. It was built in Germany. My som has a 1995 M3 with 60k, never a problem, and it is which is amazing car. My other son has Toyota Camery, no problems. My sons wife drives a 2001 Acura MDX with 150k miles, not a single problem ever.
So, before I sell the ML 320, I need to fix the fuel pump relay. Going to the dealer is not an option because the car is worth very little, I think Kelly Blue book quoted it for $2000, lol, It was garaged its whole lifetime,has no scratches, original paint is perfect, Interior is perfect, motor runs strong, the brakes got finally fixed, but not at the dealer, dhey didn't know what they where doing. All the dealer knows is to charge a lot for service. The car was never in an accident, and it is a Florida car, one owner. I rather keep the car then sell it for only $2000. It is after all in excellent condition, except for he relay problem. After all the fixes, it is a great car, definatelly worth more then $2000.
I am curious to find out what is making the fuel pump burn out, again, no other relays or fuses burn out, or rather melt, and get extreamlly hot like the one end only fuel pupm relay. There is noise also like other people have posted coming from where the pump is. The pump is pumping, I installed new fual filter, and clened the pump very well. It is a mistry. Thank you all for your inputs on this forum about this issue, and good luck with your ML,s. Wish you lock with this car.
I have the same problem with my ML320. It was the worst car, besides 1989 Ford Taurus, that I ever owned. The ML320 has 125k. I had brake problems most of the time, they would lock-up and burn. Had that problem for about 10 years, aat least once a year.
Now it keeps burning the fual pump reley. No other relays melt but only the fuel pump relay till its is melted totally, and to a touch it will burn you. I took out the fuel pump and did the best job I could to clean it. The car starts normally, drives normally, untill the fuel pump becomes melted. This car was a poor enginnered car. Just read all the negative things people wrote about the American built ML Series. No German cars have such problems. I have a Toyota Tundra 2001 V* 200k miles, allI ever did was change oil, tires, and put gas in it. I willdo tune-up soon on it. To replace the poorly build ML320 for my wife, I bought her a 2010 BMW X3 with M-Sport add-ons. It was built in Germany. My som has a 1995 M3 with 60k, never a problem, and it is which is amazing car. My other son has Toyota Camery, no problems. My sons wife drives a 2001 Acura MDX with 150k miles, not a single problem ever.
So, before I sell the ML 320, I need to fix the fuel pump relay. Going to the dealer is not an option because the car is worth very little, I think Kelly Blue book quoted it for $2000, lol, It was garaged its whole lifetime,has no scratches, original paint is perfect, Interior is perfect, motor runs strong, the brakes got finally fixed, but not at the dealer, dhey didn't know what they where doing. All the dealer knows is to charge a lot for service. The car was never in an accident, and it is a Florida car, one owner. I rather keep the car then sell it for only $2000. It is after all in excellent condition, except for he relay problem. After all the fixes, it is a great car, definatelly worth more then $2000.
I am curious to find out what is making the fuel pump burn out, again, no other relays or fuses burn out, or rather melt, and get extreamlly hot like the one end only fuel pupm relay. There is noise also like other people have posted coming from where the pump is. The pump is pumping, I installed new fual filter, and clened the pump very well. It is a mistry. Thank you all for your inputs on this forum about this issue, and good luck with your ML,s. Wish you lock with this car.
Cleaning your fuel pump is not the answer. Sounds to me like a too high current draw from the pump. Replace it. Way back there was a change in the pump are you certain you have the latest one. I can't believe you have gone into such a rant over a vehicle that is 14 years old and is not maintained by the people that are the most qualified to do so. I had a 98 and an 02 W163. Both were very reliable cars, yes including the 98! Think you are driving the wrong car for you!
Couldn't agree more...fuel pump needs to be replaced.
Originally Posted by sosh
Cleaning your fuel pump is not the answer. Sounds to me like a too high current draw from the pump. Replace it. Way back there was a change in the pump are you certain you have the latest one. I can't believe you have gone into such a rant over a vehicle that is 14 years old and is not maintained by the people that are the most qualified to do so. I had a 98 and an 02 W163. Both were very reliable cars, yes including the 98! Think you are driving the wrong car for you!
Fuel pump is due around 150k miles/10 years...one can't expect mechanically moving things to not reach end of life eventually. I bet, the fuel pump is drawing more current than it should. my fuel pump relay issues vanished after I replaced my fuel pump at 130k miles...along with the CPS.
One question that has puzzled me over these relay issues is, what comes first from the battery side - fuse or relay? Why do relays burn out but fuses stay intact? Shouldn't it be the other way around?
I have the same problem with my ML320. It was the worst car, besides 1989 Ford Taurus, that I ever owned. The ML320 has 125k. I had brake problems most of the time, they would lock-up and burn. Had that problem for about 10 years, aat least once a year.
Now it keeps burning the fual pump reley. No other relays melt but only the fuel pump relay till its is melted totally, and to a touch it will burn you. I took out the fuel pump and did the best job I could to clean it. The car starts normally, drives normally, untill the fuel pump becomes melted. This car was a poor enginnered car. Just read all the negative things people wrote about the American built ML Series. No German cars have such problems. I have a Toyota Tundra 2001 V* 200k miles, allI ever did was change oil, tires, and put gas in it. I willdo tune-up soon on it. To replace the poorly build ML320 for my wife, I bought her a 2010 BMW X3 with M-Sport add-ons. It was built in Germany. My som has a 1995 M3 with 60k, never a problem, and it is which is amazing car. My other son has Toyota Camery, no problems. My sons wife drives a 2001 Acura MDX with 150k miles, not a single problem ever.
So, before I sell the ML 320, I need to fix the fuel pump relay. Going to the dealer is not an option because the car is worth very little, I think Kelly Blue book quoted it for $2000, lol, It was garaged its whole lifetime,has no scratches, original paint is perfect, Interior is perfect, motor runs strong, the brakes got finally fixed, but not at the dealer, dhey didn't know what they where doing. All the dealer knows is to charge a lot for service. The car was never in an accident, and it is a Florida car, one owner. I rather keep the car then sell it for only $2000. It is after all in excellent condition, except for he relay problem. After all the fixes, it is a great car, definatelly worth more then $2000.
I am curious to find out what is making the fuel pump burn out, again, no other relays or fuses burn out, or rather melt, and get extreamlly hot like the one end only fuel pupm relay. There is noise also like other people have posted coming from where the pump is. The pump is pumping, I installed new fual filter, and clened the pump very well. It is a mistry. Thank you all for your inputs on this forum about this issue, and good luck with your ML,s. Wish you lock with this car.
I bought a new fuel pump, installed it just recently, October 2012, and same problem persists. The fuel pump relay heats up and burns. I haven't checked the E-Box yet. I will check it today after reading reply posts in regards to my problem. Thank you everyone for all the posts. I will post later, the results of me checking the E-Box. Thx.
I checked the E-Box fan, and it was not working. After all this, it was a simple E-Box fan. Not the fuel pump, although I installed a new one, Meyle, on Ebay, $180. The E-fan, new, is $200. I heard someone took the fan housing apart, and replaced the electric motor, with one from Radio Shack for $7. Thank you all for your help.
i have the same problem of melting fuel pump relay.
I changed the fuel pump and the same problem persist. Does any body know what other parts to be changed in order to solve this issue?
Please find attached pics of the fuse box, the relay will not eventually burn and melt totally, but it will be damaged, and it will not make the engine start unless i change it with another one.
after some ride in the car the new relay will be damaged and car will stop till i change the relay with a new one.
once i turn on the engine for a period of time the Fuel Pump Relay will become VERY HOT.
no i don't have the original one.
The brown relay is for a MAZDA, and the blue one installed in the fuse box is DENSO,
3 blue relays was damaged over a time frame of 2 years and 1 brown relay over a time frame of 1 month.
But all relays go through the same symptoms HIGH TEMPERATURE.
When a relay gets hot, it doesn't mean that it is defective. Let the relay cool down and then reinsert it and you will see that it operates until it overheats again.
You probably have a wiring problem under the fuse box or the fuse box itself is damaged.
i did that exercise, the damaged relay will not turn on the engine even after cooling it down.
Do you have any idea how the relays are connected in the fuse box ?
09-23-2007, 10:35 PM
