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2004 CLK500 ran but sat year and a half, new fuel pump / sender but not getting fuel
Car was my mom's, she bought it new in '04. Has 77k miles, and ran great until it was parked over a year ago due to tags. I replaced the battery, fuel pump, sender, fuel pump relay, and checked all fuses. I also thoroughly cleaned out the tank and put in 5 gal of fresh 93 octane. Cranks but doesn't get fuel. I'm out of funds to keep throwing parts at it, and out of 7 euro car shops I called here in San Antonio, only 1 would even look at it for a min $300 diag fee. Car also needs 1 tire, plus would need a tow there which is too much for us right now (been out of work sick for a few months, finally about to go back to the office). I remember my mother buying this car at MB of San Antonio new for around $60k, it would kill me to have to sell it for <$1500 not running. So I wanted to see if any experts have any ideas on what I could do next?
Exterior is in pretty good shape, 7/10
Plastic hoses in tank were toast Interior's in great shape
Last edited by a454ci; Apr 7, 2024 at 03:44 AM.
Reason: Censored lic plate number from photo
I think maybe my rear SAM may be dead? Not sure how big of a job that is but looks like the part is about $300 refurbished. Any input as to how I can check it would be greatly appreciated, I'm going to try everything I can to fix this car.
Ok, so I tested pins 2 and 5 on the 5 prong connector (which I think are to the pump per some diagram I found online), and it gets 11.8v when I turn the key but the pump isn't kicking on.
Not sure if I read this right, but I think 2 and 5 on the 5 prong connector (which I think is X36/3 towards the top?) are to the pump (M3), is that right?
I tested pins labeled 2 and 5 on the larger 5 prong connector to the right
Last edited by a454ci; Apr 7, 2024 at 07:37 PM.
Reason: Adding info
OK, update: fuel pump is actually priming after all, still not getting a reading on fuel level. Next steps I think are to replace the fuel filter then check fuel pressure at the fuel rail? If it won't run but just cranks, would it still give me a code if the crank / cam sensors are bad? And is it dumb to ask if unplugging the battery for a while could make any difference? (Resetting the computer or something?)
2009 SL550 Roadster Diamond White, 2008 CLK550 Coupe Obsidian Black
I had some weird crank no fuel issues as well last year for a while. I've attached the link below for my resolution. I had to change my rear sam a second time because it got shorted (The first time it happened they changed the passenger side fuel pump as well back in 2021) and had to replace the connector as well and even replaced the connector that goes to the sender. My actual issue got resolved when I adjusted the power pin on the sender itself, but I never replaced my original sender behind the drivers side, just the pump behind the passenger side, so that's obviously not your isse.
I had some weird crank no fuel issues as well last year for a while. I've attached the link below for my resolution. I had to change my rear sam a second time because it got shorted (The first time it happened they changed the passenger side fuel pump as well back in 2021) and had to replace the connector as well and even replaced the connector that goes to the sender. My actual issue got resolved when I adjusted the power pin on the sender itself, but I never replaced my original sender behind the drivers side, just the pump behind the passenger side, so that's obviously not your isse.
Awesome, thank you soo much for the link! That's great, I just ordered a fuel pressure tester. Still have to figure out the guage not working, but if I can get it to fire up then I'll be stoked! Thanks again for the links!
2009 SL550 Roadster Diamond White, 2008 CLK550 Coupe Obsidian Black
Originally Posted by a454ci
Awesome, thank you soo much for the link! That's great, I just ordered a fuel pressure tester. Still have to figure out the guage not working, but if I can get it to fire up then I'll be stoked! Thanks again for the links!
I had an issue with the fuel gauge as well when I let it run down to a gallon or so left in the reserve tank. The gauge wouldn't move at first so ran a bottle of techron through it on the next fill up. Not sure if that helped or if the level sensor had gotten stuck or something after getting down so low the first time.
2009 SL550 Roadster Diamond White, 2008 CLK550 Coupe Obsidian Black
Also, the first time I had this issue back in 2021, my rear sam was salvaged by cleaning the terminals, but the second time it got shorted it had to be replaced.
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