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Just Keeps Cranking with No Start

5K views 40 replies 10 participants last post by  dramos 
#1 · (Edited)
05 ML500: Drove about 300 miles yesterday without any issues. On way back home, stopped to gas up, put about $2.00 worth of gas and left because the pump was very slow. This was around 1AM. When I got home I shut truck down to unload. When I tried to start again, it "sort of" started but it chocked and it all lasted a whole 5 seconds before it shut down. Thereafter, it would not start. It cranks very well but no start. About 1/2 hr later, it did the chocking thing again after a few tries. This morning it is back to just cranking. If I turn key and it starts cranking and then I let go of key, it just keeps on cranking. I haven't checked codes yet but I'd take any suggestions from anyone. It is a very strong solid crank, so I have ruled out the battery, which I just replaced a summer ago. Thanks.
 
#4 ·
Tach moves to just over zero. I thought it was bad gas also but I had just under 1/4 tank when I filled at a WAWA I have used for over 3 years - doesn't mean they couldn't have had bad gas.
 
#7 ·
Jeeez! You almost made me poop in my pants. In any case, I could not get a single fault code to show up when I checked this morning. Nothing, no error whatsoever. I'll have the truck towed to my local indy tomorrow morning. Whatever the issue is, I'll post here.
 

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#9 ·
Thanks. I don't drive the truck that much but she's a workhorse whenever I put her on the road, usually hauling family and cargo across many state lines along the east coast. I hope this current hiccup is just a fuel issue. A few older pics of the truck.

Original Purchase


Wheel and Front Grille Update


Snow Adventures in Garret County, Maryland
 

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#11 ·
Water is heavier than fuel so it will be at the bottom of the tank no matter whether the stations tank is full or empty. Most stations would have fuel water traps but obviously they may not tend to them often enough. Which would then allow a certain amount of water to be pumped.


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#12 · (Edited)
Update: My Hammer is Towed for the First Time

I had to have her taken to my indi. Hopefully I can report on progress tomorrow. I know some of us have more serious issues to worry about, but here are just two painful images of my beloved ML 500 - I know she'll be in great hands tomorrow - at a painful cost, I'm sure.

There She Goes

Dropped Off @ Indi - This Shop is Truly the Best for MBs and Bimmers - That's all They Do
 
#13 ·
UPDATE: Diagnosed to bad fuel pump. I bet it is the small amount of gas I put from that WAWA station which fouled everything for me. The fuel filter will also be replaced. I also asked them to clean the tank as best as possible without taking it out. Quote is $900.00. I plan to contact the WAWA station to see if there's anything they can do.
 
#16 ·
The fuel pump is designed to pump fluids. It will pump any fluid, including water, without being damaged. If it was diagnosed that the pump is faulty, then it was a coincidence. Pumps get faulty.
If there was water in your fuel tank, you would have had engine problems, not pump problems. Its a case of pump getting old & tired.......That's all.......
 
#19 ·
I went through that line of reasoning and found it flawed from a statistical point of view. Without dragging us into statistical details, I can't find evidence (on this forum) to assign the failure mode of the fuel pump to usage (basically #of starts or, more practically #miles driven). My truck has ~120K and I'd like to know of others who have had fuel pump failure at this mileage on their ML. My guess is that it's not a larger number.
 
#17 ·
Testing Fuel Pumps

Hi all,

In the future, to test a fuel pump turn the key to the last position before starting the car. You can hear the fuel pump initialize, a faint humming sound. If you don't hear the humming, check fuses then relays. If they are fine then the fuel pump is bad. This applies to all vehicles.

Take care!
 
#18 ·
Hi all,

In the future, to test a fuel pump turn the key to the last position before starting the car. You can hear the fuel pump initialize, a faint humming sound. If you don't hear the humming, check fuses then relays. If they are fine then the fuel pump is bad. This applies to all vehicles.

Take care!
Thanks for that additional info. Mine did not hum at all - I checked but never looked at the fuses.
 
#21 ·
I would think @ 120k miles your pump is aged.
You didn't use the WAWA station for the first time.

I'm on the side of Art that it is almost 0% possible that that fuel killed the pump so fast.
We would expect a big engine problem rather than just your fuel pump going kaput.
 
#22 ·
You and Art are absolutely right :thumbsup:. Spoke with tech earlier today and he confirmed that my fuel system is absolutely clean, no debris anywhere. The failure is electrical - looks like a connector on the body of the pump just shorted out - kind of worrisome since this thing is in the fuel tank and I never expected that. In any case, I didn't explode into many little pieces of Darkmanns, so we can assume with a high degree of confidence that the design is safe. I was thinking mechanical - electrical failure never crossed my mind. Tech also said that though he's seen this failure mode in other MBs, never on my model ML.

In any case, I'm a happier MLer today. Posted some pics .... well, just because I have them to post, and thanks for all your helpful hints. The Hammer is back in service.

Busted






 
#23 ·
Great to here it was just the fuel pump. Easier than trying to clean the fuel system out. Is the reason for fuel tanks not blowing up because there is no oxygen in the tank? When you have the sender units out they spark across the terminals. Always wondered that myself.


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#24 ·
I believe your instinct is correct that the reason it does not go "boom" is because there is no oxygen "inside" the gasoline to promote combustion. But there has to be some O2 in the tank (above the surface) because every time the tank is fueled, some "air" gets in. I have to go do some reading on this stuff:confused:
 
#28 ·
Jump fuel pump relay, put fused amp meter in place of fuel pump fuse and see if you have any current consumption, pump connected. Repeat with 80W light bulb instead of fuel pump. You may have voltage in unloaded circuit but no current.
 
#29 ·
I will give it a whirl and let you know what the results are.
What I do know at this point is that the fuse has continuity at both sides and 12v at both sides confirmed with multimeter and test light.
Relay was not jumped, but I have 3-4 brand new Hella relays on hand all the time and swapped it. I have not jumped the relay yet. While cranking my race mechanic was getting 12v at the pump, but the pump motor would not prime or spin while trying to start the engine.
 
#31 ·
Lolz
Witek that post was like mass hysteria.

That's how I saw the wreckers test used pumps.

@Noodles I really feel sorry for what you're going through. It would be provoking if truly they sent you a dead pump, that I seriously doubt.
I'm sure if you had ample chance you would have long solved this problem.
 
#32 ·
I did not want to post that we put 12v to the pump(s) from a small racing gel cell battery, but we did. I did not want others to try it.

My will is in order. LOL
I was on a 40 foot ladder checking the barn roof 10 days ago to make sure it be solid for the winter.

I dug out a brand new spare Bosch CKP just in case the tachometer moving method has failed me as a test. There were no codes
stored for the CKP.

Once this 36 snow event ends and the below 0º temps let up by Thurs-Fri I we are jumping back in.
We do need it back as the now the BAS,ESP and ABS lights popped up on 2000 ML320. I have yet to read the codes
and we have amazing winter tires, but still that has to be fixed. Just another item to add to the fleet of aging MLs.

There is an small small chance we can get the 1999 ML 430 pushed into the shop on Tues-Weds. In the interim
we might just commute on snowmobiles which is actually possible where we are located. :D
 
#34 ·
Breaking news.......We are now forecasting 12" of snow for Friday. Ugh I have got to get the 99 ML430 fixed before that. I do not like driving the wagon in deep snow even though it is a 4matic with great tires.

Meanwhile the current snow is still falling. I can deal with snow. It is drifting that will happen later tonight and into Monday that is going to take several passes every a few hours apart from each other to keep the driveways and walkways usable. With my recent luck the snow thrower will through a belt or the plow truck will blow a hydro line. I have spares for both, but it is no fun fixing this stuff when it is 4º F outside and howling wind.
 
#35 ·
I just got in from making the first pass. The winds will kick up at about 1am CT. I am going to have to do it again at about 5-6am and then later on Monday afternoon. Hopefully after that whatever fluffy snow was on the ground will be done blowing and drifting.
 
#36 ·
Well this got all kinds of weird.

Got a pump that primes. Then the tach stopped bouncing so a new Bosch CKP was installed. Tach now bounces while cranking.
However this thing will not fire up. I was there alone and really hurt my shoulder last week so that prevented me from checking
spark or seeing if the fuel pressure is building up with a gauge. The hose on the fuel pressure tool is not not long enough to tape
to the windshield.

I am going back down to check for the code P01570 or the AAM code B1703. I am not holding my breath on that being the issue.
because the ambient temp in the shop was at least 60º f and the ML was in the shop all night so that the 13" of snow we are getting
did not pile up on it. My mechanic is about to throw me and the ML out of the shop. (not really) but he is more aggravated about this
than I am. This just should not be that hard.

Also ordered a gas tank support brace that runs along the side of the tank to hold the tank straps. The one in the ML is rusting so badly that it scares me so a new one is going on the truck.
 
#39 · (Edited)
I wish I could, it was tossed in the dumpster and hauled away last Thursday.

I am trying to figure out the order of things. If I find code P1570 stored does anybody know if no signal is sent to the spark or fuel pump?
If that is the case we can push it outside while a I wait for the part. Nobody stocks one so it would be 2 days or so to get one if I order it early Monday.
That is all based on the assumption that the immobilizer has taken a permanent vacation.

Something is really tricking me here. I am going to run a quick test and then check the specific modules I can using DAS even though it goes into HHT mode for a beast this old. I can't print the results out at the shop, but I will save them as PDFs.

If it can not be fixed I am parking it as a spares truck and grabbing a used ML55. There is just a point where putting a lot of parts money and my race tech's labor/lift rental is just beyond worth it on a $1500 rusty ML with 287,000 miles. I already have about $450 in to this point with no results except a pump that does work when powered by an external 12v battery. We bought this old girl brand new in Dec of 1998 :(

Maybe I should pay a first class trip and have 43 or Witek fly in and have a go at it after the holidays. :D
 
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