bbirdwell

2005 E55 with 92,000 miles, factory stock.
-The car’s engine died driving down the highway Wednesday evening but restarted after 10 minutes on the side of the road. I replaced the Crank and Camshaft Position Sensors as soon as I arrived home. The next day the engine died on three separate occasions.
-I ran diagnostic tests on Wednesday and Thursday. Tests resulted in no diagnostic trouble codes, no bad sensors, no bad modules; according to the computer, all was well.

Background:
-Car’s engine died Wednesday evening while driving. Pulled off road, waited 10 minutes (engine would not restart at 1, 3, or 5 minutes), restarted engine, drove home, and replaced the Crank and Cam Position Sensors. I ran the adaptation on the Crank Position Sensor but only had time to adapt Load Range(LR) 1 w/ Speed Range(SR) N1, and Load Range 2 w/ Speed Range N1. I did not have time to adapt LR1 w/ SR N2 or SR N3 nor LR2 w/ SR N2 nor LR3 w/ SR N1. Despite this, a non-adaptation should display symptoms of a mis-fire, not (I think) engine failure.

-Thursday the engine just quit (with the wife driving it on an elevated expressway downtown! ) after an approximately 30 minute drive. The car restarted after 10 minutes. At that time I arrived and began driving it towards home. Approximately 25 minutes later the engine quit again. Wait 10 minutes, restart engine and continue. Approximately 18 minutes later the engine quit again. Wait 10 minutes, restart engine, and this time made it to the house. FWIW, the Wednesday evening failure was ~25 minutes into the drive home. Everything seems to be in the 20-30 minute range. No spitting, no sputtering, the engine just quits.

-Looking at the maintenance records, I see no sign of fuel filter replacement or any other maintenance on the fuel system. Since I was planning on replacing those items at the 100K mile service, I ordered the fuel sending unit and fuel filter assembly and will replace upon arrival next week.

-The only way I can think of to see if the engine failure is caused by lack of fuel pressure and/or spark is to drive the car until it quits, then check the fuel pressure with my mechanical gauge and pull a plug wire and see if I have spark. This also means I need a co-driver who doesn’t mind getting stuck on the side of the road while troubleshooting the car.

-I have the troubleshooting guides and will begin implementing those. My worry is the engine will run fine in the garage so if it is a fuel or spark issue it won’t show.

Ideas? Suggestions? (Besides keeping to road trips under 25 minutes.)

Cross posted at other forum.

biker349

my guess ignition module. it happened like that on my car. also could be accelerator pedal. but that should throw a code. ignition module seems to be intermittent and on mine didn't throw any codes, but i would pursue the fuel system first.

bbirdwell

Thank you. I'll pull out the schematics, locate this module, and be prepared to replace just in case the fuel system is not the issue. The bit about "intermittent but no code" is a valuable piece of information. Thanks again.

biker349

actually thinking back i got a p300 code random misfire. then the code went away. i thought it was my coils, but the dealer checked the ignition module and found an intermittent fault.

Ausmbtech

There is no "ignition module" on the 55K, it's unique to the V12's.

If you have already done the crank and cam sensor then they are the most common causes.
Do you have a fuel pressure gauge? If you do then check the fuel pressure when you it wont start. Even though there are 2 fuel pumps the engine must have both functional to be able to run. If you have already order them then replace them and see how you go. I would also suggest replacing the fuel pump relay as they are cheap but difficult to catch out when they have an intermittent fault.

Doe it only occur with a fuel level of 1/2 tank or lower by any chance?

Otherwise there isn't much else that can cause a stall/no start condition that recovers by itself after a period of time.

bbirdwell

Thank you for the advice.


Fuel pressure gauge is now plumbed to the system fuel rail. I realize this is the way to go but I cringe thinking of driving my car until it just quits and puts me on the side of the road.


First failure was at 1/4 tank fuel; next three were on a full tank minus 60-90 miles.


Fuel pump relay is on order; cheap, easy to replace, and hurts nothing. Easier to have all parts on hand rather than waiting on them one at a time with at 3 to 5-day intervals. I figure I'll swap the relay, pumps, and filter at the same time, then take the car on a test drive with fingers crossed.


Until then, I'll be exploring options for a replacement ECU just in case. Either go new ($$$$ yikes!) but with the latest software and hardware, or seek a used unit with a new chip in it with my car's data copied and loaded into it. Arguments for both paths.


I much appreciate everyone's input.

bbirdwell

Bottom line up front: What is the proper fuse size for the fuel pump relays? 30 amp or 40 amp?


Been a month since my last post but I've been a bit busy with summer field exercises and missed opportunities.


See photos attached. I replaced the fuel pumps and filter/regulator as the car is approaching 93K miles and the service records show no previous service. See https://mbworld.org/forums/w211-amg/...ml#post6465258


I decided to replace all relays (two each fuel pump relays plus circuit 15 and circuit 15R relays) that might even be associated as they are inexpensive yet can cause failure of the system.


Note: I can only test by taking the car for a test drive and I really, really hate finding a failure by being placed on the side of the highway or blocking a traffic light.


Pulled the right rear panel in the trunk. Observe the fuel pump relays are different and the fuses are different! No record of this in the maintenance files available so I believe this occurred in the first 3 years the car was owned by "the Californian" prior to the repossession and subsequent resale of the car which led to my ownership.


Both relays that were in the car are the original superseded A002-542-13-19. I'm installing the replacement relays A002-542-72-19. I'll need to confirm I have a good connection on the socket to which the relay connects. The last photo shows the *very* poor connection which led to a voltage drop, increased temperatures, and melted connectors.


Engine failure issue is not yet resolved but I'll continue to update as I work to get this car back on the road.

UPDATE: Per Shardul, the fuses are the correct ratings and in the correct positions. Thank you, Shardul!


Cross-posted at the other forum.

bbirdwell

Removed and replaced the fuel pump relay and its socket. Appears that a dirty fuel filter plus partially-clogged pump inlet screens caused an overcurrent condition of the fuel pump motors. Fuel pump relay overheated and literally melted the socket.


I cut out the old socket, crimped and soldered new connectors onto the wires, and installed a new relay.


FWIW: I also learned that only one of the two relays is for the fuel pumps. The other relay is for the electric pump located under the left-front headlight.


For reference, here are the part numbers I located.


2005 E55 fuel pump relay cross-references:
MB 002-542-72-19
Hella 4RA 007 791-011 (Auto catalog)
Hella 007791011 (General catalog)
Bosch 0 332 019 103
Tyco VF4-11F11-S01


Replacement relay socket:
Hella H84989011 (Amazon, Summit Racing, etc)


Terminals (purchased locally at industrial electric supply house but available through mouser.com):
10-12 gauge 0.250” (6.3mm) female,quick-disconnect, non-insulated with locking tab.
14-16 gauge 0.250” (6.3mm) female,quick-disconnect, non-insulated with locking tab.
Note: the relay coil ground wire is18 gauge and must be doubled over to use the 14-16 ga terminal.


You will need a good wire crimp tool.


Relay positions in the photo are reversed from the OEM factory position. You should ensure which relay powers which circuit before performing any work.


Cross-posted.

bbirdwell

Relay contacts were lightly pitted from arcing caused by opening and closing of the relay but still only indicated 0.6 ohms when closed. In the future, I intend to replace this relay whenever the fuel filter is replaced. Catalog rates the contacts at 100,000 cycles but a milliohm contact resistance should not have produced enough heat to melt the relay and socket.


In 85 degree F ambient, my IR thermometer measured the hot spot on the new relay at 138 degrees F this morning. To melt the plastic, the temperature of the relay would have to be over 300 degrees F.


(Edit. Temperature data this evening. Outside air temp ~ 95 degrees F. Trunk ambient air temperature 117 degrees F. Fuel pump relay hot spot was 171 degrees F.)


These are only two data points with both indicating relay temperature is approximately 53 degrees F more than the trunk ambient. Having suffered through this failure, I am looking at "and/or" options.


Option 1 is a DROK voltmeter/ammeter readout mounted in the trunk and powered from the fuel pump relay coil input. Option 2 is a thermocouple powered by the relay fuel pump output. I am installing option 1 and ordering option 2 because I never, ever, never want my wife stuck again on the shoulder of the highway on an elevated expressway downtown in heavy traffic.


Some may consider this overkill but I prefer to have a system that I can monitor just by opening the trunk while the engine is running. Amperage too high (>20 amps) or relay temp >225 degrees F means it is time to pull maintenance on the car. I'd much rather take the car down for maintenance on my terms than have to potentially flat-bed the car 200 miles to a dealer (or receive a tense call from my wife that she is on the side of the road in a very dangerous place).


Hope this helps someone in the future.

biker349

thanks for sharing.

BoostedAero

Is there anyways to share a how to/final product PIC? I have learned on these cars do it "perfectly or nothing" works right

bbirdwell

Attachment has photos of the finished product that I use to check fuel pump voltage and amperage at each oil change or major maintenance. Schematics available on the Amazon website show you how to wire the box. Look at several until you find the correct schematic. Be advised that MB WIS states that if the combined amperage is >20 amps, fuel filter should be replaced (or words to that effect).

Next post has attachment.

This is the DROK meter of which I purchased two. Available on Amazon for about $16 each.

DROK®0.28'' DC4.5-30V 50A Voltage&Current Digital Multimeter Tester 12V/24V Volt Amp Gauge Panel Monitor Integrate Voltmeter&Ammeter with Red/Blue Dual Color Display Equipped with Current Shunt

bbirdwell

PDF attachment.

Cut the cable per schematic, place DROK meters inline. Whenever you perform maintenance, pull rear seat, pull harness from fuel pumps, insert measuring device inline, start car, log data. If all looks good, turn off car, remove measuring device, reconnect original harness, install seat. Done in 10 minutes and that beats being on the side of the road in rush hour traffic.