Ronald King

Good evening, just replaced cps, fuel pump and fuel sending unit on my 06 e55 amg and it still shuts off after about 10-15 seconds of running. Fuel pressure jumps up to about 77psi upon starting, then drops off as if the car itself is shutting off the pumps. Could this be a key issue with anti theft or a faulty crank sensor? I'm stumped at this point. No check engine light, how ever I am now getting a low battery message. Charging it up now.

SICAMG

The fuel pumps should be running strong and not drop off. It will stall then turn pumps off in that order. If it's the other way around, it is the pumps that are shutting engine down due to lack of fuel. Check your fuel pump relay if fuel is the problem.

Ronald King

In the trunk yes? Bottom or top relay out of the 3 that is below 30amp fuse? All 3 relays and both fuses look good as new. No melting, burning or corrosion. Swapped relays with same symptoms

rapidoxidation

I could be wrong but IIRC when you turn the key the fuel pump fires up for a few seconds to pressurize the system then shuts off. When the car starts, the oil pressure sensor tells the computer the engine is running and the pump gets turned back on. If the engine quits like in an accident then the oil pressure drops and the pump is turned off.
First thing I'd check is power at the pump itself. Sure seems like it's getting the initial call for power when the key is turned on, but then the pump isn't being told the engine is running and never gets turned back on, as confirmed by the pressure gauge on the fuel rail. Work backwards from the pump. If you're handy with electrics, you can bypass the fuel relay to energize the pump manually. You can test the relay socket for the signal to turn the relay on. You can make sure there's power on the hot side of the relay.
My first thought is a bad oil pressure switch. Sounds like your relay and relay socket are good, but the relay isn't being told to turn on once the car is running.
Let us know what you find out.

knowbenz

If your battery light is coming on make sure the voltage is good at the pump and your alternator is functioning.

Did you replace the fuel pumps in an attempt to fix this problem or did the problem start after replacing those components?

Ronald King

I'll try bypassing the relays today. Removed both of the lower relays (3 in total) and no fuel at all. Installed the middle relay, still no fuel at all. Installed bottom relay, and back to square one, starts then shuts off. Battery is charging now, was at 11.5 volts. Jumps up to 13.8 when revving to about 3000rpm. Voltage regulator maybe? Problem began before replacing any parts at all. Got stranded near an autozone, and thought it was the cps. They only had a duralast brand one in stock, installed and had the same issue. Bosch cps on order. Replaced pumps, same issue, followed by the sending unit and still the same exact issue. No codes to pull as well (icarsoft mb2 diagnostic tool)
Battery is charged up now, pumps are priming up to about 75-78 psi, but now car just cranks and doesn't start at all. Bosch sensor will be in Thursday. I changed the oil the prior night before this issue began. Car ran perfectly fine, ran the oil level check function afterwards to verify level. I'll get back to it after work to test voltage at the pumps.

bbirdwell

First problem is the battery voltage is far too low. Shouldn't be under 12 volts at rest and even that indicates a discharged or old battery. Low voltage plays havoc with the distributed digital control system in our cars. You indicated the problem started before replacing the pumps and filter so the first place I would now look is at the battery.

Following info is for a E55 with build date on or after 1 June 2005. Earlier builds only one fuel pump relay.

Fuel pumps and air pump are provided power from fuse f82, 150 amps, in the pre-fuse box in the trunk. Both fuel pumps are protected by a 30-amp fuse located next to the two relays. The air pump is protected by a 40-amp fuse next to the relay.

Both fuel pump relays main power source is a 6mm square red-yellow wire. Relay 1 output is a 2.5mm square red-blue wire. Relay 2 output is a 2.5mm square red-black.

Both fuel pump relays' solenoids have a constant-on 12 volts whenever the key is on. That wire is a 1.5mm square red-blue wire that connects to the rear SAM, fuse f43, 15 amps.

Fuel pump relay 1 is activated by a 0.5mm square brown-blue wire. Fuel pump relay 2 is activated by a 0.5mm square brown-green wire. Since the solenoids always have power applied when the key is on, I would hazard a guess that the two relays are tied to an open-collector circuit in the rear SAM Motor Electronics that connects the signal to ground to enable power to flow.

Air pump relay main power source is a 4mm square red-violet wire. The exiting wire to the air pump is a 4mm square red-black. Solenoid power wire is a 1.5mm square black-grey wire that ties to the same power source fuse f43 as the fuel pump relay solenoids. Trigger wire is a 0.5mm square gray-yellow wire connected to the rear SAM.

You can force the fuel pumps to run by installing a jumper wire between pins 30 and 87 of the sockets but that doesn't address the issue of why the fuel pumps prime for one second but do not reactivate once the engine is running. That points to a malfunctioning electrical bus or lack of signal input to the system to indicate the crankshaft is rotating (crank and/or camshaft position sensor).

If you installed the latest version fuel pumps (P/N ends in 00-00), ensure you have the adapter cable installed. Old pumps had power on pins 1 and 3, new pumps have power on pins 2 and 3. The adapter cable takes care of that.

If your main battery is not holding 12.2 volts or better, I recommend replacing it. Remember, when disconnecting or connecting the battery, have the key fob out of the ignition or, if keyless-go, away from the car.

Please post your solution when found and good hunting.

Pmarino

Sounds like spark not fuel.... You can always double check that it's not fuel by removing the air filters and spraying some carb/TB/brake cleaner into the throttle body and crank it over and see if she wants to run. I would also check the fuel sending lines and make sure the connections and return are in place. My money is on crank and cam shaft sensor and hopefully not the SAM is involved.

[QUOTE=bbirdwell;7311569
That points to a malfunctioning electrical bus or lack of signal input to the system to indicate the crankshaft is rotating (crank and/or camshaft position sensor).
[/QUOTE]

C32owner

This is your problem, as mentioned above by BBIRDWELL already. I had the same issue.
If you installed the latest version fuel pumps (P/N ends in 00-00), ensure you have the adapter cable installed. Old pumps had power on pins 1 and 3, new pumps have power on pins 2 and 3. The adapter cable takes care of that. Swap the power pins and your in the business mate. Ridiculous issue and don't understand why Mercedes swapped it.

Ronald King

Swapping the pins on the connector for the fuel pump nearest to the access hole did the trick, appreciate it guys! Fuel pressure is holding steady at 83psi

knowbenz

Haven't seen any damaged 55k motors from that but seen quite a few m113/m112 blowing a hole in intake from people spraying **** in the intake

Pmarino

In what way? Trying to clean out carbon, yeah spraying **** loads will cause a problem, I agree. But a couple of shots to test for fuel starvation.....

knowbenz

I think the problem comes from the average guy not fully understanding what a "couple shots" means. I've never in my life had to spray stuff in the intake of a modern car to test for no fuel except maybe some real old carburated cars. Fuel pressure gauge and a volt meter are much safer options

topendusa

I had a similar issue when I replaced my cps, turned out to be a bad cps. I got a new oem bosch and installed it, no issues since.

C32owner

Sweet glad it worked mate. Can breath again and enjoy it

chadbennett

2006 cls55 AMG has the same problem and shuts off
My son has a 2006 cls55 AMG and it is having the same issue where it will start for about 10 seconds and then shuts off. Read it might be the cps so I replaced the cam position sensor and the crank position sensor. Not the fix. Had a friend come over to help diagnose and seems to be a fuel issue. Fuel relays click when key turns on so they seem fine. Opened the back seat and the fuel pump turns on and right before it shuts off, he said that it feels like it stops pumping fuel. Sprayed starting fluid into the intake and didn’t shut off. So now it seems to be confirmed as a fuel issue but not sure where to go from here. Do I replace the fuel pump and if so, the drivers side or the passenger side. Or do I start somewhere else because clearly it’s not getting fuel

Pmarino

I don't know the CLS platform but,,,,,, A stock M113k has a schrader valve on fuel rail easily accessible toward the front on the passenger side.(Rt side). You can attach a fuel pressure gauge and check.
If the 06 CLS platform is the same as W211 with saddle tanks you'll want to replace the pump(s) and sender unit. Usually the filter clogs and pump draws too much amperage and burns out. Nasty job, but not complicated, drain the fuel tanks as much as possible before digging in
Do a search with BBirdwell, you'll find many threads related to the W211 fuel system.

UncleBenz55

If it's a modelyear 2006, those have two fuel relays and on engine start, it runs both pumps with fuel pressure at 5,5bar and a few seconds after start it shuts off the second pump and the fuel pressure should be at 5,3 bar. As stated by Pmarino, there's a service port on the fuel rail, where you can connect a fuel pressure gauge and measure the fuel pressure.

bbirdwell

Sounds like a fuel pump electrical issue. I've repaired mine a total of three times. Relay, socket, harness, and connectors melt. Obviously, bad for the car. Repair, replace, upgrade as appropriate. Every time I corrected the weakest link, I then found the next weakest link...

Read the following:
https://mbworld.org/forums/w211-amg/...intenance.html

https://mbworld.org/forums/w211-amg/...ify-parts.html

bajlo-cls55

Hello guys, i have the same problem.

I ran out fuel on my cls 55 2005. Next morning, when i wanted to start my AMG it died after 15 seconds. I checked my relays. I have 3 relays in trunk. two for each fuel pump, one for air pump. All rellays were fine. I opened cover rom passanger sides and found out that one of my pump is dead and second pump dies after 15 seconds when car is on. I switched connector (i plugged functional pump to the port where was dead pump plugged in). Immediately when i started the car, it runs without problem, but knowed that second pump is dead. I ordered one, everything connectet and try started the car.

First position- both pumps runnig.
Started the car- both pumps running
After 15 seconds- one of the pumps is switched of.

Is it really normal ?@UncleBenz55

This 2005+ year runs normally on one pump? When does the second pump starts if it starts? When I drive hard and fast? Because earlier e55 pumps should run both together anytime as I know

Thank you guys.

Have a nice day

UncleBenz55

Modelyear 2006 (iirc built after June 1st 2006) has one relay per pump. Pre 2006 has one relay for both pumps. On my car, it shuts off the second pump after a few seconds. The second pump is engaged at around 3000 rpm.

What is your fuel pressure at?

bbirdwell

Nice nugget of information to have concerning the second fuel pump actuation.

bajlo-cls55

@UncleBenz55 my cls55 is buil in June 2005. Maybe cls´s have two relay system earlier in comparison with E55´- 2006?

regarding to the pressure, i have not measured it yet, but i have to. Obviously today i will try REV my car to the 3000rpm. Do you think it will engage second pump also in Parking Position? Because limiter in "Parking" is set max. to 3000 due SC clutch i think .

UncleBenz55

Sorry I mistyped it earlier in my message. Modelyear 2006 is from June 1st 2005. So yeah yours is MY06.

I don't think it will use the second pump in P, since the SC isn't engaged as you said.

bajlo-cls55

So you think, when i measure pressure on rail. (5,5bar after start up, 5,3 after few seconds when one of my pumps is off) is everything alright?
How can i test it otherwise? For examle when i floor the car? I´m now little bit calmer, when you have said that second pump is turned off after few seconds. I have thoutht that something is wrong