Fantomas

2004 E55 with 87k miles. It started with fuel pooling up on the pump cover. Replaced the pump cover with aftermarket ebay one and it ran ok but had some slight hesitation. Decided to buy a new OEM new style sending unit and new style OEM fuel pumps along with the conversion cables for each side, installed those and the car continues to crank but wont start. Replaced the crank shaft position sensor with Bosch sensor, no change. I noticed that the sender side of the tank was empty while the pump side looked half full. Grabbed 5 gallons of premium gas and poured half of it down through the gas door and the other half I removed the sending unit and poured directly into the driver side of the tank, no change. I haven't checked fuel pressure but I can hear the pumps priming, running while it cranks and fuel squirts out of the schrader valve under the hood. There are no codes in the engine computer or other systems.

Any ideas what to check next?

James Robert

Being that the car was running before...I would say its related to the fuel pump covers you put on. I would go put key in position 2 and depress the Schroeder valve at the front of fuel rail and see if you are getting a large volume of fuel rushing out assuming you don’t have a fuel pressure gauge. Fuel pressure should be about 55-60psi if you do. If you do have fuel pressure go check your wiring against the original harness/lid. Also make sure your hose attachments inside the tank that feed pump are attached.

coupesedan

pull spark plug lead connect to spare plug, crank and see if you have any spark. if no then CPS is highly suspect

James Robert

No need to pull the plugs when he already replaced the CPS. The car was running before he messed with the fuel pump covers. I would double check my work if I were him.

Fantomas

Fuel pump covers are oem, same as what the dealer would install during the warranty extension. Adapter harnesses are installed on the pumps and sending unit. Everything is oem, I took off aftermarket parts.

I'll be buying a fuel pressure gauge later today to test it.

James Robert

Your best bet is to check fuel pressure and make sure you are getting the correct pressure. If you are then it’s time to look into spark.

kevm14

Fuel pressure should be 77 psi. At least it is on my 04. If your rail loses the prime (mine seems to overnight) then it may take more than 1 prime to get up to the proper pressure. But cranking for a few seconds should do it (mine starts fine anyway even after sitting).

James Robert

Fuel pressure should be 55-65 max. 77 is wrong.

kevm14

No that is not correct. Where are you getting 55-65 from? These run in the 70s with a fixed (non-vacuum/boost referenced) in-tank regulator. I don't know what spec is but from what I've read 77 is about where it is supposed to be.

James Robert

I’m a master technician at Houston greenway. I will tell you it’s 55-65 psi max on most of our cars that are port style injection.Not sure where you got 77 from? Look up WIS.

Edit : it is in fact 74 on the AMG vehicles. I stand corrected. Apologies.

kevm14

Now show me yours.

James Robert

You have an issue with your pressure or gauge my man. That is high.

kevm14

This thread says 72.5 is spec: https://mbworld.org/forums/w211-amg/...regulator.html

I don't have access to WIS right now....but that is a hell of a lot closer than "55-65."

This thread says he sees 5.3 bar which is.....77 psi: https://mbworld.org/forums/w211-amg/...ml#post6226991

This thread says the regulator is set to 5.1 bar which is 74 psi: https://mbworld.org/forums/w211-amg/...ml#post8080104

Did I just teach a Master Tech something?

James Robert

WIS says 65 at idle. I will check my car tomorrow. 77 seems a bit high in relation to what WIS says.

James Robert

Lol you are going off of thread searches. I am going off real world experience.
Shardul should chime in. 65 is what we are looking for when diagnosing cars for no starts. To be honest as a tech when we see fuel pressure over 45psi we generally don’t look into exact specs. To me 77 seems high but again I work on every make and model that Mercedes has so maybe 77 on an 04e55 is correct.... in general 55-65 is where it should be on w211 w219 w220 w215 w230 etc....

kevm14

That's what I thought - but not all cars are the same, so you shouldn't assume. I also agree 77 "seems" high but apparently that is what it is supposed to be, because that's what everyone else's seems to be. Not sure why WIS says 65. Remember it is not boost referenced so the port injectors work against manifold pressure under full load/RPM. I also wonder about using such a high pressure from an under hood heat perspective (heat soaking the returnless rail under very low flow fuel conditions).

Supposedly my car has a Eurocharged tune BUT I can tell you fuel trims are like damn near zero.

James Robert

I have a eurocharged tune as well and noticing the same. I Just changed set up to MBH long tubes with X pipe,550cc injectors and a 77mm pulley. Just put in new MB fuel tank with integrated pumps per the campaign a few months back. Once I get her back together I’m gonna check to see what my static fuel pressure is as I’m very curious now. My co worker has a stock one And I’ll compare. Both are 2005

Fantomas

Just tested fuel pressure, has 75 psi ignition on, holds 65 ignition off and jumps around 60-90 while cranking. Looks like I don't have spark or the injectors aren't firing.

Fantomas

IMO anything over 45 should be running, 65 is probably with an old fuel filter while 75 is what you should see with a new filter.

Looks like I can put my seats back and reassemble the trunk, fuel system is fine. I'm going to recheck the CPS and see if I have RPM signal in the scan tool then potentially pull the 1 month old CPS out of my C55 that runs great and put it in my E55, surprisingly the CPS DIY on the C55 is a much bigger PITA than E55 in spite of the supercharger.

coupesedan

Pull a lead get spare plug crank and check

kevm14

The regulation happens after the filter. Shouldn't vary anywhere near that much. In fact the only time you should ever see fuel pressure go under spec is when the pumps can't flow enough for the demand which would only occur under very high output situations, not idling in your driveway.

James Robert

You got a brand new Bosch CPS? Looks like your fuel pressure is good and it’s highly unlikely all 8 of your injectors stopped firing unless your ME has an issue. I would check to see if you are getting battery voltage into one of your coils (I believe it’s pin 2) and if you are I would see if it will fire during cranking. This rules out any faulty z splices and ensures you have proper primary voltage. You can also backprobe an injector pin 2 to see if it’s receiving firing signal from ME.

i agree I would re check that CPS and make sure it’s seated correctly and what not. I have seen a faulty knock sensor cause this but it’s extremely rare. Usually it’s the CPS causing ME to pull ignition.

Fantomas

Looks like cranking the RPM remains at zero on the live data of the scan tool. I recall this number being around 150rpm during cranking before replacing the CPS. Going to put the old CPS back.

EDIT: with the old CPS in I saw cranking RPM of 160, I think I did it wrong on the new one so I assume neither is the problem.

Fantomas

Pulled the plugs, never seen this before in my life.

Fantomas

At least two of the plugs were like that on the pass side of the engine, going to replace all 16. Is there a fuse for the coils that could have blown?