Hello. Firstly I'd just like to thank all in this community, as without the help/posts/threads on here, I wouldn't have got even this far with the repair's on my E55. So thank you all!

Hopefully someone can steer me in the right direction.
I think I may be having a overheating issue whereby the car is pulling timing when it heats up, but its happening very soon after its started up. It feels very fast early morning, and I never get that surge of pull throughout the rest of the day. Even when parked up from work.
This is my first and only E55, so comparing the power feeling to a fully operational car is difficult. the car is quick, just to me it doesn't feel 'amg' quick. I've driven a S63 2007 and that thing feels amazing. But this car just doesn't blow my mind in power as i expected it to be, and how other describe their cars on here. Can someone help me out here? I have a feeling the SC just is not engaging. I also struggle to get over 20mpg. Is that normal? I understand when the ECU pulls timing, it dumps extra fuel, my exhaust tips are black somewhat. Is this normal?


Recent stuff done to the car by myself:
- Water pump
- Oil change
- Thermostat
- Pulleys
- 16 spark plugs + new cables
- Intercooler Pump - Bosch (I have fitted a brand new unit from FCP, but is it possible that this could still be at fault?)
- Radiator + Coolant
- Belts
- Valve Cover Gaskets
- Full tranny service
- Brake Disc's (front) + Front Pads + Rear Pads

I can post some images of data logs but please let me know which logs would help diagnose this issue.
I just really want to feel my supercharge kick in, and i fear it is not!

 

Definitely need logs, mainly MAP, timing, and IATs. Fuel trims would be good too on non-WOT runs. Lastly - any history of fuel pump/filter replacement?

 

Thank you for your response.
I will get those logs up asap. I've gone through the paperwork from the previous owner and can not see any evidence of fuel pump or filter replacement. Since purchasing it, it has always had a slightly 'lumpy' idle. Is fine to drive and no rough idle when in gear. No hesitation or jerking either. I drive it to work everyday.
Secondly, if the issue was related to the fuel pump/filter, why would the car feel very fast on early mornings?

 

Sounds good, data is always key! It would be ideal to have fuel pressure readings too, not sure if you have a mechanical gauge with a long enough line to check while driving (the ECM does not show fuel pressure so you'd need to plug in at the end of the rail). Regardless, this is an issue on these cars and some say doing the pumps and filters every 60k miles isn't a bad idea, not sure how long you've had the car. Low fuel pressure can cause the car to run too lean, which can feel more powerful (although dangerous) and then could be correcting itself. That's why looking at fuel trims may help too if they are too high/too much correction.

Hope we can get this solved for you! I've had my share of hard to trace problems on my car and know how annoying it is. These cars are worth it though once they are sorted

 

The straight line is at WOT


The increase and peak is at WOT




here are some data graphs for you to analyze. No idea if there are what you need to see. If not, please let me know what else I can get you. I'm use the 'torque' app.

 

What we'd probably need to see is a graph of all of these happening at once, it's too hard to tell if any of these parameters are off when they are all happening at different times. Maybe get a few runs (full throttle, and part throttle) of MAP, Timing, and RPM. Your IATs look good, and while you have a spike in short term fuel trim that is normal under certain conditions and your long term looks ok so I'd venture to guess your A/F sensors are probably fine (although they can be another source of power loss too...). You're definitely making boost based on MAP readings so the supercharger is engaging, and your engine temps look just fine, most of our cars run around 190.

I forgot to ask - the car is stock, no modifications?

Under ideal circumstances you'd want to check physical fuel pressure, as well as your air/fuel ration with a wideband but that of course requires more diagnostic equipment and fitting. And I'm assuming this power loss complaint existed before you did things like spark plugs and wires?

 

Thank you for your input.
My assumption of the SC not kicking in is down to a few things. I just don't feel that surge of pulling power. I cant hear the whine. I also feel the engine 'dial back' somewhat when coming out of a corner, 2nd gear and flooring it, as if the timing is being adjusted for some reason. It just feels sluggish and lazy. A TCM reset has been done with removing the battery overnight etc. Also, from reading other forums on here, flooring it in 1st gear with the traction control off should spin the wheels, this does not happen. car takes off like i would expect a e500 to do.

Car is stock, no mods. I believe in keeping things how they were intended from factory. Previous owner had it serviced by MB up until around 100k. around 16k of service done by an indy. I purchased it at 116k in Feb 2021. When I test drove the car, it was very very lazy feeling, and would almost struggle to climb up hills. After reading on this forum, I opted to change the IC pump, and carried on changing parts as this forum had recommended. The car feels much more responsive since purchasing it, I would assume its massively helped by the new spark plugs and oil change. But As i purchased it with a power issue, and I've never driven another E55, I have nothing to compare it to. I live in California, I understand these cars dont like the heat. But in feb, it wasnt that hot and it still produced low power feeling....

I'll get those graph data combined for your evaluation. Thank you!

 

I don't see MAP on there. I see MAF (calculated) and the peak does not look like 469+ hp if he was at WOT. Is there a way to graph knock retard?

 

What's the option I should be selecting for MAP to be recorded on the 'torque' app?

 

Something that refers to intake air pressure.

 

I have the option for 'intake manifold pressure'? 'turbo & boost vacuum gauge'? mass air flow rate? throttle position sensor (manifold), timing advance, and then fuel trims (long+ short) and o2 bank sensors.

I think having all of these graphs show up at the same time will be crazy so if you guys could advise which you would like to see, I'll do a WOT run and then a normal highway run today.

Thank you very much for your input so far.

 

Yes the turbo and boost vacuum gauge on the torque app will show your boost levels. Select IAT intake air temperature to monitor at the same time. If you can the degrees timing to. However the OBD read rate is very slow but can try. See if you can find a nice stretch of road and do a 3rd gear pull say from like 3000rpm up.. Will give a decent amount of info

 

OK, perfect. I'll have this done shortly. Thank you!!

 

At idle



these are runs I did last night, car was up to temp. All runs done from complete standstill, S mode for gearbox.

 

This was the largest, longest run.
these runs we're done this morning

 

If I am reading this correctly I don't see any supercharger boost. Though the units are all fighting each other which makes it hard to see what is what...but I read the first one as your pressure never goes above ~90kPa and you never get into boost based on the yellow one. That's what I see.

 

Yep that's what I see too - no boost at all. This is more than just a timing adjustment, something is preventing the SC from engaging.

This may seem obvious, but have you thoroughly checked all the fuses? There are a few that can affect the ECM power control, and of course the IC pump one. When you replaced the pump, did you test it after? Whenever I've bled the coolant I always use a jumper wire at the IC pump relay in the trunk to help bleed, and that's a great way to check and make sure the pump is actually working.

If you've done that, next step is to have the ECM scanned with a STAR unit, standard OBD2 readers won't pull codes until they've triggered a CEL but you'd be surprised what codes may be pending in the ECM that you don't know about. Supercharger magnet faults etc that could contribute to your issue.

 

Thanks for the reply @kevm14

Where do i go from here then? I'm sure there must be a ton of reasons why. I'm mechanically inclined (somewhat) to get this issue resolved. I NEED to feel that supercharger! As i've already changed a bunch of parts, there's a lot that can be ruled out from those areas?

 

@GinDistiller Yes, IC pump was bled by jumping the terminals at the rear fuse box. Working, and bled no issue's... multiple times.
I haven't checked the fuses, these cars are new to me. (Im a VW guy) but love Merc's too.

So with fuses at least, where would I start? and how best to test them?
If the fuse's are all good, i guess the next step you would recommend is a stealership visit?

 

Check your pending codes with an OBD-II reader. I'd think any generic code reader could handle a P code, and that includes pending ones. They just won't talk to any other module, just the ECM.

 

Just looking at them, I think there are a couple of 15a ones that can possibly contribute to poor running. Basically, you've got the engine bay one back by the drivers side firewall, the one on the side of the dashboard on the drivers side (pop the triangle-ish cover off with a screwdriver to access), and the trunk fusebox.

You could take the extra time to remove and inspect them all, but I usually just run a flashlight over them to see the fuse bridges and make sure they all look ok. It's probably a longshot to think a fuse could be causes this, but I have heard of people that this has happened too, so it's worth checking.

Yes, next step is probably a stealership visit unfortunately, or if you're planning to keep the car long term and do a lot of maintenance maybe see if you can find a STAR setup yourself. If you can snag a used one, or Chinese one from a seller with good ratings, it may cost the same as having the dealer run a few hours of diagnostics. It definitely helps though having it stock as some dealers won't want to diagnose problems with modified cars.

Where are you located? You could also get lucky with a forum member or local MB group finding someone who has STAR and at least get you a code readout.

 

Oh actually I take that back a little, kevm14's comment on OBD readers made me remember I have an iCarsoft MBII, they aren't too expensive on Amazon and can access the ECM separately outside of a generic scan. If there are codes you may not get the same readout and detail as a proper STAR setup, but you may get lucky and find something obvious. They are handy to have and can read TCM and other units too.

 

Yes. The MB-II isn't that expensive (I also have one) and it will theoretically read all modules (except mine doesn't seem to talk to the TPMS module for some reason but not positive the issue is the scan tool).

 

@GinDistiller I did purchase on a plan to keep it, but even if i choose not to, i still want to work out all the faults as I dont like my car's not operating as they should. As this has been bugging me for sometime, as it runs fine! just wasnt as quick as i expected it to be.
Im located in Fresno, California. Happy to travel around for a bit of help and networking in a community is always a good thing.

I'll start off with a fuse check with the multimeter, I'll report back to you guys with results and I'll get the car scanned at a shop.

 

There isn't too much connected with the supercharger that directly keeps the clutch from engaging. This should give you a general idea of where to start. I would check the magnetic clutch is actually plugged in, and that your charge air temperature sensor is working, and/or plugged in. You might want to consider replacing that sensor regardless. It's cheap, and they make a major difference in performance if it's never been changed, and it's a ten minute job because of it's easy location.