E55 AMG SC No Boost after 40sec from cold start

[AngeloSebaaly]

Hey Guys i got a nasty problem with my E55 engine that no one can figure out,
The engine is equiped with Supercharger Pulley kit no Clutch direct pulley with a resistor on the clutch plug .
The problem is:
-On cold start the first time u start the engine when its cold u have about 30 to 50 seconds of full boost 14PSI the crazy power to the wheels ,
-After 30-50 sec the boost is gone and the gauge reads 0 PSI and the power is gone
-Turning the car off and on dosent do anything
-Resetig ecu didint work
-swaping ecu didint work
-Changing Supercharger Bypass valve didint work
-changed all the hoses around the supercharge
-done a boost leak test no leaks
-The car will not get boost untill it is dead cold sitting for a while then it will also disapear after 30-50 seconds
-Ecu has zero faults even the swaped one didint give any faults

Anyone ever faced this issue :/ ? i cant find anything related to it :/

Also we removed the supercharger and it was inspected for worn blades or bad bearings and such nothing checked out everything looked brand new :/

The engine has 50k miles only on it its like almost new

Any help is much appreciated

 

[Gbrowncls55]

Very strange....belt slip perhaps if you have fitted a smaller fixed pulley but not used a shorter belt (dont know what size your pulley is). From what you say the ecu cannot cut off the SC with a fixed pulley but could still pull timing if IATs get high, in which case it could I suppose be a failed IC pump, but I guess thats all been checked?

 

[Alex]

Tried changing your MAP sensor? Also what does Star say?

 

[AngeloSebaaly]

The pulley is a 1.2k kit that comes with both pulleys belt arp bolts and everything related,

Mechanics thought that it might be the cooling system so they seperated it and made a circuit for the sc and a circuit for the car still nothing they even upgraded the pump

Map sensor was replaced air temp sensor was changed as well

And nothing no faults detected they even different scaner types no faults at all

And i keep thinking my pulley is always running so the ecu has no control what so ever for boost mechanically speaking as long as the engine is running i should always have boost once the pedal is pressed i am thinking could they have missed somthing regarding the Supercharger any symptoms that could cz it to lose boost totaly :/ ?

 

[Gbrowncls55]

Rather puzzled by this. You are sure its a fixed pulley. If so as you say the sc will be working at all times and the ecu cannot dissengage it as it would normally. So if the sc is producing the boost it must be being lost somewhere after the supercharger. Faulty new bypass va!ve or a badly cracked pipe on the intake side that only opens up when it gets hot (very quickly with an sc). Had something similar on the intake on an Audi Ur quattro some years ago. As said above get it on STAR and get fault codes read. Much better than guessing.

 

[AngeloSebaaly]

Thats what i am saying we already put it many times on Star on the old ecu and the swaped one no faults related we only got
B4/3 Fuel Tank Pressure sensor ,

also sitting with the guys yesterday trying to figure out what might be changing so we thought maybe it could be the Idle air control valve making it boost while cold and once its dont its job the car is diying because we tried to turn off the car and wait for 2 hours and start it again we managed to see boost up to 10 psi revving the engine stationary .

anyone got an idea how is the idle system on this car ? could it be related or are we thinking wrong

 

[Alex]

When you say boost, I assume you mean the supercharger boost and not atmospheric pressure? By design the bypass valve is routing all the air to the engine for drivability and emmissions at low speeds. The TB shouldn't open until after about 3k rpm. This is when the s/c kicks in as well.

By spinning the s/c constantly with the TB flap closed, where is it getting its air from?

 

[AngeloSebaaly]

The Kit is similar to this one with all the parts , and yes boost i mean the supercharger boost also u can see the bypass valve open and close just when u hit the throttle the mechanics says its working properly and they monitored both the old and the new one on Star both give the same readings that there working

these are the pictures of the pulleys and engine as u can see its barely used :/

 

[Alex]

I was talking about the TB as in your throttle body, not the bypass valve. When you rev the engine up, does the TB stay closed?

 

[AngeloSebaaly]

The throttle body opens up and the bypass valve closes

 

[Alex]

Sorry, I realised the original design of the inlet manifold is different to what I'm used to. Yes, your TB works all the time to allow the air in.

The problem could be with the ECU and the fact that some of the air at idle gets sucked in by the blower instead of going straight through the bypass and in to the engine.

Weistec have managed to work around the idle issue as their supercharger is engaged 100% of the time and uses the original bypass design. Maybe they can help?

 

[AngeloSebaaly]

Any idea what they do or how they did it or how to test if it is the idle valve? because im on not from the UK i just come here for the info usually always UK falks have the best data and knoweledge by my experience over the years

 

[AngeloSebaaly]

Anyone else can shed a light on this issue could it realy be the idle control valve?

 

[AngeloSebaaly]

New Update Today we tried somthing we removed the iat sensor and placed it outside in a glass jar so it thinks its cold the whole time to see what hapens ,

And surprizingly we have boost and the car has crazy power So what do u think is hapening once it thinks its warm :/ ?
what could be happening as i also noticed that there is no idle valve control i think the ecu controls the gas paddle for idle ?

 

[Mr Kripling]

I assume you did the first thing at the top of any M113 supercharger cut out check list and made sure the intercooler pump is still working?

Nvm, just read your posts more carefully. When you say they upgraded the pump, did they use the revised Bosch part or a Johnson one?

 

[Vilus]

The ECU relies on readings from all the sensors. The main three being Intake Air, Charge Air and Ambient Sensor located near the front foglights. If any one of them is not reading right, then the engine management program will not function correctly.

 

[AngeloSebaaly]

All three of those were changed

 

[Gbrowncls55]

Have you logged/checked the live iats from cold to loss of power. Could be a faulty iat sensor or some other problem with cooling leading to actual high temps or mal sensor high temps causing maximum timing pull. If its a fixed pulley I can't see how the sc can simply stop as its always turning.

 

[AngeloSebaaly]

yes thats my point why would the boost disapear x.x like it has no option but to keep boosting unless its escaping from somewhere like the bypass valve , in that case what makes the bypass open what scenarios is it knock ? low fuel ? high temps ? what is the actual thing that makes it open if it infact it does open?

 

[Gbrowncls55]

Have you logged live iats whilst driving from cold to loss of power? You said yes but I think you were referring to something else. Where are you getting your boost readings from obd or do you have a separate gauge/sensor