non warp speed SL55

[sl55plymouth]

Hi all
I have a intermittent power problem, car runs really well pulls like a train, I ease off and power up again and very little power, stop switch off and start up again and it happen all over again, feels like the supercharger isn't working, is that possible, I believe the charger switches out after a short time after starting and then cuts back in when you move off.

Is there anywhere I can connect a pressure gauge to read off the boost pressure to see if it is working, don't want to take it to Mercedes to put onto Star, I tried to get an ignition key and they couldn't get that right and at £163 per hour

Or if anyone can come up with another idea I would be very great full.

Ian

 

[AndyPCD]

Sounds like your suffering from the usual common problem that most 55's suffer with.

It sounds like the charge cooler pump is failing

What area are you in we might be able to recommend a local indy to take it to rather than main dealer.

 

[Vilus]

I'm guessing Devon??? Possibly Plymouth......

 

[AndyPCD]

I'm guessing Devon??? Possibly Plymouth......

Didnt even look at the name lol.

 

[Alps]

I think id agree with Andy, time for a new charge cooler pump

 

[sl55plymouth]

Yes its Plymouth Devon :bannana:

I was told this could be the problem, but if I turn the engine off and restart almost immediately it drives as it should until I back off and floor it again its lacking again, almost as if it is resetting something.

 

[Ginger55k]

As your inlet air temperature rises the ECU will disengage the supercharger to safeguard the engine from damage, this then feels like a loss of power till the temperature lowers allowing the supercharger clutch to engage again.

Simple fix on the 55's, the pump needs replacing

 

[W126]

Johnson cm30 pump, I think, is the one to go for I believe.

 

[sl55plymouth]

Johnson cm30 pump, I think, is the one to go for I believe.

Is this a straight swap, or is it one that has to be integrated with the old one.
Is this cooling part of the engine cooling system or is it a separate system ????

Ian

 

[Ginger55k]

Is this a straight swap, or is it one that has to be integrated with the old one.
Is this cooling part of the engine cooling system or is it a separate system ????

Ian

Its separate, well kind off, its difficult to explain simply, it is 2 systems which share a common reservoir, the pump we are talking about cools the air intercooler, in laymans terms, if you compress a gas you generate heat, the supercharger is doing just that by providing more air to the chambers which means more fuel can be added which means when you floor it you laugh your **** off.

Under your bonnet sits a beast of an engine it generates a lot of heat, have a read of my thread on how to cool these monsters.
http://www.mbclub.co.uk/forums/amg-performance-lounge/160285-55k-cooling-upgrade.html

 

[sl55plymouth]

Many thanks Ginger
I am a marine engineer and these pumps are used in marine applications, one of the companies I deal with has these and I can get a good discount.

Do you have to drain all of the coolant or is it just part of it, just wondering if a coolant change at the same time is worth it.

I am going to read and wait till you have yours sorted and then I should have some dosh to upgrade.

 

[Ginger55k]

Mine already has the pump upgrade, the johnson cm30 already mentioned, no need to drain, hose clamps to swap out, you should find on the net DIY fix for this, just make sure its vented and all air purged from the system, probably cost no more than £200 from an indie to do for you, best to find a merc specialist in your area with star diagnostic to fully check this is the cause.

 

[n13]

heres my diy...

 

[sl55plymouth]

Picked up a Johnson CM30 £132 inc VAT
just waiting for the rain to stop.

 

[mars1960]

Hi all
I have a intermittent power problem, car runs really well pulls like a train, I ease off and power up again and very little power, stop switch off and start up again and it happen all over again, feels like the supercharger isn't working, is that possible, I believe the charger switches out after a short time after starting and then cuts back in when you move off.

Is there anywhere I can connect a pressure gauge to read off the boost pressure to see if it is working, don't want to take it to Mercedes to put onto Star, I tried to get an ignition key and they couldn't get that right and at £163 per hour

Or if anyone can come up with another idea I would be very great full.

Ian

Iv'e had this happen, first time it was diagnosed (as previously said) as a charge cooler pump failure.
The second time it happened a few weeks later it was a throttle sensor failure.
Both gave similar symptoms but power loss from the throttle sensor failure was more pronounced, with the pump failure it would rev high but without the expected power.