SLK32AMG Intermittant power loss

[Matt32AMG]

Okay, I’m getting intermittent power loss when I stamp on the loud pedal.
Under normal use or loading, the car is just fine, however as soon as you accelerate hard, sometimes the supercharger kicks in as expected, but sometimes it doesn’t. A classic SC intercooler water pump failure problem goes up the cry! The trouble is, I had that issue a while back and had it replaced, (this was at around 24,000 miles or 18 months ago).
The main dealer, who have currently got my car, half expected that the water pump had failed again too, but apparently this time it’s not. They say it’s the Supercharger fuse that has blown. Or to be exact, the fuse for the supercharger intercooler pump that has blown. This they replaced, where upon it immediately blew again. They replaced it a second time but on this occasion it didn’t blow! fantastic, except, they haven’t as yet found the cause for the fuse to blow in the first instance.

Anyone else had this problem?? Had it resolved satisfactorily? What was the root cause?
Kind regards
Matt

 

[jaymanek]

must be a wiring issue somewhere...

 

[Dieselman]

That is the same pump you had replaced before. It's possibly worn out again and took the fuse out this time but then worked ok after movement or something.

 

[BlackC55]

seconded

 

[Bobby Dazzler]

They don't last long. Have you got to pay, or is it under warranty?

I think I'd be considering a Johnson pump or Ford Lightning pump from the US, and maybe asking an independent specialist in your area to swap it over.

Maybe the guy in the post above this one could help?!

 

[Matt32AMG]

They don't last long. Have you got to pay, or is it under warranty?

I think I'd be considering a Johnson pump or Ford Lightning pump from the US, and maybe asking an independent specialist in your area to swap it over.

Maybe the guy in the post above this one could help?!

Dunno if I've gotta pay yet Rob, though I have sneaky suspicion I might just get slotted for this, as the service manager is already making noises along the lines of it's not the pump but the fuse. I’ll be pretty hacked off if I end up paying £300 for bloody fuse fix
Have you had your pump swapped for a Johnson equivalent?

I may go look up BlackC55 as he's only up the road from me if I have no joy, no offense to Jaymanek, it's just that hes a bit nearer

 

[Matt32AMG]

That is the same pump you had replaced before. It's possibly worn out again and took the fuse out this time but then worked ok after movement or something.

Yup you're not wrong, and I have flagged that exact point to the MB Dealership, as it's a carbon copy of the symptoms I was having before I had the pump replaced 18 months ago. When they replaced the pump, problem solved.

 

[Matt32AMG]

must be a wiring issue somewhere...

That’s what the dealership are saying, except there doesn't seem to be anything flagged as such via the diagnostic test they've run so far. That being the case I said I wasn't going to pay for a weeks worth of finger in the air guess work.

Surely if it’s an electrical issue, wouldn't the fault be logged as a code somewhere in the ECU, e.g. bad earth short or whatever in the circuit in question

 

[Dieselman]

Surely if it’s an electrical issue, wouldn't the fault be logged as a code somewhere in the ECU, e.g. bad earth short or whatever in the circuit in question

No, it would blow the fuse if the live supply was shorted to Gnd.

Not hard to test for, a quick continuity check from the fuse holder to Gnd would show if there was a short.

I still think it's the motor brushes worn down.

 

[Matt32AMG]

No, it would blow the fuse if the live supply was shorted to Gnd.

Not hard to test for, a quick continuity check from the fuse holder to Gnd would show if there was a short.

I still think it's the motor brushes worn down.

OK, I'll push for it being worn bushes given what you are saying has been tried and see what gives. Obviously if it is as you say then it should be a warranty repair.It's also worth noting that I had a quick look in the service history and the pump in question was replaced 5/03/07 less than 7,500miles ago

 

[Dieselman]

Hmm, seems less likely then.

 

[Bazzle]

Ask on here http://www.benzworld.org/forums/r170-slk-class/

A few had the same issue.

Bazzle

 

[jaymanek]

My guess, and it is a guess is that you have some exposed or bad wire somewhere... when they replaced the pump before they disturbed the wire and so it was fine for a while..now its shorting again.

Star Diagnostics will not necessarily show a bad wire... it can if you know what you are looking for, but it will not throw up a fault automatically..

 

[Matt32AMG]

SLK32AMG Intermittant power loss

Quick Update
Got the car back but after two days being with the dealership. They can’t trace the problem and the car has been on extensive road tests without blowing any fuses or repeating the issues I was having prior to taking it in. They say they have checked all the connections and fitment of the Intercooler pump thoroughly. All they suggest is drive it and if it fails again bring it in.

Though kinda irritating that the problem hasn’t been diagnosed or solution found, MB Poole haven’t charged me a dime. So Kudos to them for that. And , since getting it back it drives like a different car, engine response wise that is. Watch this space.

 

[nickwilcock]

I took my car to the dealer yesterday, after having experienced the usual SLK32 AMG power loss and told them that I suspected the intercooler water pump.

They found that the electrical connection to the pump was faulty, so repaired that. But the pump didn't then run until they 'gave it a tap'....

From then on it's been fine; however, they're going to change the pump anyway next week when a new one arrives from Germany.

Fortunately my car is on a MB Tier 1 extended warranty, so it won't cost me anything.

However, with so many reported IC pump failures in SLK32 AMG and C32 AMG vehicles, why hasn't MB raised a Technical Service Bulletin to check/inspect/repair/replace the pumps at the first available servicing opportunity.

I pulled out to pass a truck, put my foot down and the engine didn't respond correctly, so I had to brake and pull back in. That is very dangerous and MB need to recognise the fact before their pump failures kill someone.

 

[nickwilcock]

'Next week' turned out to be somewhat optimistic. Nevertheless, the pump was changed yesterday - despite the previous 'fix', there were additional 'Intake temperature high' events recorded on the EMU and I thought I detected a supercharger shutdown the other day.....

Hopefully all will now be OK - but I'm still surprised that there is no M-B Technical Service Bulletin for this well-known fault.

Both the SLK32 AMG and C32 AMG models have this intercooler pump issue - so why on earth isn't there an 'check, inspect, replace' requirement for these models at the next scheduled servicing opportunity?

Maybe so many owners of these cars drive them so gently that they are unaware that the intercooler pump has shut down the supercharger?