M5CLK

For some strange reason, my '02 C32 is limited to 100mph (160km/h)... There's no malfunction code and winter tire speed limit is set to off. I just noticed it a few days ago and I've tested it a few times now, hard blast from 80km/h and when I hit 150km/h-ish, it felt a surge then fuel cut and gears stayed in I believe 3rd at 6k rpm? Pushing gas panel further does nothing at this point, it felt exactly like a limiter...

The gearbox runs fine at normal speed and I do have 4th gear and OD during normal driving, anyone know what could be wrong? Is there any other settings that only Star Diag could pick up??

GatorLCA

It's your HE pump. When you get above 3k RPM (~100mph) the supercharger is always engaged so if you're pump isn't flowing coolant it won't allow the supercharger to cool down therefore the SC gets hot. When stuff gets too hot it breaks so the car shut it down

That surge isn't the fuel being cut, but rather the supercharger disengaging so you then feel the power loss. A lot of C32/SRT-6 owners have delt with this lately.

edtv82

i think its governed at 155mph

M5CLK

Thanks for the reply, that makes sense.. Is there any other method to test the HE pump? Coz. at 100mph, even with the SC shutted off, shouldn't the car still shifts into 4th? In my case, it just stays at 3rd 6,000+rpm even if I push it harder, and no speed gain...

shanusanus

Defo Supercharger pump - this happened to me - same thing. Got replaced under warrenty. Apparently the pump only lasts 40K miles or so. mine went at 56K miles.

M5CLK

Thanks guys... I've reading a bit and looks like I can nail it down to IC pump, HE water pump or SC pump? My car's out of warranty and I'm getting ready to sale it for the C63 later on this year, but need to get it fixed beforehand I guess.. What are the syndrome for them? Is there anyway I can test to make sure which it is coz obviously, the shop I go to will NOT take it to 100mph to test, and I just can't replace them one by one and hope for the best Thanks!!

turbo16lbs

You dont need to go 100mph to test this theory. Just take it to 3k RPM cruising.

M5CLK

Everything is fine as long as it's below 100mph, traffic light hard launch to redline and everything.. My problem is sudden lost of power right at 100mph And I just did another test just now, hard pulling to 180km/h (112mph) right after warmup without any problem and it was still pulling strong at 180km/h, so I guess it's definately heat related since the previous tests were all performed after the car has been running for a long while.

Can I eliminate SC pump then since at cooler temp right after warmup everything is fine?

ChicagoX

It's an intermittent pump failure that will shortly become permanent.

Fix the pump, be happy-it's cheap.

M5CLK

Errr.. Which pump are you talking about? :P The SC pump?

m3_eater

This is all you need to know:

https://mbworld.org/forums/c32-amg-c55-amg-w203/146457-1fastc32-s-cheep-intercooler-pump-replacement.html

Detailed instructions, with pictures. Enjoy!

M5CLK

Thanks for all the input guys. Please bare with me, but I just want to make sure I understand the problem.. Should my problem be the SC pump or IC pump, shouldn't I lost the SC totally? I meant, I'm only having problem getting past 100mph, if I slow down and go again, I still have full SC till up to 100mph... I understand it could be an intermittent problem, but then I won't see the problem again until I hit 100mph everytime.. Does that sound right?

BARRATT

buy the Johnson pump from LET and be done with it.

FrankW

they're one and the same. there's only one pump that would fail on the cooling end.

c32AMG-DTM

You know, I'm going to go out on a limb here and say I'm not 100% sure that this is the IC pump failure, while everyone else is dismissing it as such. Here's why:

1. IC pump failure can be intermittent - but once engine is up in the normal operating temp range, IC pump-related power loss can occur at ANY speed and ANY rpm, assuming a load level that would normally engage the S/C. OP doesn't display this symptom... in fact, he directly states he always has full power right up until hitting 100 mph, at which point it's exactly like hitting a speed limiter.

2. The fact that he's experiencing tranny-related issues as well - i.e. tranny won't shift out of 3rd gear. IC pump failure should be completely independent of tranny shift-points and speeds, shouldn't it?

Anyway, I agree w/ others, replace your pump since it's cheap and easy, and good preventative maintenance anyway - I'm just not 100% sure this is definitely going to fix your problem, however. Keep us posted

M5CLK

Forgot to mention, on the last test which was right after the warmup, I also reset the ECU prior to the test. Maybe that fixed the shifting out of 3rd issue?? Hmm... Anyway, thanks guys, I'll replace the SC pump and do more testing to see what happens.