Vadim @ evosport

FYI:

Over the last several months I have noticed our C32 varying greatly in power from day to day. Several times DME shut-off the compressor. After scanning for trouble codes nothing would come up. Finally I left the scanner hooked up for several days until power went down again.

Intake air charge temperature (IAT)was going over 200F, in light driving. I pulled to side checked fluid level, it was OK. Checked to see if fluid was running through intercooler lines and found that there was no pressure. Turned the car off and turned back on, IAT went down to normal. Pump was back on.

Over the next several days pump would intermittently shut of for several minutes, only to come back on again. Finally it died completely.

Over the years I have heard some rumors about pumps' reliability. On MY03 and up, instead of having pump run all the time it only comes on under boost.

Intermittent nature of pump's failure might explain why there is some variance from car to car.

We are looking into using larger, higher capacity pump. Meanwhile an air intake temperature gauge sounds like a wise investment.

SiLvaC32

hmm... that sounds weird, what can we do about that? if we take it to the dealer, they'll probably say it is caused by the mods that i have done.

m444

What is the normal air intake temperature?

Does the stock IAT sensor operate as a variable resistor, with two leads or is it more complex? One might be able to tap into the stock IAT, to measure the voltage with a window comparator and LED readout, red bad, green good, yellow marginal.

Vadim @ evosport

Silva: Pump failure is a known problem. I have been talking to my sources and they confirm it.

m444: Stock air temp sensor is 0-5V, so it could be used to display air temp.

Normal temps are 20-30F above ambient under cruise and 70-90F under full boost.

m444

So one just needs to make temp and voltage measurements to map the temperature to the voltage. Then we can have a create voltage driven temp gauge.

So there were no MB faults or fault codes when the pump failed? That's pretty sad.

Vadim @ evosport

You could make a gauge out of temp sensor or use a portable Palm-based scanner to monitor the temps.

Sadly there are no codes for pump failure.

Zeppelin

Does this mean that the intercooler is heat soaked with 210 plus degree water until boost is applied. It must take several seconds for the intercooler to cool down. This must make for some poor power due too the hot IAT during that few couple of seconds.

Vadim @ evosport

IAT will go as high as 255, that's when DME shuts-off the compressor. With compressor off IAT is around 185-210F. At 190F DME turns the compressor back on again and then within 2-3 minutes it is back up to 255F.

Obviously one can feel it as the car jerks when compressor comes in and out.

m444

When the IC pump dies, does it blow a fuse or just open up.

Vadim @ evosport

Just dies. IAT goes high, compressor shuts off and on and there are no DME codes.

Zeppelin

Vadim,

Also good to know stuff above, but I was thinking along the lines of a perfectly working MY03 and up intercooler circuit. If the intercooler pump does not run continuosly then the intercooler must heat soak since the water is not moving through it. Won't this cause tip in performance issues?

Vadim @ evosport

Logically - yes.

I have not scanned 03MY extensively to track IAT. Test driving them I have not noticed any tip-in issues.

m444

The intercooler pump should be on thermostatic control - turn on at some temp (130F?) and off at some temp (120F?). There needs to be some reasonable hysteresis in this temp control function, to keep it from oscillating.

Vadim @ evosport

No. Even at part throttle compressor adds heat, so ideally you want to start as cold as possible when boost comes up.

I just got a new bigger pump (30% more flow). I will try it next before any other mods, as I am getting more calls about pump failures in Europe and Asia. Also on SC55 engines.

stephens

Vadim
Any updates on the pump, what part are you using?

m444

Where is the radiator for the a/w IC located?

Is it at the bottom, in front of the A/C radiator?

The P/S radiator is mouted at the top, diagonally.

Also, which company scan software are you using with the Palm, Autotap?

Prasith32

Vadim,

i had the same problem as well. My IC pump failed and no error codes were thrown. However when you rev the car it feels like a c230 and just revs up high with no supercharger engagement. The dealer also told me that it is linked to the throttle actuator and the programming causes the IC pump to fail. There is a new and updated part that was replaced and I haven't had the problem again.

Prasith

Vadim @ evosport

Stephens: New pump will be installed shortly, I will provide more details once we are ready.

m444: Stock IC radiator is located right in front. If you look at the car you will not miss it. The pump is located on the passender side right below the front bumper.

We are using Nology Palm-based scanning software.

prasith32: Since I posted about the pump I received a lot of calls and messages from other 32 and 55 owners who had this problem. You are right, new pump has been updated.

stephens

Vadim
I have all the schematics for the cooling and electronics for the SC systems on the AMG if you are interested. More than happy to share info with you to achieve a mutually beneficial result.
I have discovered the Bosch pump used on the AMG V8 cars is the highest rating by a fair margin in both pressure and flow than anything I can find in the aftermarket ( link to Bosch pump specs ), so solutions must revolve around increasing the cooling system capacity.
As an example on the E55 only a single small low temp radiator is used. On the W220 S class the small low temp radiator is merely an adjunct to a full size low temp radiator.
See diagram

Vadim @ evosport

Stephens: Thanks for the info. Great diagrams. I wonder why AMG did not add an extra IC radiator for W211, but did it on W220. Is it an extra weight of W220 that need it or simply lack of space on W211?

The stock pump flows 27L/min at 0.15 bar restriction. The pump that I am going to try next week has 90L/min at the same restriction. The inlet and outlet are about twice the stock, Bosch diameter. I will post the results.

awiner

Stephens, thanks for the great info ! It is interesting that the W220 and W215 use the additional radiator.

It is also worth noting that the W211, W215, W220 and R230 use the coolant from the normal radiator expansion tank vs the headlight washer tank as I believe the W203 uses (???)

stephens

The CL/SL55 have the large radiator only, without the small one.

awiner

My 2003 CL55 has both. The large and small. 110/10 and 110/11 ...

Wiedermann

Mr awiner:
Headlight washer tank on W203 and/or any other MB is designed to even run empty without causing any effect to the cooling system on any configuration vehicle to date. That reservoir (Headlight washer tank) contains liquid intended for cleaning (windshield and headlamps --for those cars equipped with such feature, and if present the headlamp washers, the reservoir capacity is much greater than those vehicles without it--) purposes only; not cooling.



Wiedermann

awiner

The difference is on the CL and S class the headlight washer tank is heated so the water is really hot.

This is why I'm sure on these vehciles AMG chose to use the coolant resivor to syphon liquid from if needed.