trabots

I found where the fuse/relay is supposed to be under the driver's (rh drive) side rear interior compartment false floor. Which ones are for the intercooler pump? My fuse guide from the tool roll had been soaked at some time so unusable. Cheers.

I noticed the intercooler pump was not flowing water when I took the cap off my split tank. Upon checking, I have no power to my Peirberg 50 pump when the engine is running. It was installed with a resister to keep the pump constantly on. It has run fine for 6 months. I was having a hiccup issue which Jerry suggested a reload of the tune file might fix. Even though it loaded with a message about some "packets" may have been missed, Jerry assures me that as the car started ok the tune would be 100%.

Am I chasing the right things? I did put a voltmeter on the IC pump connector with the engine running and got no volts. Am I right in assuming that if the fuse/relay is ok then the ECU must not be turning on the power to the pump? Cheers again.

knowbenz

Is it programed to be on all the time or it has been rewired to be on all the time?

trabots

Yes it has been running 100% duty cycle for 6 months since install. I placed a resister on the signal wire as recommended and pin 2 left unconnected as per this diagram.

latemodel21

The normal drive for the IC pump is not 100% ... though it can seem to nearly be. If you car has truly been 100% for the past 6months, then someone has changed something. This is important as you are troubleshooting this system which may no longer follow the factory configuration.

Below I have attached the factory wiring for M44 (IC Pump) and its fuse location.

There are various strategies for running the pump all of the time (it is possible it has been changed in programming) ... however, worth pointing out, if your pump has been running 100%, it is likely that its relay is no longer controlled by the ECU, but instead circuit 15 (hot when engine is running). I mention this as you may need to inspect this system both backwards and forwards (from the pump backward ... and from the ecu forward) until you know if/how it has been modified.

The connection at the ECU is shown next to the pump in the first attachment (N3/10, connector 4, pin 34). This output is "active low" (provides ground required to turn on pump relay).


on a related note (for those, who are running the CWA-50 or CWA-100), the resistor on the pump was speculatively included on the signal line as a current limiter, but has proven to be optional (as Mercedes wires that pin directly with resistor omitted on newer models that come equipped with peirberg IC pumps of the same design).


Hope this helps,
Chris

trabots

I accessed those fuses you show and while I did not know which one, they were all ok. I loaded another tune that Jerry had sent me and the pump started working as soon as the key was in position 2, and the engine was stone cold. This was how it has been from the very first tune from EC. Jerry is mystified as he says his tunes only turn on the pump after 900rpm then leaves it on. This car was bone stock, ex-lease with 60k km only. I have found no mods anywhere except that there are a couple of piggyback fuse holders in the engine compartment fuse box for which I don't know the purpose. I suppose I will just have to run it until I get a problem again.

latemodel21

Glad to hear it is working again. Curious that it runs when the engine is below 900 (does suggest a second work-around is in play as Jerry knows his stuff). Of course this may be one of those things that makes more sense to troubleshoot if and when it ever stops working again (since worst-case, it wont leave you stranded, just boost-free for a bit).

If you felt like troubleshooting it further, it would tell you a bit to isolate the ecu output (cut the wire) and then monitor it while you turn on the key ... and then when you pass 900 RPM (should toggle from Vbat to 0vdc when active). You could monitor it without clipping the wire, but that will give you confusing results in the odd case where someone has tapped-on an external pull-down circuit (controlled by circuit 15). Feel free to drop me a note if you want to explore this further.

Cheers,
Chris

trabots

Thanks again mate. I have attached pics of both fuse boxes. I see nothing amiss where the IC pump fuses are. However in the engine compartment you can see a couple of piggy back fuse holders. I was hoping that you might know what they are there for. Cheers.

knowbenz

Follow the extra wires. Any other aftermarket components on the car?

latemodel21

IT is hard to tell what the added fuses are doing without tracing them as knowbenz suggested.

The rearward (forward if this were left hand drive) added add-a-fuse is plugged into F21 (circiut 15r, hot in key pos 1,2 and start).
it should be noted that this is plugged-in in such a way that it draws power through F21 rather than directly from the 15r bus ... unfortunately in order to correct this you would have rotate the fuse holder (180 degrees as viewed from above) which would make it hard to close the box up. SO if F21 blows one day (instrument cluster switched power) it may be as a result of the combined load of the cluster AND the added circuit. I have modified/reconfigured these add-on fuse holders for similar locations to have the added fuse draw directly from the power bus (see pic, this one is in an adjacent circuit15 location) but some will argue it is not worth the bother.

The forward add-a-fuse is plugged into F8 (circuit 30 , always hot). This fuse holder is normally vacant, so the orientation of the add-a-fuse is inconsequential.

I just re-read where you mentioned that your pump comes on in position 2, so these added fuses are probably not related to that.


Curios to hear what you find at the other end of the wire(s)


Cheers,
Chris

latemodel21

looking at one of your photos ... it looks like you have some sort of aftermarket tracker add-on. (indicated in red)

Cheers,
Chris

trabots

Thanks again, I thought it was a tracker. A lot of vehicles here get a GPS tracker installed for cheaper insurance rates. I still need to see why IC pump is on at key on. I am going to unplug the extra fuses and see if the pump is now just wired straight thru one of these fuses.

I had a 1st look at my box of bits including the cats which were removed. To my amazement the 'primary cats' were totally empty of cat matrix, just empty cans. I presume this is not stock. If so it will confirm the previous owner was chasing performance and had wired the IC pump for key on operation. Why could he not have just run a wire from one of those piggy back fuses which powers on key to the pump? It still however does not explain why a change of tune restored the power to the pump.

latemodel21

"I am going to unplug the extra fuses and see if the pump is now just wired straight thru one of these fuses" unlikely as both of the add-a-fuses appear to have 5 amp fuses which is what the cwa-50 pulls at start up AND, the fuse in position F21 is on 15r which is hot in 1,2,and start (you said pump comes on in pos 2) ALSO, the fuse in location F8 is circuit 30 so it is hot ALL the time. I attached a marked up copy of your picture showing where your add-a-fuse is and where it would need to be if it were the power source for your pump (and it would have to be fused at 7.5 or 10 amps). It posible that the fuse at location F8 could be used to power a relay that is triggered by circuit 15 and in turn power the IC pump (but it is under-fused at 5amps, so not likely).

One easy thing to check is to remove the factory IC pump fuse ... if the pump still runs this confirms it has been re-wired .... if it does not run, the test is NOT conlusive (as there may be a rewire done that taps into the factory drive circuit ... not unlikely at all).

otherwise, I would go back to my previous post and trace the circuit backwards and forwards to find any deviation.


I have seen cats disintegrate, but more often then not they leave BIG chunks further down (which tend to clog things up) or rotate/shift in their case (which can make a major clog). I have never heard of "dual immaculate disintegration" of cats ... so I would assume it was a performance mod (they should call this the "california tune up" : )

Cheers,
Chris

trabots

Just like your pic Chris, the location for the IC pump fuse is devoid of a fuse. So confirmation that the pump is being powered from somewhere else and that this car has been hot rodded. What I cannot understand is the lack of evidence that the primary cats had been cut out to remove the cat material. I suppose the cat material could have been broken up through the manifold flange if the exhaust had been removed from the manifolds. I will now try and trace where the wiring from the IC pump leads to.

latemodel21

Removing the exhaust (except manifolds) and then busting up the cat(s) from the manifold side as you suggest and then pouring pieces out manifold side is the likely method.

One place to look at for your IC pump investigation is its drive relay. Mounted direct below F51, relay "R" is normally triggered (active low) by the ECU. If someone were to create a work-around, a simple way would have been to remove relay "R" and plug a wire (hot when key is in position 2 and fused at 7.5 amps) into the spot where terminal 87 of the relay was (this is the relay output that is wired directly to the hot side of the IC pump) . Look here for added wiring both on the front and back side.

I have marked up a pic to show where relay R is/was and which pin was terminal 87.

hope that helps,
Chris

latemodel21

Well, I just noticed that there is a second wiring set up for 2006 (05-2005 build and newer). It was not shown clearly in the rear sam diagram, so I missed it .... until I happened to stumble on a diagram for ECU connections (that was specific to 2006 on).

sorry for the confusion ...


instead of using F51 and relay "R" like 2003 through 2005,

your car likely uses F60 and relay K60

attached are a couple of pics.

looking at the first pic (wiring diagram) ....
while the fuse (F60) (which goes to K60 pin 8) is hot all the time (circuit 30), it is not clear as to the power that is on pin 6 of the K60 (in turn coming from K40/5). If K60 pin 6 is sourced directly from circuit 15 (hot in position 2 and start) then shorting the relay drive (K60 pin4) to ground would make your pump run anytime you are in key position 2.
so, you can check to see if pin 4 of the K60 connection has be changed so that it goes to ground (instead of to the ECU as it was originally wired) and check to see if pin 6 of the K60 is (or was and still is) tied to circuit 15 (does it read 12vdc in key position 2?).


hope this helps,
Chris

trabots

Sure did help Chris. I wondered why your first pic didn't have those stacked relays. Still, with this tune my pump turns on and with the previous tune it did for 9 months and then stopped turning on the pump. Both Jerry's tunes. This may take awhile as the urgency is gone. My car works so other things might be priorities.

As my car is going into the muffler shop to get a custom muffler installed where the secondary cats were, I now want to cut open the empty primary cat cans, install a couple of baffles, weld them back together and re-install them.

latemodel21

Glad that helped, when you get to checking this out, you may find most of your answers by probing the connections at your K60 relay.

The pictures of the rear SAMs I posted earlier in the thread are all from the Mercedes web based Electrical Troubleshooting Manual (ETM), I suspect the first (early) rear sam pic was a non SC R230 (SL500). My rear SAM (pic attached) is more populated and has a relay in the K60 position, but not one above it (guessing they added K60 in 2006 bumping up existing relay one position) which is why your pic did not look foreign to me.

I am confused as to what you are planning on doing with your hollow front cats ... are you planning on reinstalling them to make your car more "inspectable"? if so, wouldn't a nice piece of tubing be a better choice than baffles?

Cheers,
Chris

trabots

Chris, I have 3 inch straight pipes with cross-over from shorty headers back to both of the stock resonators. The car is fine at idle and cruise but sounds like an AA dragster when having fun and is quite annoyingly harsh with top down. I want a bit of stealth when having fun and those factory cans don't silence near enough. The cats did most of the silencing. I am cutting 2 full ID steel discs with an offset 3 inch hole in each. They will then be welded into the cut in half cat cans, with the holes offset 180 deg and offset as much as possible with the inlet and outlet. There should be no back pressure and the baffles should hopefully have some of the sound energy just bouncing around in the cans and cancelling some of it. As it is going in to have a custom center muffler installed, I may as well have these put back on. While I am not really worried here in Oz, they will as a bonus give the appearance of cats as you say, just in case I get a nasty cop who gives me an inspection ticket. I did something similar to a 575 F car I had and that configuration does drop the noise a bit.

latemodel21

Sounds like you have put a lot of thought into this. I hope you get a result you are hoping for. When I was a kid, my 65 GTO only had headers with blown out (empty) glass packs ... I got pulled over a lot : ) Nowadays I try to fly a little under the radar. Hope yours ends up loud enough to enjoy, but not so loud that can't stomp on it wherever you want to : )

Cheers,
Chris

sound 8

You missed it !!!!!!!

earl3

Quick bump to this thread for those that found this through various search engines. First, thank you to trabots and latemodel21 for the info and digging.

I have an 09 SL65 that I was looking to setup with the IC pump running in key pos 2. The mod was quite simple. The IC pump relay for the 09 does indeed live behind/underneath the passenger seat storage bin as shown in the above pic, but the IC pump relay was the one on top of the vertical stack of the two relays shown in latemodel21's post. The purple/red wire going into the "30" terminal on the top relay was the dead giveaway.

The "#6" input to the relay (from latemodel21's post #15) becomes hot with the key in position 2. Grounding the relay blade (#4 in the same diagram, nearest the front of the car -there's an 8mm screw just underneath the relay area which suits perfectly for the ground) and voila, IC pump runs w/ key in pos 2.

I'll attach pics and start a build thread for my car shortly but this mod helps stay ahead of IAT creep (approx 15-20 deg F reduction in general) and lets the pump run all the time the car is on or the key is in pos 2. Not bad for a 20 minute mod!

Thanks again gents!