04 E55 AMG: high intake air temps

It's your engine, transmission, driveline
kevm14
Posts: 15201
Joined: Wed Oct 23, 2013 10:28 pm

Re: Mercedes E55 AMG hunt (W211)

Post by kevm14 »

While I was sitting at idle I checked my intake air temps. It was like 160F. It seemed to come down a little if I got on the throttle so maybe the engine bay was just completely heat soaked. But I did some reading and evidently the intake air temp sensors do go bad. So I ordered one from FCP Euro. $41.91, lifetime warranty (per usual).

I will have to try beating on it and monitoring temps. Hopefully it doesn't also need a pump. If it does, this is the one it needs: https://www.fcpeuro.com/products/merced ... 10#reviews

$113.

The main symptoms which I've never had is the supercharger shutting down, which is immediately noticeable. But a skewed temp sensors can cause more subtle issues. I think cruising down the road intake air temps should be like +20F from ambient. Mine was like 160F (again, after MASSIVE heat soak) on an 80F day. Not sure that's right. This car can be even faster? Hilarious.
kevm14
Posts: 15201
Joined: Wed Oct 23, 2013 10:28 pm

04 E55 AMG: high intake air temps

Post by kevm14 »

Went out for another drive. Outside temp is down to 73F. Intake temps were still quite high. Eventually, after driving, the temps don't fall below 150F even when driving at speed and not hammering. That clearly isn't right. I also got it up to 180F on a quick pull though it came down 20F fairly quickly but then stayed high. Since there is no severe performance loss as would be the case with a failed intercooler pump, I think I can conclude that it really does need an intake air temp sensor. Previous owner wouldn't really have known - I think he would have had his shop look into it if it suffered the famous sudden power loss from a failed I/C pump.

When I got home I measured the temp of the top of the intercooler with my temp gun. It was only 5F over ambient. So I am excited. Supposedly smooths the idle (there is some occasional roughness but nothing like my STS with the failed mounts) and I do sometimes notice a tip in hesitation off the line, that is also the mark of a failed AIT sensor (they used AIT in Benz land as opposed to IAT in GM land).

For $40 this will be quite satisfying and I am excited to feel (and measure) the difference. Improving performance and drivability for $40 is nothing to sneeze at.

If the temps still seem high, I will go hammer on it more and see what it does under extremis. If I can get it to shut down the supercharger, I'll do the Bosch 010 pump, which is a direct fit replacement. Not interested in any aftermarket intercooler setups at this time.
kevm14
Posts: 15201
Joined: Wed Oct 23, 2013 10:28 pm

Re: 04 E55 AMG: high intake air temps

Post by kevm14 »

https://mbworld.org/forums/w211-amg/670 ... 5-amg.html

https://mbworld.org/forums/w211-amg/669 ... zilla.html

Oh man, look at these posts. I think this is going to make a noticable difference. Maybe the car will finally scare me a little.
kevm14
Posts: 15201
Joined: Wed Oct 23, 2013 10:28 pm

Re: 04 E55 AMG: high intake air temps

Post by kevm14 »

As I mentioned to Adam at lunch yesterday, this appears to be a speed density fuel injection system. There is no mass airflow sensor. In these systems, especially with forced induction, the intake air temp is CRITICAL to calculate the proper air density and thus total air mass flow. This explains why this car would be more sensitive to sensor issues.
kevm14
Posts: 15201
Joined: Wed Oct 23, 2013 10:28 pm

Re: 04 E55 AMG: high intake air temps

Post by kevm14 »

Did the sensor. It was easy but it didn't fix it. Cleaned the throttle body but it wasn't all that bad.
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I did however find this thread.
https://mbworld.org/forums/w211-amg/615 ... ation.html

It's almost as if I posted this.
Confirmed, it's absolutely bad. 50 degree ambient air temp it slowly climbed and stabilized at 135 degree IAT. Coming back with 60-62 degrees ambient air temp it stabilized at 149 degrees IAT. I had to drive around some idiots and gave it some gas on a short pull and watch it go up to 167 degrees IAT pretty fast. I can only imagine how insane it would get over 100 degrees ambient like it is in the summer.
UPDATE: I replace the pump with a Bosch 010 this morning and woooooow did it make a difference. Air temperature of 60-62 degrees and highway driving the AIT stayed around 75 degrees. I did a pull to 100 MPH and it went up to 82 degrees then took seconds to come back to 75 degrees.

I'll monitor fuel economy and power after warming up and the likes which may not vary a whole lot with the cold air temps, but the pump swap definitely put it back where it should be. I will test the old one (that was a 003) and see if it was not working at all, or just poorly, for reference.
Ordered the Bosch 010 pump from FCP Euro. I think mine is failing but not failed. I wonder if it is an 010 or the older model.

Toward the end of my test drive, I rolled onto the throttle from a very slow roll, uphill slightly, and the traction control light blinked. So it's not like the car is seriously lacking power. I should, however, still pick up some power just from lower intake air temps.
kevm14
Posts: 15201
Joined: Wed Oct 23, 2013 10:28 pm

Re: 04 E55 AMG: high intake air temps

Post by kevm14 »

The pump is a serious problem. I went from a 12.97 @ 107 to a 12.07 @ 114 just changing that. Not even factoring the ET, I gained 7 mph!
Damn. I wonder if I'll have that kind of improvement. That's basically what the difference should be between the STS-V and E55. And as I originally said, it felt closer to the STS-V I drove than a 114 mph trap should feel. We'll see, won't we?

I need to order some coolant actually...
kevm14
Posts: 15201
Joined: Wed Oct 23, 2013 10:28 pm

Re: 04 E55 AMG: high intake air temps

Post by kevm14 »

Looks like it takes the pale yellow G-05 coolant.
https://shop.advanceautoparts.com/p/zer ... Term=Zerex
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kevm14
Posts: 15201
Joined: Wed Oct 23, 2013 10:28 pm

Re: 04 E55 AMG: high intake air temps

Post by kevm14 »

Got my coolant yesterday.

Looks like the Bosch 010 pump comes today also.
kevm14
Posts: 15201
Joined: Wed Oct 23, 2013 10:28 pm

Re: 04 E55 AMG: high intake air temps

Post by kevm14 »

Plot gets a little thicker. I tackled the rats nest of custom wiring the previous owner showed me. It taps off some stuff and then a red wire runs mysteriously down and disappears in the engine bay, sort of like it runs to the intercooler pump. There was a scotch lock on one of the wiper motor wires. So professional.
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I removed everything except the red wire. I tested the resistance and...yeah it's motor resistance. Like under 4 ohms. Touched it to positive and a pump runs. Sure seems like the intercooler pump. So that's interesting. It sounds fine, too but what do I really know...

I also tried jumping the relay in the trunk and that does NOT cause the pump to run. So either the previous owner tried to modify it to run the pump all the time, or this was a "fix" because something broke between the relay and the pump. I hope I can just put it all back to stock and there isn't some underlying wiring issue.

I will say when I plugged the pump relay back in I felt it click so the control side should be working. Hopefully I can just repair the plug under the car if they hacked into that or something. Ugh.

It's on ramps now. I raised the suspension (that's cool) but it wasn't enough. I simply laid a short 2x4 horizontally in front of the ramp, against the tire. That was perfect. The car just drove up onto the wood, which lifted the front end enough to clear the ramp.
kevm14
Posts: 15201
Joined: Wed Oct 23, 2013 10:28 pm

Re: 04 E55 AMG: high intake air temps

Post by kevm14 »

I followed the technique of that video. Added some electrical tape to vice grips as padding to clamp off the coolant hoses. Got the old pump out. It is a Bosch 010 which is the same updated pump that I bought to replace it...

Here's the thing though. Someone did something questionable with the wiring. That wiring that the previous owner showed me was in fact for the intercooler pump. Looks like they picked an ignition switched source and added a relay, and that made it run all the time I'm guessing. I had unhooked some of it so I wonder if my high intake temps were because the pump wasn't actually running at all. I don't see how it could have.

Someone actually cut the positive wire and spliced this garbage in. I pulled all of it out.

Then I reconnected the broken wire and tested it from the trunk. It worked when I jumpered the relay mount pins. Phew!

Soldered, shrink tube, tape. This is good.

So I think all it needed was....restoration of power to it. But now it has a brand new Bosch 010 with a lifetime warranty. So I have that going for me.

Bleeding was alright. I connected my 5/16" ID hose to the nipple, switched the ignition on, jumpered out the relay to force the pump to run, and ran the hose to the pressure tank. I had to pinch off the return as it said in the video to get flow out of the nipple so I did that. Didn't seem to take long to bleed but I must have let it run for 5 minutes just sort of watching it.

Now I am hoping there was no other issue that caused someone to hack that wiring. All I can think of is this was a DIY hack to make the pump run all the time, instead of just whenever the computer asks for it. So assuming that is all working properly, I should be in good shape. Obviously the IATs will tell the story.
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All of the mess I removed. This consisted of wires, a relay and a fuse. Awful! NONE of the wires were soldered, either. Just twisted and taped.
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I guess this car was a little molested. Not too bad I guess if this is the extent of it and nothing causes me issues down the road. I shouldn't speak too soon, I haven't even finished my work or started it...
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