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Discussion Starter #1
So, I took my GLA45 to Laguna Seca AGAIN and once again had power issues. I was told it was getting heat soaked, so I got an upgraded Heat Exchanger. I have the Weistec W.3 Turbo upgrade, ECU, and DP. It is not hard to get the car to start having this problem when hot and under power. I was having the issue even on warm-up laps not exceeding 80mph. I can easily replicate this just driving on the freeway.

Here is a 6-second video and you can hear the gurgling under power. The air temp outside was 55F. The OBD reader shows no code issues.


 

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Hey Jim

you need to pull a log of that while its happening

I have the bluedriver, and it communicates well, but I have not tried to use it for serious work as yet.

You need to beable to see commanded AFR, KR, ign adv, and WGDC
other stuff to pinpoint, but at least one of those params will be going wonky during your burbles
 

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Discussion Starter #3
Here is the MB dealer test (attached) done yesterday you can see there are 3 Faults.



P13C700 The exhaust flap has an electrical fault or open circuit

P1CE700 Crankcase ventilation in WOT operation (cylinder bank 1 has a malfunction)

P026A00 The efficiency of the charge air cooler is not sufficient
 

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Sorry to hear of having issues.
Agreed, logging is needed to get to root cause.
What is the IAT post turbo? does this validate the 'heat soak' hypothesis? without logging... shrug.
What fuel used? are we seeing knock? hot air = knock = pulled timing.
Might be too aggressive of Wastegate for the setup - ECU calibration.

Also, Heat soaking can also occur on the Intercooler core, not necessarily the heat exchanger. I changed the Intercooler, left the exchangers alone. My testing saw no need for the aux or main heat exchanger core to be changed.
 

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Discussion Starter #5
I replaced the HE in an attempt to keep things cooler. I use 91 Octane (USA) and 100, no help. There is no knocking, just a power reduction when hot. How did the IC replacement help your Charge cooling? I don't think replacing parts is the solution, there is definitely something not right as this should work as configured. Weistec suggested the exhaust flap could be defective and that would likely be something to explore as that would cause power issues. I did a full ODB log (HP Tuners) and sent it to Weistec and they said everything looked normal.
 

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I replaced the HE in an attempt to keep things cooler. I use 91 Octane (USA) and 100, no help. There is no knocking, just a power reduction when hot. How did the IC replacement help your Charge cooling? I don't think replacing parts is the solution, there is definitely something not right as this should work as configured. Weistec suggested the exhaust flap could be defective and that would likely be something to explore as that would cause power issues. I did a full ODB log (HP Tuners) and sent it to Weistec and they said everything looked normal.
I would agree - replacing parts and throwing money isn't the solution, that is not what I suggested. I am stating that heat soak can occur on the Intercooler itself, other than the core. I never see more than 10° from ambient with a stock Exchanger and Alpha Intercooler. running 36PSI... I have never logged a need for upgrading then aux or main exchangers

If Weistec says its good, then ECU calibration is soft validated? do you mind posting your .hpl file, maybe a second set of eyes?
I am not familiar with the exhaust flap, if that would cause any issues or if there are ways to bypass (manually open) to confirm.
 

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Discussion Starter #7
I'll try and find the log file, thanks! This was their response to my dealer fault report:

P13C700 The exhaust flap has an electrical fault or open circuit
That code causes a soft limp mode that limits power. This could likely be the cause of what you have been experiencing. the valves go bad and get jammed up. If too much force is needed for the motor to open or close the valve or if the valve cant reach its limits, it causes the code.

P1CE700 Crankcase ventilation in WOT operation (cylinder bank 1 has a malfunction)
This code can be caused by an airbox leak or being at full throttle well below the boost threshold. It does not cause any kind of limp mode.

P026A00 The efficiency of the charge air cooler is not sufficient
This would reduce power as well.
 

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I'll try and find the log file, thanks! This was their response to my dealer fault report:

P13C700 The exhaust flap has an electrical fault or open circuit
That code causes a soft limp mode that limits power. This could likely be the cause of what you have been experiencing. the valves go bad and get jammed up. If too much force is needed for the motor to open or close the valve or if the valve cant reach its limits, it causes the code.

P1CE700 Crankcase ventilation in WOT operation (cylinder bank 1 has a malfunction)
This code can be caused by an airbox leak or being at full throttle well below the boost threshold. It does not cause any kind of limp mode.

P026A00 The efficiency of the charge air cooler is not sufficient
This would reduce power as well.
Exhaust flap does sound like an area to focus on.
HP tuners doesn't have control over the exhaust flap to set the DTC fault class = disable to try it out. (validate ). Maybe Weistec can? Or fix the exhaust flap valve?
 

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Discussion Starter #9
FYI - Here was my run (20 min) at Laguna Seca this weekend, you can see it was not driven hard AT ALL, too much traffic to really open it up. I got black flagged for passing the Shelby Mustang that wouldn't get out of my way after 2 laps. Every time I stepped on the throttle, it was too restricted and I quit my last 2 races.

 

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P1CE700 Crankcase ventilation in WOT operation (cylinder bank 1 has a malfunction)
I’d try to look more into this code. It’s kind of a “phantom” code where there’s quite a bit of discussion of it with the m133 motor (mostly on the A45 forums) and some other Benz’s but no one ever really comes back with a solid fix. There are multiple reports of power loss though with no limp mode. Try to plug just the code into Google and you’ll find a lot of threads about it.

I actually had this code on my old (2015) GLA45. The car was at the dealer for something unrelated when they found it so I didn’t pay as close attention to the repair as I could have, but they blamed it on the engine cover rubbing the vacuum hoses (the silver/black hoses coming out of the front right of the engine cover). Early m133 covers seem to be a few mm to short. I know youve done mods, but maybe double check that your engine cover isn’t rubbing the hoses?

The kicker was that they said they needed to replace a bunch of stuff altogether for the fix which included the coolant reservoir under the engine cover. All in all it would’ve been $1400+ without warranty.
 

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Discussion Starter #12
Actually, my vent tube running under the engine cover has significant damage to the shield AND hose underneath. I am working with an EU guy who is selling branded hose kits for the replacement.
 

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Definitely look into this. Don’t want to draw any premature conclusions but the hose being damaged too throws a pretty big flag out IMO.

The symptoms from the crankcase vent code seem to be... lack of power at the higher end of RPM’s/WOT, no limp mode, and no dash CEL (just a stored code). Some people don’t even know they have the code, but I would guess these are grocery store cars that don’t get pushed to limits where it’ll really show.

I don’t have the 2015 anymore, but I could try to dig through my old service reports for part numbers for what they replaced.
 

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The exhaust flap is the only topic in this thread I can comment on, the rest is way over my head :)

That flap is on the right side of your dual exhaust and is a simple butterfly valve that severely restricts gas flow out that pipe. It's controlled by a simple motor bolted to the assembly and is super-easy to access under the rear bumper. It's held in place by 3 8 or 10mm bolts (I forget which size). The motor, not the flap. The flap is integrated into the exhaust. You probably knew this already.

The motor is connected to the flap using a rigid clock spring. that clock spring is the diameter of a 50-cent piece, made of coathanger wire, and is brittle as heck. It is very easy for that spring to snap, and then the motor can't control the flap anymore. Loosey goosey.

Under hard acceleration (including with a "lowly" 350 HP), the gas passing through that pipe is enough to make the flap move, as friction forces are not enough to hold it in place. I don't remember, if the flap gets pushed CLOSED under acceleration, or OPEN. If it gets pushed CLOSED, you could be choking off your exhaust, building heat down there, etc etc.

^^^^ this is how I originally found I had this problem. I was accelerating (normally) from a stop light in a 35 zone with all 4 windows down when the exhaust sound changed very very suddenly. the flap was snapping out of place (open or shut, I forget which). Could only hear it with the windows all down.

This is an easy hypothesis to test. In the driveway, pull the motor. If half a clock spring falls into your hand when dropping the motor, you may have a smoking gun. The loose bits of the spring were jamming up the motor, bad feedback on position, and thus the code thrown. The spring is not "user serviceable", the dealer makes you buy a whole new motor at $300. Folks on the board here found an infinity part# (I think) that's the same part for half the cost. You can search that out.

Though frankly your dealer should have already done this if they pulled that code....

If the spring is good, might be misalinged and locked your flapper closed. Then you just re-align at re-install and GTG.

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First troubleshooting I would do is get the car nice and hot (15 minutes driving should do it), and pull over when in sport mode and check if the flap is open. It's super obvious when that flap is open vs closed based on hot gas ejection from the pipes. if closed when running sport mode and warmed up, you have a problem.


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Everything in this post is only commentary on the hardware. I make no claims about how it relates to your power issue, that's above my pay grade. But that hardware, I know it. It failed on me 200 miles before my warranty expired and was the last and only repair done to my car on warranty.
 

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FYI - Here was my run (20 min) at Laguna Seca this weekend, you can see it was not driven hard AT ALL, too much traffic to really open it up. I got black flagged for passing the Shelby Mustang that wouldn't get out of my way after 2 laps. Every time I stepped on the throttle, it was too restricted and I quit my last 2 races.

My kind of laps! I wouldn't even need to take driving lessons before trying Laguna Seca if there was always this kind of traffic! 40 mph haha.

Question, is the accelerometer set to 1G at the ring? despite being slow, you're still cornering quite hard. Unless its 0.75 or 0.5 in which case it seems like a traffic jam!

Thanks for sharing this. You're making me want to skip any research into race school and just go start driving Laguna Seca.
 

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The exhaust flap is the only topic in this thread I can comment on, the rest is way over my head :)

That flap is on the right side of your dual exhaust and is a simple butterfly valve that severely restricts gas flow out that pipe. It's controlled by a simple motor bolted to the assembly and is super-easy to access under the rear bumper. It's held in place by 3 8 or 10mm bolts (I forget which size). The motor, not the flap. The flap is integrated into the exhaust. You probably knew this already.

The motor is connected to the flap using a rigid clock spring. that clock spring is the diameter of a 50-cent piece, made of coathanger wire, and is brittle as heck. It is very easy for that spring to snap, and then the motor can't control the flap anymore. Loosey goosey.

Under hard acceleration (including with a "lowly" 350 HP), the gas passing through that pipe is enough to make the flap move, as friction forces are not enough to hold it in place. I don't remember, if the flap gets pushed CLOSED under acceleration, or OPEN. If it gets pushed CLOSED, you could be choking off your exhaust, building heat down there, etc etc.

^^^^ this is how I originally found I had this problem. I was accelerating (normally) from a stop light in a 35 zone with all 4 windows down when the exhaust sound changed very very suddenly. the flap was snapping out of place (open or shut, I forget which). Could only hear it with the windows all down.

This is an easy hypothesis to test. In the driveway, pull the motor. If half a clock spring falls into your hand when dropping the motor, you may have a smoking gun. The loose bits of the spring were jamming up the motor, bad feedback on position, and thus the code thrown. The spring is not "user serviceable", the dealer makes you buy a whole new motor at $300. Folks on the board here found an infinity part# (I think) that's the same part for half the cost. You can search that out.

Though frankly your dealer should have already done this if they pulled that code....

If the spring is good, might be misalinged and locked your flapper closed. Then you just re-align at re-install and GTG.

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First troubleshooting I would do is get the car nice and hot (15 minutes driving should do it), and pull over when in sport mode and check if the flap is open. It's super obvious when that flap is open vs closed based on hot gas ejection from the pipes. if closed when running sport mode and warmed up, you have a problem.


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Everything in this post is only commentary on the hardware. I make no claims about how it relates to your power issue, that's above my pay grade. But that hardware, I know it. It failed on me 200 miles before my warranty expired and was the last and only repair done to my car on warranty.

I had the code P13C700, though I did not even realize there was a problem. I actually brought the car in because I began to have a battery issue. I suspected prior owner from lease did something to allow the battery to drain down, and even with recharge batteries usually are damaged at that point. Anyway, the car then started showing the check engine light. So when I brought it in, sure enough the battery had to be replaced but they also found the spring on that exhaust valve had also broken, likely why the check engine light came out they suspected. This appears to be a common problem. I'd like to just disable it in some way as to not throw a code and leave it open for the dual exhaust.
 

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Discussion Starter #18
My kind of laps! I wouldn't even need to take driving lessons before trying Laguna Seca if there was always this kind of traffic! 40 mph haha.

Question, is the accelerometer set to 1G at the ring? despite being slow, you're still cornering quite hard. Unless its 0.75 or 0.5 in which case it seems like a traffic jam!

Thanks for sharing this. You're making me want to skip any research into race school and just go start driving Laguna Seca.
You don't need a class. This is a high performance drivers education. It includes instruction and instructor led laps on the track. Only in the afternoon are you turned loose.
 

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Discussion Starter #19
You don't need a class. This is a high performance drivers education. It includes instruction and instructor led laps on the track. Only in the afternoon are you turned loose.
You can easily exceed 1g, especially if the turn had any bank to it
 

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In the coming weeks I am going to send you a PM for more details to not thread jack. Looks like you are going on the Exclusive Track day. Cheaper than a day at Pebble Beach!

Anyway, I am very curious about the result of checking that exhaust flap. It would be super to learn if that is causing upstream temp issues and responsible for all the power problems.
 
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