got this code triggering the Check engine light checked out through star. Showing catalytic converter of the right cylinder bank. Showing its the kat and not necessary to replace either oxygen sensor from right back. Any thoughts?

 

Swap post cat sensors left to right. If error moves to other bank - it is the sensor. If it doesn't- it is the cat

 

Great idea alx ill try that and see how the values are coming up in star

 

Damn lengths are different

 

 

Properly cared for, the plugs last near forever. I changed mine at 100k miles, and not only did the center electrode still look respectable (that's what wears), but saw no improvement in performance with new plugs. Running the engine way lean would erode them faster (I think) but that's basically impossible to do without issuing P codes all over the place.

It's possible your plugs are fouled, but you'd have P codes that would reflect this. P03xx.

I got a 420 error 35k miles ago. I ran cat cleaner (Guaranteed to Pass) through the tank and saw the errors twice again, and passed smog. I never got around to changing that sensor. Cats do get fouled. If my cats are going bad, they aren't doing so very quickly.

The post cat oxy sensors check the effectiveness of the cat. If you don't have pre-cat errors, e.g. sensor fault or mixture fault, the system is honestly reporting cat inefficiency. I would definitely try cleaning them before replacing, as doing so is expensive. Depending on your state, you may be able to get an aftermarket cat welded in. If you go factory parts, you have to replace a lot of the exhaust. I think it's exhaust manifold back to a junction about six feet down.

Because the post cat oxy sensor is what is being used to trigger the 430 error, it's unlikely that anything upstream, besides the cat, is causing it. It's possible it's the post cat oxy sensor, which is a cheap thing to test with parts.

Not sure, but I'd guess your tumble flap (intake manifold) is responsible for the low rpm roughness. There are fixes for this that do not involve replacing the entire manifold. You simply replace the broken linkage.

So if I were you, I'd, in order:
1) clean the cats
2) replace the post cat oxy sensor(s)
3) replace the cat(s)

Also get that tumble flap linkage fixed. It's not an expensive fix.

If you don't have one, get a bluetooth OBDII module (<$10) and read codes via Torque Lite (free app for your smartphone).

Good luck, and report back with your results.

 

 

 

Top plug looks fine. Next plug is kinda bad but not that bad. It's alarming to see the plugs different. Since you put in new plugs, check them in a thousand miles or so. You get weird plugs on the hot side when there is a fuel injector problem and one cylinder runs lean, or cold (black) when there is a spark problem. I'm surprised you didn't have a 3xx error with one plug looking like that.

Hope you kept track of which plug came from which cylinder. I sharpie the numbers on the insulators.

Air filter isn't that bad, but it's so easy to change, there's little point in skimping. Note that with paper filters, dirty doesn't let more dirt through, but actually less, and resistance to flow worsens. So it's not as injurious as it might seem. The mass airflow sensor and upstream oxy sensor compensate for the resistance to flow.

Grease on the rear is commonly due to seepage out the cam hole plugs in the back. Nothing to be alarmed at, though the plugs and separator are a ridiculously easy thing to change.

The CEL will take a while to reset because the computer needs an interval of good performance to be assured it's actually fixed. I always reset errors after making a change, so as to quickly find whether the problem is fixed. Regardless, preliminary congratulations on positive results.

 

 

Not to keep the thread going unnecessarily long, but a quick tip on cleaning the injectors with Techron, etc. MBWorld user alx pointed out that the benefit of those solvents is in a hot soak. That would mean starting, warming up, and then stopping the motor. I guess this is better because if you just run PEA through in normal driving, most just races right past the deposits. I reckoned you could get something of the same effect by just leaving the motor idling; the fuel flow through the injectors is pretty slow at idle, so I figured the fuel would get pretty warm. I left the motor idling for several hours at a stretch, popping in now and then to check the catalytic converters' temperature. They never got hot, and I couldn't think of anything else in the motor that would be harmed by extensive idling. The motor did seem to run better after these sessions.

You also can get adapters that you put each injector in and spray carburetor cleaner through, after energizing the injector. This calls for you to remove the injectors, of course.

 

 

Honeymoon - lol, you're trying to avoid divorce court.

If you have intermittent failure on a coil, you should get pending 3xx errors. Remember, the system doesn't know what's actually happening when it fires the coil. If the power output from the motor is uneven, it will tell you so via the crankshaft position sensor; it's reading that the engine abruptly slows at a certain point in the cycle. I doubt that engine roughness you can feel is not resulting in a code.

Lubricate the air filter assembly clips with silicone grease. They clip onto these rubber posts, and it's easy for the clip to get bent. If they're lubed, you'll have an easier time wiggling around the air filter assembly. Same goes for how the MAF sensor fits in the elbow, etc.

170-175 are MAF sensor errors, meaning the system can't make sense of what it's reading from the sensor and how it's calibrating the mixture with the upstream oxy. You either need to clean the MAF or you have a leak past the MAF - 2 & 5 are "rich", which, considering you had a leak past the MAF, means it's telling you it's putting an unreasonable amount of fuel in, given what the MAF is telling the system.

I would not change a coil until you have a good idea which one is the culprit. Get that bluetooth OBD reader in and watch for codes. Since you seem to be the curious sort, I'd also recommend getting a computer like the MBII from Icarsoft. It's basically a step short of full on STAR. Just don't leave it plugged in; I drained a battery doing that.

Don't stress too much about the cat. If the system registers a misfire, it will go into limp mode, shutting off fuel to that cylinder. At least I think that's what it does.

 

 

If you have replaced all plugs and coils packs, another common failure point is the cam magnets. They are cheap and easy to replace. It may solve your issue.

 

Coil is probably still good. Hold on to it, or reinstall, keeping the new one as a spare for a legit failure. In my experience, when coils start to go, they tip catastrophically. The high voltage insulation starts to break down, and then arcs, and then the arcs blast a hole through the insulation.

Fix the tumble flap before you do anything else.

I don't know how to interpret those screen shots. Three misfires per driving cycle? That's start-stop cycle? We're talking 1000's of revs per minute. Three would thus be nothing. I'd say, if the computer isn't kicking out even a pending code, you're probably fine.

It could be a semi-plugged injector on #3. Try running the Techron, etc., through at idle. Ventilate your garage and leave it idling. If your OBD app tells you cat temperature, check that. Also oil temperature, but the cooling system is more than robust enough to tolerate extended idling. I wouldn't sweat it - meaning don't stand there in your hot garage like a nervous mother.

I understand that Techron only contains PEA; you can find it in lots of other tuneup-in-a-bottle products. I convinced myself that Gumout was the best PEA-for-the-buck product.

The MBII has graphing various data feeds, all kinds of Benz specific stuff.

Don't go by what the CEL does or doesn't do. Use it as an indicator to check your codes, and when you make a change, clear the codes. Driving around waiting for the light to turn off is unnecessary stress.

 

Maybe I missed it but how many miles on your GL?

 

85K on the GL, I finally caved and dropped it off at European mechanic since they have SD and I'm running out of time before a road trip this weekend. They suspected the intake manifold when I talked to them this morning, but I haven't gotten the call back for what is actually going on. Once I do I will update thread.

I kept the coil I took off so will be able to use that if/when another goes out. I even moved the new spark plug from Cyl3 to Cyl1 this morning, once I started the vehicle it was misfiring and did finally throw the P0303 code. The screenshot is from OBD Fusion app hooked up to wifi OBD2, the $06 onboard data did log those misfires and the other cylinders had 0 (screenshot is before P0303 registering).

If they call and say dirty injectors I'll definitely try the Techron before ripping into anything. Thanks again for everyone's support here.

 

Almighty, got the call back from the mechanics. They believe it is a leaky fuel injector causing the misfire.

They ran smoke tests, compression test, tested electronics behind injectors, moved coil packs around, etc.; and they said it is most likely a leaking fuel injector causing misfire at idle. While the recommended the intake manifold be replaced soon, they said the misfire is not from the manifold but rather the injector. The manifold is not registering codes to OBD but on DS they said they could see internal flap flapping around. They said Cyl1 is also registering misfires.

They are suggesting placing all injectors and the rail. How big of a pain is it to replace the injectors? Would the techron/Gumout help a leaking injector vs dirty injector? They said to do the manifold and injectors at the same time.

Why the hell would injector(s) fail at 85k?

 

Kek, they're throwing stuff at the problem all right. If you absolutely completely must have the truck in perfect shape before your road trip, then you don't have much choice. You're looking at a couple of grand in repairs, though, right?

If the injector is leaking out past the o-rings, heck, that's an easy fix. Change the o-rings. But you'd know from gasoline stink around the motor when it's idling, and this shouldn't cause any misfire.

If it's leaking because the injector is sticking open - not closing all the way - absolutely first try running fuel injector cleaner through. Go pick up the truck and stop by Walmart on the way home and pick up bottles of stuff that says "CONTAINS PEA!" on the label. Run it through; what's the harm? If the patient isn't better by tomorrow morning, then consider surgery.

My motto: Be conservative.

I have no idea whether 2011 injectors are worse than 2007, but these are really, really reliable components. The main thing they do is gum up and not spray the fuel in a fine enough mist. Then you need to run cleaner through it.

To be honest, these guys don't sound like top tier mechanics.

 

By the way, what's SD? DS? Do you mean DAS, as in Star/DAS?

 

Thanks, Eric! I actually called them back to say I'd like to pick up the car to figure out plan and he recommended running seafoam/detergent through fuel tank to see if that would work first. He also recommended doing intake manifold ASAP since the inside plastic piece can break off and get sucked into cylinder bending valve. Is it that dangerous for me to drive? I plan to replace within few months but just had front Airmatic strut, valve block, and rear shocks replaced so easing the mass exodus of cash would be nice for a little while at least. When I do get to manifold I'll most likely order from RMT and send back my old one, seems to be of high quality and nice price.

My mistake, I indeed meant DAS, I need to get my abbreviations straight!

If anyone wants to steal my GL it will most likely be idling in the driveway soon.

 

Just make damn sure you actually have to do the whole thing and not the external fix.
It's a little hard for me to imagine the plastic actually bending a valve, unless it props it so far open that the valve contacts the top of the piston on the up-stroke. The plastic could go right into the cylinder and - meh - so it melts and burns away. The cylinder is a violent and hot place. When you get it home, see if you can't jam the tumble flap into one position or the other. The broken lever may still be accessible.
It kills me that in the fourth model year MB still didn't have this straight.

No way. Them things are more trouble than they're worth.

 

Run the injector cleaner. You shouldn't have issues with the coil packs or cam magnets at that mileage. The flappy did not cause any issues on my GL. Maybe some low end acceleration but I didn't miss it. Never heard of s whole bank of injectors including the rail going bad on the GL.

If it is an injector seal, I would think you would be able to hear it with a mechanic's stethoscope and or smell the fuel. Good luck but I would do what Eric said above before you throw a bunch of money at the issue.