\\ RENNtech R1 Package Issues //




Dealer seems to believe wastegate is perfect and refuses to touch tune-related problems which is obviously understandable.
Read through a little, my battery voltage is fine and dealer believes vacuum lines are all in good shape. Going to do some more reading through but I do have an ‘Auxiliary Battery Malfunction’ right now but it seems to be a very irrelevant fix to something like this. They wanted to charge $408 for it so I’ll just get on YouTube and figure it out myself, assuming it’s easy.
Different tuners… so X factor is definitely something with the car and not the tune.
Fyi 5% turbo boost solenoid duty cycle is the minimum allowed, so if it stays at 5% it means the ECU turned the turbos Off, which it does when it sees overboost, which I see it did, and there we go... Well, I assume, but it doesn't say PSIA or PSIG. Default is PSA
I don't an actual overboost, but rather too much boost at the wrong spot. So it could be the tune is a bit much at low rpm or could also be as simple as the bleed port filter on your turbo solenoid is dirty. You can pop it off for a look-c, maybe leave it off and see if the issue goes away. Basically, if restricted, the wastegates are slow to open and boost climbs too fast to soon. They're already slow to respond so it doesn't take much to fault out. Another is oil in the lines and/or diaphragms, because they slow wastegate movement and same result.
I had similar issues with mine, E550, M278, where the boost would fault out sometimes. It was my fault, tinkering with the tune, but there are settings on there to make it stop, which I did using HP Tuners. I've heard using HP over another tune will wipe the orig tune, but it didn't on mine. I think it has to do with how the tunes are pulled from the car, or not, by HP. Apparently some are not, cannot, be pulled from the car so it pulls an oem copy on an HP server, then you tweak it. If you load that, then you just loaded an oem file with your tweaks over the tune it had. At least that's how I understand it. But if I can do it I'd imagine you can since I believe we have the exact same ECU? At the very least your tuner could do it, because if I can they can.
Optionally, you can get another ECU and clone it to your car, then tinker away without having to worry about breaking it. This is what I did and it cost me like $200 for a junkyard ECU and ~$80 in goodies to do the clone. Cheap insurance imo.
I would for sure check the filter and for oil first. If that check out I'd want to see the tune, which I don't know if I could even if you used HP to look at it?
Well, look at those and post what you find.
Not that I think these are your issues because these cause low boost, but fyi since I learned the hard way and wished someone had told me:
The vacuum pump has a little check valve just for the turbos that tends to break and cost you vacuum, and thus boost. Very easy to access btw, behind cyl 8. Just follow the vac line. Buying a cheap chinese replacement valve is not the answer imo. It may work for oem boost, maybe, but it's simply unsat because they cheap out on everything. Even the better orange check valve is not as good as oem. Better than a broken one, and maybe try it until you find a real one, but from what I can tell you need to buy a while vac pump to get a new check valve, which is this teeny little piece of silicone that you can't make yourself and apparently costs far more than it's wt in Gold.
Voltage is very important, I discovered, the hard way. Voltage drops when under load, for some reason, and apparently this is normal. If your vacuum is not up to snuff it'll take less voltage drop to hurt you. Or, like me, my vacuum is good but I have a greater voltage drop than normal which was killing power. I've been unable to fix the voltage but I was able to change the duty cycle on the boost solenoid from 90% to 100% which made all the difference.
Changed out the vacuum pump piece that holds the orange nipple. When the old piece was taken out, the orange nipple did not even exist, assuming it might have been completely destroyed. Oil leaked out of the opening when it was taken off. The hose end snapped due to brittleness and I’m using a makeshift fix for now until I can get replacement, drives fine.
Interesting difference: car now drives a bit better in tuned form, very similar rolling numbers to stock (within 0.3 seconds), dig times start off well but drop off somewhere around 50-60 MPH. The loss in boost/throttle is actually very noticeable at those speeds.
I scheduled a service appointment with Mercedes to have them use my aftermarket warranty to hopefully replacing the entire vacuum pump under warranty due to leaking oil. Wish me luck, any advice is appreciated.

So when you lose power ~50-60 is it showing on your app that the turbos dropped out again, or just petering out? If you have the boost psi and duty cycle chart like before, plz post


So when you lose power ~50-60 is it showing on your app that the turbos dropped out again, or just petering out? If you have the boost psi and duty cycle chart like before, plz post

Dragy 1/4 Mile Tuned: 11.66 @ 117.93 MPH (same run as attached)
Dragy 1/4 Mile Stock: 11.87 @ 118.43 MPH
DA was 1765, slight incline and slight turn during run, same spot for both
Snapshot below is at peak of run
The Best of Mercedes & AMG
Dragy 1/4 Mile Tuned: 11.66 @ 117.93 MPH (same run as attached)
Dragy 1/4 Mile Stock: 11.87 @ 118.43 MPH
DA was 1765, slight incline and slight turn during run, same spot for both
Snapshot below is at peak of run
Add at minimum Knock Retard Cyl 1, Knock Retard Cyl 2, etc., as well as WB EQ Ratio 1 and WB EQ Ratio 5, and also turbo wastegate DC
Add at minimum Knock Retard Cyl 1, Knock Retard Cyl 2, etc., as well as WB EQ Ratio 1 and WB EQ Ratio 5, and also turbo wastegate DC
Those neg spark timing dips can be prevented too, of you want. Mine was doing the same and it drove me nuts, so I blocked it.
Seems like the blow-off valve is bleeding more than it should? Meaning too low a psi. If it were me I'd just lock it closed while you're tinkering, or at least up the psi so it's not so annoying. There's a setting in HP to greatly reduce the psi spike when shifting or letting off, which is what I do and it's plenty, so I have zero need for a blow-off.
Your intercooler pump should kick On sooner. Even with the oem settings I never see intake temps ramp up so fast, or so high. I'd ask the tuner to lower the On temp and set the min duty cycle at like 30% or something.
You need to add more stuff to the Scanner. I'll make a list

The really good news, for me, is I'm quicker
Just barely but I'll take it. Up until now I had no data from any car with similar power to compare it to. I think once you fix the octane issue that will change for me, but meanwhile I can somewhat claim bragging rights 
Did you just get HP Tuners, or did you already have it? Are you going to mess with the tune via HP, or just to data log? If you mess with it I would back it up first!
It would be interesting to see if an HP tune could net the same or better times as the big $ tune. My guess is yes.
The attached file (HP Settings.rar) is a type of zip file. Any zip program should open it. Inside are my files to make the Scanner like I posted a few posts up.
"Layout" is for the overall position of the windows
"Channels" are all the goodies you're monitoring, on the left side. Your PID #'s may be different for some things, so use the attached pix to find them in yours
"Gauges" are for the gauges
"All Charts" is the charts
I also included my Math goodies, Boost PSIG, Fuel Trim Avg, Horsepower, Knock Avg, MAP PSIG, and Wheel Spin (if you have a 2WD like me it's handy)
>>> Edit; almost forgot. There is a file in there called "VCM Scanner.cfg". I believe if you replace yours with this you'll simply get all my settings and don't need to do anything else. Swapping your old one back will give you all your old settings back like it never happened.
I don't use the window you have in the upper right because I found it completely useless, and I made much better use of the space with gauges. If you have any questions about HP, feel free to ask.
Last edited by Chevota; Jul 10, 2023 at 07:59 PM.
Those neg spark timing dips can be prevented too, of you want. Mine was doing the same and it drove me nuts, so I blocked it.
Seems like the blow-off valve is bleeding more than it should? Meaning too low a psi. If it were me I'd just lock it closed while you're tinkering, or at least up the psi so it's not so annoying. There's a setting in HP to greatly reduce the psi spike when shifting or letting off, which is what I do and it's plenty, so I have zero need for a blow-off.
Your intercooler pump should kick On sooner. Even with the oem settings I never see intake temps ramp up so fast, or so high. I'd ask the tuner to lower the On temp and set the min duty cycle at like 30% or something.
You need to add more stuff to the Scanner. I'll make a list

The really good news, for me, is I'm quicker
Just barely but I'll take it. Up until now I had no data from any car with similar power to compare it to. I think once you fix the octane issue that will change for me, but meanwhile I can somewhat claim bragging rights 
Did you just get HP Tuners, or did you already have it? Are you going to mess with the tune via HP, or just to data log? If you mess with it I would back it up first!
It would be interesting to see if an HP tune could net the same or better times as the big $ tune. My guess is yes.

The question on my mind remains, can you use HP over your tune or not? I think I mentioned there is concern over trying it, but it just might be propaganda to scare people from copying an expensive tune. If so, it seems to be working because I'm unaware of any tunes copied with HP, except the one I did. The only issue I had with HP and the aftermarket tune is once I used the HP patch on the ECU, the hand held MyGenius tool I used to load my tunes would no longer cooperate :o It sees the ECU has been tampered with and simply refuses to work again. The "patch" is some mystery bit of data that needs to be added to some Mercedes ECU's before the HP Editor can be used. My guess is it the patch upsets the checksum, which My Genius sees? I hear smog checks now look at the checksum, so all the more reason to keep a backup copy of the oem file.
Not sure if you loaded your tune with MyGenius or not, but I did and this is how I managed to avoid that issue: I had the stock oem tune on the ECU, which I assume you also have? And two aftermarket tunes, one for 91 octane, one for 100 oct. First I backed up the oem ECU tune using KESS, to be sure I had that safe n sound. Once I had that copy safe and sound on several hard drives I was free to do whatever. With the oem tune on the ECU, I loaded the HP patch, then and copied that oem tune with HP. The HP copy of the tune is not the same as the KESS btw. KESS does the entire ECU, like a Ghost image of a computer hard drive. HP apparently only copies the parts it sees as most important for tuning, like a generic backup of a computer has the important data but you cannot restore a computer with it.
I then used the MyGenius to load a tune so I could copy that, and that's the moment I learned it won't work after using HP. Thank (insert your gods name here) I backed up with KESS first! So I reloaded the ECU with the KESS backup, then tried MyGenius again and it worked. I loaded a tune into the ECU, then loaded the HP patch again and copied the tune with HP. Repeat for the last tune, and done.
Yeah, that took a while... Plus I had to learn how to make a backup of the ECU using KESS, which is easy now that I know, but it was not when I didn't because there was very little information about it, and what I did find was cryptic. Plus my ECU was not on the list of ECU's KESS or K-TAG works on.
Lucky for you, we have the same ECU and I'm happy to share all I learned. I even made instructions with pictures and arrows to help others. Fyi do not follow the instructions that come with a KESS or K-TAG, or from the website, because their version is substantially more difficult and risky.
Also note; the patch is known to, on occasion, brick the ECU. I know a guy online that bricked his. He had a CLA 45, with a different and more finicky ECU, which may be why? I'm unaware of our ECU having that issue. I've loaded the patch on two ECU's (ours) ~ five times. I mentioned I also have a backup ECU, which I also tinkered with, so at least five times. Bricking, while unlikely, is yet another reason to backup your ECU before tinkering.
Note; as mentioned, HP only sees the more important things in your ECU. Rumor has it that places like Renntech will also adjust some settings HP can't see. Probably true, but HP does see the most important things and I can tune mine to squeeze the max possible power with it, so what more do I really need? Sure there's things I'd like to do but can't with HP, but they don't relate to power. No ideal how important these mystery settings are, but I wonder if you had the Rentech on it, used HP to copy and made changes and loaded it back on, will all the mystery settings remain intact and only your changes are different? There is a guy online that says he bought a 550 that the seller claims has a Renntech tune, and he used HP on it no problem. I'd assume it would simply make the changes you do via HP and nothing more, but I have no way to confirm it.
If you have Renntech adjust your spark timing I doubt they will be interested in truly dialing it in. It took me a long time to get mine dialed in on pump gas, which is just enough retard at each point to keep the ECU from pulling timing, or power. My guess is they will simply retard the entire map by 3 deg or more and call it good, which be a bummer but also means it'll run hotter. I see you're on the hot side already, imo. HP settings can cool it down fyi. I never see the temps you were hitting.
Fyi the pix below is what I retarded compared to oem. This is one neat feature of HP, you can compare two tunes and it'll show you the difference like this. Super handy...
Using E85 to eliminate my ping/retard took about 30% Ethanol. Super easy to do, and like me, you'll see the power difference instantly. Keep in mind the Ethanol is only netting a little bit of the power, almost all the gains come from the ECU not pulling power. Your retard looks pretty much like mine does on Gas, maybe a little less, so maybe 20-25% would work for you? Only one way to find out. That's % includes the 10% already in the gas btw, so you have to do the math to figure it out. Well, assuming your gas has 10% in it, but I think it's standard across the US? I made an Excel sheet to do the math it if you go that route, but 30% for me is ~5gal E85 and 12.5gal Gas for my 17.5gal tank.
The fuel system will have a limit of how much Ethanol it can handle. Basically it can supply xx% fuel over and above stock needs, so when you tune you need more, and Ethanol needs more. Who knows how much room you have but mine can take 50% Eth no problem with the tune maxed out. No tune and I'd imagine it could run pure E85. I dumped 20% in right off the bat. If it had leaned out under load I'd simply let off the gas and go fill up again.
There is also concern about Ethanol hurting the fuel system. Not sure if it hurts our cars or not, but it certainly can damage many cars. How much Eth it takes to hurt a car, or our cars, and over how much time, I don't know. My guess is 25% won't hurt it, but what do I know. So as a precaution I've been adding Lucas Fuel Injector Cleaner, which is probably just Mineral Oil with some solvent added. I add 4oz to a fill, which is usually 14gal.
Your eng is virtually identical to mine, so imo it would be easy to tinker with. Plus, I think almost all people who use HP on a Benz are using it on turbo engines, and I think most are 63's and second place is likely the 550's, like mine. So while HP tuning info on a Benz is scarce, I think you have the most popular car for it. And, if all fails, which I doubt, there are professional tuners that use HP, and will hook you up for a fee. How much I don't have a clue because I want to do it myself, but I can't imagine it's very expensive. They no doubt have a file ready to go and email it to you. Unlike the typical paid for tunes, you can copy it to another 63, or even copy the gist of it over to a 550 if you want. I've used some 63 settings but I like my settings better.




Is there any way to test/diagnose the injectors without pulling them?
Last edited by SpecR; Jul 11, 2023 at 08:42 AM.
The main thing is that both the stock and tuned run parameters look much closer than I'd expect. I'm not a tuner, and not claiming to be an expert, but the 3 things I normally look at are boost pressure, timing, and air-fuel ratio. The boost pressure and timing don't look increased, and the air-fuel ratio is just leaned out a little (still safe). From these, I would guess that you see pretty much no change in the tuned runs vs. stock. The random knock that shows up occasionally could make one or the other slightly better at any given time. Can you ask Renntech what boost and timing you should expect? The tunes I've had from Eurocharged and ECC show obvious differences in boost & timing.
I believe you'd previously mentioned that Renntech proposed that the BOV/BPV was installed incorrectly and could be leaking. Were you able to test without that component? The turbo wastegate duty cycle is pretty much identical between stock & tuned, and I would guess that if the tune was making the turbo push out extra boost, even if it was then leaking out the BPV, the WGDC would be higher. Perhaps there is some mitigating factor, but all the above would make me assume that the tune is just really weak and not beneficial - certainly not worth Renntech $$$.
The main thing is that both the stock and tuned run parameters look much closer than I'd expect. I'm not a tuner, and not claiming to be an expert, but the 3 things I normally look at are boost pressure, timing, and air-fuel ratio. The boost pressure and timing don't look increased, and the air-fuel ratio is just leaned out a little (still safe). From these, I would guess that you see pretty much no change in the tuned runs vs. stock. The random knock that shows up occasionally could make one or the other slightly better at any given time. Can you ask Renntech what boost and timing you should expect? The tunes I've had from Eurocharged and ECC show obvious differences in boost & timing.
I believe you'd previously mentioned that Renntech proposed that the BOV/BPV was installed incorrectly and could be leaking. Were you able to test without that component? The turbo wastegate duty cycle is pretty much identical between stock & tuned, and I would guess that if the tune was making the turbo push out extra boost, even if it was then leaking out the BPV, the WGDC would be higher. Perhaps there is some mitigating factor, but all the above would make me assume that the tune is just really weak and not beneficial - certainly not worth Renntech $$$.
Since I'll be in the Mercedes dealer next Thursday, does anyone have any recommendations on what to ask them to look at? They are uneasy about the tune for obvious reasons but my stock performance has inconsistencies too so they should have a valid reason to check something that might not be working properly.








If intake temps rise too much car will pull timing, close throttle blade, lower boost for example.
Last edited by PekkaH; Jul 12, 2023 at 08:47 AM. Reason: edit
If intake temps rise too much car will pull timing, close throttle blade, lower boost for example.
I appreciate all the advice and suggestions. This has been way more of a pain in the *** than I ever could have imagined…




