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Hey guys! I was curious what everyone's thoughts are. I have an issue of what seems to be like my in tank fuel pump cannot keep up in the mid to high RPM ranges when I am trying to go WOT or at speed. I noticed at specific points, my rail pressure will drop from 2400's to the low below 500, but I can do 3/4 throttle and be mostly fine. I am tuned on E40 with methanol injection.
E40 and Meth or just E40?
it is both. I figure a surge tank is my best betQuote:
Originally Posted by chevota
Sounds like a delivery issue. The factory system can handle more than E40.. especially if the meth is adding a bit of fuel.
That was my understanding as well. I figured the low pressure pump may have been weak, so I bought a new one and swapped it in with no change, I don't think it's a high pressure pump though since everywhere else across the board is sitting in the mid to high 2400's for pressure
I've run up to 40% Ethanol ( adding E85 + the 10% already in the gas) and never leaned out, even with an excessively rich mix and no Meth.
I would've assumed the HP pump would drop psi at any load when it fails, but just an assumption. From what I recall, people with flow issues had LP pump problems or filter clogging. Makes me wonder if there's another filter between the LP & HP? If I had designed it I would've put a screen filter in there in case the LP lets go or seals/rubber or whatever pops loose. They say Eth can eat our rubber goodies so if there is a filter I rekon if could be full of rubber.
Another thought, maybe a long shot, is if the cam lobe or the pump rod (or however it actuates) is worn and no longer gives full stroke, then I'd assume full psi until it can't keep up. Half stroke, half volume, etc...
The latest HP Editor has a section to mess with LP settings but not sure what it does exactly. All I know is my OE Tune had those changed. I tried those settings for a few days just to do it, but otherwise I leave it oem. The thought was maybe do that and see if makes any difference, which might be a clue?
Did this start when you used Ethanol or was it fine "until one day"?
Can you post the tune and a Scanner run showing it? psi
Here's the LP mod. All the tuned version is oem x 1.05 which changes the 177 to 185.5 etc
All the variations under Lift Pump were the same and all x 1.05. Not sure if yours has that option but fyi
Attachment 130057
It started right before I put in ethanol after I installed new air intakes and an ethanol sensor. I figured the sensor was a restriction at first so I added in an ethanol sensor bypass with 8an line in that area to ensure there was no restrictions, also with no change. Funny enough, there are moments where I can actually floor it and there are no issues, then other times it's like the pump can't keep up.Quote:
Originally Posted by chevota
I have played with thay screen a bit! I upped the flow to match the AMG values a little bit and put an increase in flow in the middle of the RPM range as well and tried a few different things, but also with no change.
Here is a log, but the tune I can't post.
Attachment 130058
Ethanol sensor you say? I'm running without a sensor or tune for it.
Eth bypass? Wth is that? A parallel line?
What kind of intakes? Did you $pend the big $ on Black Box?
Can't post the tune or won't :( I was curious to see what you were up to in there... Plus I have a weird idle issue and was curious if you did too, or if your tune has a fix. Ethanol is, imo, only partially to blame but basically I adjust Slope for the Eth than at idle it randomly seems to ignore the slope setting and my trims max out and cause a fault. The less slope I add the less of an issue it is, so I have it set to about half what it should be and it stopped faulting out.
Interesting that it started after the mods, but before Eth, yet sometimes works fine. Hmmmm.... What about the tune? Did it happen before or after?
I just looked at the run. Help me understand what happened at 06:01:05 on down to idle?
The pressure drop is drastic, so I wonder if it's cutting fuel rather than running out of it? But I also assumed a fuel cut was at the injectors, not the pump, but maybe it cuts the pump with certain errors and Inj with others? There are some settings in there that I believe prevent cutting the pump. Well, lets say I adjusted them and also don't have issues, if they're related I can't say for certain.
You need to add Injector Pulse Width so we can see wth it's doing. Both to see how much its dumping in, if it's cutting or adding when psi drops.
There may also be one for Fuel Cut, if I recall correctly? I think that one is simply 0 or 1 and apparently it flips to 1 when it cuts fuel.
So right now I'm leaning toward the ECU isn't happy and is causing this, which would be much better than hardware causing it, but hard to say, especially without Inj pulse width data
This is looking more like high pressure pumps to me. I have a log very similar to yours back when 1 or both of mine were failing. I replaced them and it resolved the issue.
Yep, The fuel here is pretty inconsistent with ethanol content so I like to see what is actually going into the motor. The bypass just allows more flow by running a parallel path next to the sensor removing the possible restriction, so half the fuel in the line goes through the sensor itself, and half goes around the sensor to allow for a higher flow(look up the Motion Raceworks ethanol sensor bypass and that whaat I am using). The way I'm building the car is overkill but I have big plans for this car in the future as my wallet allows lol.Quote:
Originally Posted by chevota
The intakes are 3D printed intakes flow tested and printed by me, same concept as the blackboost intakes though, but to just allow a cone filter for more airflow.
More of a can't, I paid for the tune but it was done through HPT. I don't have any idle issues or anything, the car runs beautifully outside of the one single issue with fuel. for your issue, have you tried going back to the stock tune to see if it still there?
I want to say the timing of installing the mods is coincidental, I did swap the original boxes back on and such but it also did not change anything. But looking at the log, the pressure drop is way too drastic to be an airflow issue it looks like. It happened before the tune as well. Also funny enough, we played with the pump controller to have the pump flow at ML63 specs and such and it did go away for a short time.
It does almost look like a fuel cut in a way, but that pressure drop is why I think the pump is not keeping up rather than fuel being cut from the cylinders. It would be a weird thing for the pump to just stop to cut fuel flow. I'll see what it looks like adjusting the pw just a tad, it's worth a shot, but I didn't see a channel available to see if fuel was being cut or not or to show the pw.
If I do keep the throttle down though without letting off, the ECU gets pretty unhappy and shuts the throttle until the car slows down a bit, and I can drive like it never happened again.
Don't put that bad juju on me! :pray: But either way, if that is the case, at least they are easy to get toQuote:
Originally Posted by Schnell
Here's my fuel psi settings vs oem. That super low Min and Error psi is what made me think of you.
Attachment 130062
Attachment 130063
And lastly, fuel cut. You may not have it but this is where mine is hiding. Inj pulse width is right under it
Attachment 130064
Quote:
Originally Posted by wes1311
Have you tried reverting back to stock file with only pump gas and check if it acts the same way? if yes then its an issue with the car not the tune
I noticed you had "Fuel System #1 Status " saying CL - Fault through the log file
Add Fuel System #2 Status and check whether its the same or not