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Old 06-19-2015, 03:30 PM   #26
Bacon117
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Originally Posted by Psykostevo View Post
I am running e30, but have left stock Fuel Rail Pressure alone. Are you guys ramping up your desired Fuel Rail Pressure on the e85 tunes or something? I have just been modifying the Injector Trim tables to accommodate for the ethanol.

If you guys are looking for "head room" to allow for the longer Injector Pulsewidth, you could try to request the Start Of Injection angle to begin a little bit sooner. Right now the stock tune has the SOI at around 340* at high RPM and high load. You could bump that up to 350 or more degrees if need be. I realize that does almost jack squat, but it can help a tiny bit. You just always have to be mindful in your tune that your Injector Pulse does not overlap your ignition.
They are not talking about in tank pump, this is a direct injection pump that is driven off the cam. Pressures are much higher (~2000PSI).
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Old 06-19-2015, 04:55 PM   #27
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Bacon117: you sound so sure these issues are fuel pump & not tune related. Care to elaborate ? After running some E85 our WRX expressed its unhappiness by sputtering and stalling, surging. So did we ruin the fuel pump? Or did switching back to gas mask the symptoms. It runs fine on petrol but not so much on corn.
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Old 06-19-2015, 05:39 PM   #28
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Originally Posted by Bacon117 View Post
They are not talking about in tank pump, this is a direct injection pump that is driven off the cam. Pressures are much higher (~2000PSI).
I am 120% aware of that. I am not sure where you misunderstood that I said anything about an in-tank pump.

With stock Fuel Rail Pressure around 2,150 PSI mac requested, I was curious if the other tuners were raising these values to something higher, like 2,500 or so. I could see the higher requested rail pressure causing many issues on the pump, injector seals, etc.
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Old 06-19-2015, 05:41 PM   #29
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Originally Posted by MNC5 View Post
Bacon117: you sound so sure these issues are fuel pump & not tune related. Care to elaborate ? After running some E85 our WRX expressed its unhappiness by sputtering and stalling, surging. So did we ruin the fuel pump? Or did switching back to gas mask the symptoms. It runs fine on petrol but not so much on corn.
What Injector PW were you seeing? Got any logs? I created a calculator that takes the Injector SOI and the timing advance and calculates the maximum Injector Pulsetime, etc.

For example, I am currently seeing a very mild Injector PW on my e30 tune:



And here is my calculated max Injector PW by load and RPM using my calculator:



So with these calculations and a little margin for error and real life, I have plenty of available PW left on stock fuel pressure to accomodate a higher ethanol content, or richer AFR if needed.

Last edited by Psykostevo; 06-19-2015 at 05:46 PM.
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Old 06-19-2015, 05:54 PM   #30
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Ethanol and high pressure fuel pumps are a nightmare. I would suggest looking to see if Subaru sells DI engines in Brazil. If they do, sourcing a pump from there would be the best bet, since they use 100% Ethanol.

If Subaru doesn't, you'll have to find a pump from another vehicle. There are only a few suppliers of high pressure fuel pumps (Bosch, Denso, Delphi), so someone sells your pump or one close enough in Brazil (or even a flex fuel in the US).

If you cannot find a Subaru specific for ethanol, then find other makers with DI flex fuel vehicles, and get your hands on the pump. If the pump body looks similar, the chance is good the control strategy for the solenoid on the pump is the same.

And, yes Subaru does sell the Forester XT in Brazil.

http://www.subaru.com.br/forester-xt-turbo
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Old 06-19-2015, 08:29 PM   #31
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Just to be clear, this is the pump you are referring to, correct?



OP said his pump was failing. This is a mechanical issue, not a calibration one. The piston inside the pump is driven by the camshaft. This means the piston is moving all the time. Because it is moving all the time, the effects of poor lubrication of E85 are calibration independent. So, this is why you need a pump specifically designed to handle high ethanol content.

Here is a good description of how it works. It's kind of cheesy video, but the information is good. This should show you why the piston can seize to the bore with high ethanol content regardless of calibration.

https://www.youtube.com/watch?v=4M9BITr1zhg
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Old 06-19-2015, 08:32 PM   #32
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Originally Posted by MNC5 View Post
Bacon117: you sound so sure these issues are fuel pump & not tune related. Care to elaborate ? After running some E85 our WRX expressed its unhappiness by sputtering and stalling, surging. So did we ruin the fuel pump? Or did switching back to gas mask the symptoms. It runs fine on petrol but not so much on corn.
You have to log the pressure of the high pressure fuel rail. If it's really low (<~150psi), the pump might be seized.

If you switch back to gas, and it runs fine, the pump is still fine, it's something else in the calibration.
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Old 06-19-2015, 08:37 PM   #33
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Another cheesy video, but more information on the control of the solenoid. This control signal of the solenoid is what I calibrate at Ford.

https://www.youtube.com/watch?v=gvRuUm7Tzk0
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Old 06-19-2015, 10:14 PM   #34
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You have to log the pressure of the high pressure fuel rail. If it's really low (<~150psi), the pump might be seized.

If you switch back to gas, and it runs fine, the pump is still fine, it's something else in the calibration.
No $hit Sherlock. "Ethanol and high pressure fuel pumps are a nightmare" wondering what information you have to support this on the 15 WRX FA20.
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Old 06-20-2015, 09:55 AM   #35
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Yeah, I've just seen tuners on other vehicles crank up the Fuel Rail pressure, which causes premature HPFP failure. Then people blame the ethanol alone.

Sure, ethanol can strip the lubrication from the pump.

The tuning part I am talking about is how to ensure you can get enough injector pulse width without the need to increase fuel pressure.
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Old 06-20-2015, 11:04 PM   #36
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I don't know what to tell you. I know these pumps inside and out, it's my job. And what I know is that Ethanol is bad for certain HP pumps. You can just start running E85, but it's a risk that the pump will seize. Like all things, it might not. Even running E100, not all these pump seize.

Now, if the tuners are raising the pressure above the internal relief valve pressure, the relief valve will fail quickly, and the pump will not hold pressure. I don't know if they are doing that. The relief valve is only designed to relieve pressure from thermal expansion of the fuel in the rail when the car is off, they not designed to relieve commanded pressure. Just don't exceed the maximum stock rail pressure (rail pressure should be highest at high speed/load). This problem is independent of what fuel is being used.

Last edited by Bacon117; 06-20-2015 at 11:51 PM.
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Old 06-21-2015, 01:42 AM   #37
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This study had interesting results.

http://aprendeenlinea.udea.edu.co/re...ew/14157/12514

Versus this one

http://www.ein.org.pl/sites/default/...2006-04-13.pdf

I'm still in the "it's in the tune" camp. It could be a mechanical limit of supplying enough volume, but some are running E85 without experiencing a lean condition I believe. And as some had been adding lubricating oil to E85 and still had issues strengthens that opinion doesn't it?

It would be nice if anyone who has had their HPFP replaced could post up some pictures of the "Damage"
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Old 06-22-2015, 11:58 AM   #38
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I don't know what to tell you. I know these pumps inside and out, it's my job. And what I know is that Ethanol is bad for certain HP pumps. You can just start running E85, but it's a risk that the pump will seize. Like all things, it might not. Even running E100, not all these pump seize.

Now, if the tuners are raising the pressure above the internal relief valve pressure, the relief valve will fail quickly, and the pump will not hold pressure. I don't know if they are doing that. The relief valve is only designed to relieve pressure from thermal expansion of the fuel in the rail when the car is off, they not designed to relieve commanded pressure. Just don't exceed the maximum stock rail pressure (rail pressure should be highest at high speed/load). This problem is independent of what fuel is being used.
I agree with continuing to use the stock fuel rail pressure. There are other ways to make headroom for fuel delivery (earlier start of injection, retard ignition timing, etc.)
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Old 06-22-2015, 02:51 PM   #39
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Originally Posted by MNC5 View Post
This study had interesting results.

http://aprendeenlinea.udea.edu.co/re...ew/14157/12514

Versus this one

http://www.ein.org.pl/sites/default/...2006-04-13.pdf

I'm still in the "it's in the tune" camp. It could be a mechanical limit of supplying enough volume, but some are running E85 without experiencing a lean condition I believe. And as some had been adding lubricating oil to E85 and still had issues strengthens that opinion doesn't it?

It would be nice if anyone who has had their HPFP replaced could post up some pictures of the "Damage"
How does increasing the volume output of a camshaft driven piston pump affect the durability? It's not an electrical pump where you spin it faster to create more volume. A piston pump is displacing the same volume of fuel all the time, the solenoid being on or off determines if that volume being displaced is diverted to the high pressure rail or back to the low pressure line.


One of the things I assumed is that these pumps are seizing. That may not be accurate, I don't know how these are failing. So, I will concede that the pump failures the OP had may or may not be E85 related.


BUT, if the pumps are seizing, it's a good chance that it is related to E85. If the pumps simply stop building pressure, but are not siezed, the internal pressure relief valve has failed. This very likely calibration related, or simply a part failure. But a failed relief valve is not, so far as i've seen, related to the type of fuel used.
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Old 06-22-2015, 02:58 PM   #40
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Another thing to consider. If the pumps keep failing, are you sure the lift pump supply is not being exceeded? If the pressure to the high pressure pump is lowered a certain point, vapor can be created in the step chamber of the pump. If vapor is created here, the pump piston will lose lubrication and seize. This is because the pump piston relies on a very small amount of leakage (similar in principal to blow-by) and if that leakage is air, not liquid, the piston is no longer lubricated properly.
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Old 06-22-2015, 06:23 PM   #41
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Were you by any chance adding Lucas E85 additive to your tanks? It's suppose to remedy the poor lubrication of E85 and prevent this from happening.
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Old 06-22-2015, 09:18 PM   #42
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Another thing to consider. If the pumps keep failing, are you sure the lift pump supply is not being exceeded? If the pressure to the high pressure pump is lowered a certain point, vapor can be created in the step chamber of the pump. If vapor is created here, the pump piston will lose lubrication and seize. This is because the pump piston relies on a very small amount of leakage (similar in principal to blow-by) and if that leakage is air, not liquid, the piston is no longer lubricated properly.
Thanks for posting up the pictures and the "how it works" video. FWIW I couldn't find any ASTM standards for Lubricity of gasoline.

The following was sourced from a DAI Informational Document

American Automobile Manufacturers Association
(AAMA) has not deemed gasoline lubricity to be of
enough significance to include any type of lubricity
specification in their AAMA Gasoline Specification.
Nor is there any such requirement in ASTM
D 4814 Standard Specification for Automotive
Spark Ignition Engine Fuel.

And based on my Google Search Science the difference in friction between E10 to E85 doesn't look like enough to cause a failure mechanical failure so quickly. Let alone having it heal its self by going back to a E10 Premium fuel in our case. But there are studies that contradict each other, so you can't just say one side is right or wrong from what I've been able to read. But the difference in the results isn't large enough IMHO to result in a mechanical failure without something else as the underlying cause.

I suspect its the FP regulator portion of the tune is a big part of the problem. In our case the surging was out of hand until the car reached operating temp. After which it was only noticeable when cruising, not during acceleration or WOT.

So until I see the actual failed part or parts I'm doubtful E85 is solely at fault due to "Friction" or that "Friction" is the problem at all.
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Old 06-23-2015, 07:01 AM   #43
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Interesting. I just got a flex fuel map added to my tune the other day but have yet to fill up on E85 - nearest station is 40 minutes away.

About how many miles are you logging with E85 before you start seeing pump failure? Hopefully I won't be running it frequently enough to see any problems...

There's no way this is a lubrication issue (outside of that resulting from fuel starvation to the HPFP) - the time scales are much too short given the difference between E10 and E85. Either the pump can't handle the sustained additional fuel rail pressure (the more fuel that is forced into the high pressure fuel rail, raising the rail pressure, the greater the load on the pump, even if the total volume is the same) or the HPFP is being starved of fuel causing damage to the pump.

Do you have logs over the life of the pump? You should check if the HPFP solenoid pulse width gets longer over time. I have seen on another engine design that as the pump approached failure, it would gradually lose capacity and the ECU would constantly request more fuel rail pressure to compensate. This would hide the problem until the HPFP solenoid was at 100% and there still wasn't enough fuel. Perhaps the reason why E10 "fixes" the problem is because the pump's capacity it reduced where it can no longer support E85 but can still pump enough volume for E10.
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Old 07-03-2015, 07:52 AM   #44
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Anyone having idle stumble issues on cold start with the full E85 during the summer months? Just tuned for eE85 and now the car stumbles pretty good for about 20'seconds before smoothing out. Working with my tuner now to get it fixed.
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Old 07-04-2015, 12:53 AM   #45
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I've been driving my car hard and nothing but E80 and Lucas additive for 7,000+ miles and no issues. EcuTek Flex Fuel.... Not Cobb.
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Old 08-06-2015, 10:22 PM   #46
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I'm running E85 currently on my 15 WRX. Probably done about 750 miles on E85. I've noticed some surging lately, it feels like fuel cut. Is this what it feels like when the hpfp begins to fail?
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Old 08-06-2015, 11:57 PM   #47
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You're a larger idiot for thinking "blending" e85 and straight e85 is only worth a few whp.
You're a gigantic idiot for thinking anything above 40% ethanol adds any whp at all!!

The only reason for using E85 over ~E40 is the ready supply of the stuff and not having to bother mixing it with 93.
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Old 08-07-2015, 10:55 AM   #48
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Default E85 DI high pressure fuel pump

Latest problem for me is a cylinder misfire in #3. I've been told to run 3-4 max tanks of E85 then at least one tank of 93 to prevent any problems. The issue is intermittent but the misfire is bad enough where the car can't be driven. Not sure if this is fuel or spark related but the coil pack was swapped and its still a problem. Can anyone comment on the injectors and gunk build up. I'm wondering if the E cleaned out the tank causing my problem. Not sure if a fuel injector service will help or if just pulling the affected injector out and cleaning it.
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Old 08-07-2015, 11:45 AM   #49
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Latest problem for me is a cylinder misfire in #3. I've been told to run 3-4 max tanks of E85 then at least one tank of 93 to prevent any problems. The issue is intermittent but the misfire is bad enough where the car can't be driven. Not sure if this is fuel or spark related but the coil pack was swapped and its still a problem. Can anyone comment on the injectors and gunk build up. I'm wondering if the E cleaned out the tank causing my problem. Not sure if a fuel injector service will help or if just pulling the affected injector out and cleaning it.
Have you pulled the plug to look at it?
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Old 08-07-2015, 12:29 PM   #50
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Plug looked good. I took a pic of it but my phone won't let me upload it on the iPhone app.
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