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Discussion Starter · #1 ·
I've been having this on going issue with my tuner on my car and we, along with the guys from the shop, can't figure it out. I have a 2004 sti. It's running 2000cc ID injectors, I have 450walbro pump, and a tail fpr. The car is running e85 and I'm making roughly 520whp. Here's the problem.. it has a horrible start up, it can take up to four attempts to start the car, even with priming, and once it gets going it's a bit rough (probably due to all the fuel build up from cranking). Once I shut the car off the fpr will show pressure drop to about 5psi from the 40 it was at in a matter of seconds and then to 0 with in the minute. I've changed the fuel pump again, attatched a different (new) fpr, added a inline fuel filter and eliminated the one on the in tank system, replaced the fuel control module and it's still having this issue. I'm out of ideas at this point, any help would be greatly appreciated and thanks in advance
 

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I would try hard wiring the fuel pump and see if that makes a difference. The wiring to the factory fuel pump controller isn't really enough for a Walbro 450. I might also try running ID1700s and see if that helps. It's not always easy to dial in injector latency low enough for start/idle on the 2000s.
 

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Who's your tuner?
 

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Discussion Starter · #4 ·
I would try hard wiring the fuel pump and see if that makes a difference. The wiring to the factory fuel pump controller isn't really enough for a Walbro 450. I might also try running ID1700s and see if that helps. It's not always easy to dial in injector latency low enough for start/idle on the 2000s.
I'll bring that up to my guys then. I'm still learning a lot about subarus's and I've been working and learning on this thing for almost 2 years now. We did replace the fuel controller and we know it's not that issue but I didn't think what you said could of been a possibility. Apparently not too many people go 2000cc ? I may down grade if I can't get it right..
 

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Discussion Starter · #5 ·
Who's your tuner?
I rather not bring up his name because I respect the work he does and this is one of those things that can be tough to get right from what I keep hearing. And as the last guy who commented, it may not be to much of a tune situation.
 

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I rather not bring up his name because I respect the work he does and this is one of those things that can be tough to get right from what I keep hearing. And as the last guy who commented, it may not be to much of a tune situation.
I understand. Do you have full rights to the map and what method is your tuner using to remap your ECU?

The reason why I ask is that sometimes people forget to scale the cranking injector IPW by the size of the new injector. These tables look like this (OEM map for 2004 STI)



There are also ECT tables that may explain difficulty in cold vs warm starts.
 

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I'd go ahead and put the sock back on the in tank pump.. it will help keep your inline filter from getting clogged quickly.


Maybe just pop in some stock injectors (or whatever is on hand), adjust the scaling and latency, and see if that makes a difference.
 

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Discussion Starter · #8 ·
I understand. Do you have full rights to the map and what method is your tuner using to remap your ECU?

The reason why I ask is that sometimes people forget to scale the cranking injector IPW by the size of the new injector. These tables look like this (OEM map for 2004 STI)



There are also ECT tables that may explain difficulty in cold vs warm starts.[/QUOTE]

Ya he said Rhode are all things that he has done. He's adjusted it a few times and got nothing that made the difference needed, sadly. :'(
 

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Discussion Starter · #9 ·
I'd go ahead and put the sock back on the in tank pump.. it will help keep your inline filter from getting clogged quickly.


Maybe just pop in some stock injectors (or whatever is on hand), adjust the scaling and latency, and see if that makes a difference.
Ya, I kept the sock on but just made it a direct hose line where the oem filter was. From my understanding, that filter can restrict the amount of fuel that pump is trying to push up. And I'd have to buy new injectors because I don't have any other ones currently. I was really hoping to get this solved versus resorting back
 

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H3RK said:
Ya he said Rhode are all things that he has done. He's adjusted it a few times and got nothing that made the difference needed, sadly. :'(
H3RK said:
I rather not bring up his name because I respect the work he does and this is one of those things that can be tough to get right from what I keep hearing.
Are they familiar with Subarus? Someone can be a fantastic GM tuner, but a piss poor Subaru tuner. Nothing against them, our cars have some quirks that make specialists worth their weight.
 

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Discussion Starter · #11 ·
Are they familiar with Subarus? Someone can be a fantastic GM tuner, but a piss poor Subaru tuner. Nothing against them, our cars have some quirks that make specialists worth their weight.[/QUOTE]

Ya, he's actually pretty damn good with subies, gtr's, gti/r, st's/rs and many others. He saying he's done many similar tunes along the line of mine with 2k injectors and has never had this issue, which leads me to believe it can be something else maybe?
 

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H3RK said:
Ya, he's actually pretty damn good with subies, gtr's, gti/r, st's/rs and many others. He saying he's done many similar tunes along the line of mine with 2k injectors and has never had this issue, which leads me to believe it can be something else maybe?
Who supplied the parts used in the build? Did you buy the parts from them?
 

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Discussion Starter · #13 ·
[/QUOTE]

Who supplied the parts used in the build? Did you buy the parts from them?[/QUOTE]

That's where I may have messed up..the fuel lines, fpr, fuel rails, and injectors where off of another buddies old build. Everything else was brand new. But that's why we connected a different regulator another friend had(new one) to see what it does and still did the same thing..dropped pressure immediately and horrible start up after a few minutes or less of sitting. I hear rumor that some regulators maybe have different ratings, per say, on how they hold fuel pressure in the lines and what not. But ill let you keep up with the ideas because I'm hoping at some point one of these things can be it lol
 
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