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General Adjustable fuel regulator

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Steve92talon

Proven Member
156
21
Jul 3, 2019
Fernie, BC_Canada
I Installed my adjustable regulator but the fuel rail connection was wrong so I just moved the vacuum line to the adjustable one and left the stock one on the rail. I had my pressure set to 43psi hose off but it still gets lean in high rpm. Is my regulator doing anything with the stock one still on the rail?
 
No. The one on the end of the rail is doing it all right now. When you go to and adjustable unit, that end of the fuel rail becomes open and a hose fitting, usually a 6an, will go there and lead to the adjustable regulator, which then is the end of the line and you can adjust it then.
If it leans out at high RPM, you could have a fuel pump that just can't keep up. What pump are you running in the car?
 
I Installed my adjustable regulator but the fuel rail connection was wrong so I just moved the vacuum line to the adjustable one and left the stock one on the rail. I had my pressure set to 43psi hose off but it still gets lean in high rpm. Is my regulator doing anything with the stock one still on the rail?
If you leave the stock regulator on the rail how are you even moving fuel through the new one? Pics please. This doesn't make any sense at all.
 
I think what he is saying is that the outlet of the stock regulator is feeding the afpr. But he also states he moved the vacuum line to the afpr and left the stock one with no boost source. His high rpm lean condition is likely caused by the stock regulator not raising fuel pressure with the boost pressure, as it has no signal, so the car is going lean. The stock regulator is still regulating while on the rail. It needs to be changed for a fitting to allow the afpr do its job.
 
Yes there in series till i find the right fitting. The stock one goes into the adjustable one. i only lean out in the first 3 gears. On a highway pull in 4th and 5th it's good at 11 ish afr I was thinking higher psi increase the fuel but is that incorrect
 
I think what he is saying is that the outlet of the stock regulator is feeding the afpr.
See I was thinking the adjustable one would keep my fuel pressure higher so the stock regulator is just open and by passing. I can run a vacuum to both regulators if that would do anything.

What pump are you running in the car?
Probably a stock one. I haven't pulled anything apart but it's a stock set of injectors too I believe. They're blue caps
 
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See I was thinking the adjustable one would keep my fuel pressure higher so the stock regulator is just open and by passing. I can run a vaccum to both regulators if that would do anything.

The problem is the stock regulator ahead of the afpr creates a large pressure drop across itself. So the afpr doesn't have much pressure ahead of it to control around. It isn't really seeing pump pressure at its inlet, it's seeing factory regulator output pressure.

Whether or not you can connect vacuum to both of the regulators is an interesting thought. I am not sure how that would work dynamically but my expectation is the factory regulator would run out of adjustment depending on your set boost level. The other issue you have is if you have a fuel pump of a decent size its gonna outflow the factory regulator and cause other weird fuel control issues. Instead of fighting a system that can't be easily characterized I'd swap the fitting and use the adjustable regulator. The fittings required to make this work correctly are available for pretty cheap from many of the vendors that support this site. I've linked a couple below.

https://stmtuned.com/collections/1g...tm-6an-fuel-rail-fitting-frf-6l-1g-dsm-outlet

https://www.extremepsi.com/store/Fuel-Rail-Adapters/


If it makes sense for your situation a full install kit may be helpful.

https://www.extremepsi.com/store/Fu...irewall-Install-Mitsubishi-Eclipse-90-99.html
 
I will look up a fitting and just take it easy for now at the same 16lbs it's set at for boost.
 
AT LEAST put the vacuum line back on the stock regulator.
 
I have a wide band car runs fine at 16 if I'm not driving it stupid. On the highway it wont go under 11.5 it just the fast rpm spikes in 123 it leans out on the top end of rpm. At 10psi its pig rich in every gear. Hoping for 20psi with the regulator hooked up right
 
My thinking was the adjustable one is set higher then the stock one so the stock one should just default to wide open cause the fuel pressure will always be higher so it wont ever close. Just temporarily till I pull it totally out
 
Nope. The regulator on the end of the rail is the control for your fuel pressure at the current time. It MUST rise at a 1:1 rate with boost or you will not have enough fuel for the extra air that is coming in under boost. If it doesn't rise with boost you WILL run lean and can possibly melt your pistons and torch valves. Just trying to explain what the possible outcomes for you could be, so be careful.
 
Ok? I'm not running a AN line anywhere in my car yet
most of your goor afpr's are going to run an type fittings. a guy can also get a 6an to 3/8 hose barb adapter if youre not able to run all an stuff yet. but it would be best to get the stock one off asap.
 
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Too bad I finished a 600km trip yesterday no blown motor working just fine.
 
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