I was talking to my buddy at work today, he has a 400whp turbo neon, not an SRT, the old body style, 95-00 i think it is. He converted his fuel system to a return system using an aeromotive rail.

I know they don't sell a rail for us, but they do have rail blanks, how much machining is involved in machining one for our cars.

 

Just so you guys know...I found out today on the Ecotec forum that it is possible to up the fuel pressure on the LSJ thereby avoiding the problem of not enough fuel during high demand situations. We could either run a second inline pump or a different fuel pump altogether.

This would allow us to run smaller injectors as well which would make tuning easier by having more control over exact amounts of fuel. All that has to be done is to modify the Fuel pressure (Kpa) to Voltage table while tuning so that the computer will interpret the 02 sensor signal as being normal rather than trying to pull voltage to the fuel pump or changing injector pulse width.

Changing to a return system is probably the best option, but this is another option that is possibly more simple and maybe cost effective. The tuning would be minimal and the fuel pump wouldn't be too much especially if you just wanted to run a little more pressure with an inline pump.

Just thought I would let you guys know. This is definately a viable option to doing away with the restraints of the fuel system and it's byproduct of a blown 4th cylinder. Let me know what you guys think.

 

Smart man, nice write up Adam!

 

what ill effects would there be running an inline pump in addition to the in-tank pump, i remember on the J-body forums guys were burning out the in-tank one because the inline wanted to draw more than the in-tank was providing.

 

Yeah...I could see that being an issue if you ran too big of a pump. You would also need a controller for the inline pump which would only turn it on in bursts during WOT. I believe there is also a way to give the inline pump it's own supply line from the tank so that it would be pumping fresh fuel into the main fuel line and simply adding pressure and flow.

The best way would probably be to use a larger main fuel pump...but that of course would not be as easy.

 

well what options exist for in tank fuel pumps for us? What does the stock pump flow?

 

if the 5th injector setup is so unpredictable, how come companies like Alpine are using it?

 

Here's a couple parts you can use....
Fuel pump.
http://www.holley.com/12-920.asp
Regulator.
http://www.holley.com/512-504-5.asp
or.
http://www.holley.com/512-505.asp


These should give more then enough fuel to your hungry little SC 2.0's

Its the easiest set up.

 

Use a 2001-2002 Ecotec fuel rail. Its exactly the same as ours but with a return fitting tapped into the top of the rail (where that molded circle is). Holley makes an in tank 255lph fuel pump that will drop in place of the stocker iirc its made for mid nineties V6 buick/pontiac/chevy applications, just remember to remove the in tank regulator as well (real easy, just remove the stainless steel bracket and valve you see). Also you'll need a new fuel filter, one with one inlet and only one outlet. The return line needs to run from the fuel rail back to the old fuel filters return line.

 

Mine stared spraying fuel while the car would crank, filled everything with fuel, car hasent been the same since. When garret releases the full bolt on tuned kit I will swap to there tuning solution

 

so which way would be the best way to fix this issue, just an inline pump or the description WITT gave? I would like to complete this option asap before it goes back on the dyno to get tuned again

 

You also have to take into account that only 1 injectors is firing at a time. So being farest from the fuel inlet starts makeing less sense.

If you used a Rising Rate FPR you could just adapt the inj flow vs vac table to match the new flow rates...

 

zinner, can you elaborate on that a smidge, im not sure I follow

Witt, is this the pump you were referencing: http://www.holley.com/12-903.asp

 

At 80% duty cycle that would put three open at the same time. 100% and they're all open all the time.

Its similar to that. You have to take the old pump in and compare it to new pumps. It has to be the same height most importantly.

 

Update:

At the Ecotecforum there is a member who is trying to tap the rail from both sides, which actually is a way of controlling the problem. He is going to let me know how it goes and I will update this thread.

I know a return system has many benefits, but staying with our stock fuel system would be cheaper and if we can assure that the rail definately has common pressure then tuning would be more effective as the reading that the 02 picks up will be more accurate as all of the cylinders would actually be functioning together. This would make the adjustments made by the ECU more precise.

This fix will be monitored and before it is said that it will work it will be proven. At that point there will be solid proof of this route fixing the issue.

This post applies directly to this. FMU style fuel management is okay, but if we can assure solid fuel pressure it will be easier to tune using the above.

 

Couldn't you just split the incoming line into both ends fairly easily? Or if you really wanted to be sure, 3 lines, with an extra tap running into the middle of the rail. If you did it with braided line, it would look pretty cool too. Would assure constant pressure across the 4 injectors I would think.

 

thats actually a pretty interesting fix, doesnt sound too crazy costly either... eagerly watching for results....

 

It definately seems like this would be the case. A member named NoRemorse is attempting this and says he will update his progress as he goes. No matter what, there will be a solution that exists which will be cheaper and easier than converting to a return system, it is just unknown exactly what that solution is right this second. At least we know testing has ensued!

 

why would a return system be so expensive, couldn't you just tap a fitting into the current fuel rail and run a return line, ad a regulator and a new filter maybe an inline fuel pump and it should work. doesn't sound that expensive either. i know our fuel rails have a perfect spot for tapping a fitting if you pull off the injector cover you'll see exactly what i mean.

 

I know I mentioned it once, but you can use an 01-02 ecotec fuel rail. I bought one from ebay for less than 20 bucks and will keep you from chopping up your stocker.

 

thats exactly what i was talking about right there, our fuel rails are the same except the return line hasn't been tapped for a fitting yet.

 

Why not unbolt the "dampner" cap on the closed end of the rail and tap that or make another cap with a fitting for the return line?

 

01-02 rail would bolt right on, same injectors everything? then how do you go about disabling the in tank regulator?

also, if you tap both ends of the rail as discussed above, what potential problems would there be with the pump not flowing enough fuel..

would it be a wise idea to just upgrade our in tank pumps anyway once we start pushing gobs and gobs of power? What tuning changes would need to take place to accomodate the new pump

 

subscribing

 

Its the same rail as you can see, just tapped at the top. I got the idea after seeing my father''s '02 Cavie LS Sport with the same rail. The in tank regulator has to be removed and the line that runs to it from the fuel filter will have to be connected to the return line of the fuel rail. Attached is a pic of the regulator I removed from an extra unit djt81185 purchased for us to build and install.