z71tahoe

I was told that my 2002 5.3 (flex fuel motor) has a problem with the fuel supply when supercharged (ATI Kit). Apparently the regulator only allows for 40pounds of fuel at idle, and I should have 60. (My fuel guage has confimed the 40)

I was told that I needed to purchase a fuel rail assembly and regulator from a non flex-fuel vehicle (Whipple).

Does anyone think this will work? I priced everything out (<$500) but I do not want to to have buy new rails if I just need the regulator.

I have a few pics of my truck on the web Z71 Supercharged

GMC SKI

hey Did that tube that you have come with the ATI kit ?where did you get it from?
I'm still using the stock tube ..that keeps blowing off
I too am having fuel supply problems
what's the inline pump rated at that comes with the kit ?
Have you dynoed the truck yet ?
what's your air fuel ratio at ?

oxidizr

iTrader: (4)

I have one brand new 6.0 fuel rail-crossover tube set / regulator (adjustable OEM) / and 5.3L injectors and one used 5.3L fuel rail-crossover tube set / another 5.3L regulator (adjustable OEM) I may be willing to part with depending on how my custom rails test with the 8.1L injectors. Take a picture of your rails and post or e-mail...I curious to see how they differ.

Richard

BTW- does your truck have an adjustable and/or vacuum boost style regulator?

RW

<small>[ May 26, 2002, 08:45 PM: Message edited by: oxidizr ]</small>

parish8

iTrader: (6)

oxidizer.. why the new fuel rails? wont the 8.1 injectors work with the stock rails?

z71tahoe

My problem is finaly figured out. I am definitely not getting enough fuel. If i floor the truck from a stop the FMU keeps up with the demand and the truck never runs lean- BUT when driving normal and suddenly stepping on it the FMU will not keep up when the tranny drops down a gear it runs lean for a second but by then its to late- How can I get my FMU to kick in early? Is there a way to make my stock regulator allow more fuel than 40? I am sure i should have 60 at idle.

GMC SKI - I think you are referring to my K&N intake tube. Even that had to be reinforced to hold up to the boost- but I have no problems with tubing. The inline pump that came from ATI gives me at least 100psi to the rails when my truck hits 8psi boost. I have not dynoed the truck yet but it goes in for the exhaust next week and on the dyno june 4th-

oxidizr - I would be interested in purchasing your rails/regulator if that is what I need to do. I really want to have more fuel pressure at idle- I will take a picture of my rails tommorrow and post on my page.

oxidizr

iTrader: (4)

parish8:

Yes... but the factory crossover is small, the regulator is very restrictive and the factory rails have a restrictor/divider which slows fuel delivery (was offered by factory for more even pressure along the entire rail.) With the new pump and extruded rails I don't perceive even delivery will be as important as volume. Yes the 8.1's are interchangeable.

Ben Tickner
Once you post and I can identify the differences I will part with some of my spare goodies. Check to see if your regulator on the return line of the rail has a #10 security torx bit...if it does you can adjust the idle pressure...if it is the same as the non-FF regulator, I have an extra OE adjustable regulator you can swap in its place...just let me know.

Richard

Neil 6.0

Sorry, I can't help with your blower problems, But I just wanted to say that is one BAD *** Tahoe! <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

GMC SKI

What is everybody's fuel preasure at idle ?
how much can i get out of the adjustable regulator.
if i crank it up it will give me more presure and fuel at all rpms?

stephenspann27

iTrader: (1)

Back from the dead!
I have a 2002 Z-71 Tahoe that is Flex Fuel. I am having problems with pinging under hard acceleration. I checked the FP and when I saw that I only had 42PSI I thought the pump must need to be replaced. I replaced the pump and the pressure is the same. Now I know that the specs are different for flex fuel tahoes.. bummer. Even when I unplug my FPR the pressure doesn't go over 52 PSI so I"m guess just swapping the FPR won't raise the pressure much.