so here is my problem and yes i have searched.

I have a 96 talon esi manual tranny. My mods are as follows:

Custom ht18s
gss342 wally 255hp
missing link
vortech 12:1 fmu
boost a/f gauge

i have had this problem from day one with my turbo setup. If i build over two psi the a/f goes way lean, at around 4psiit falls on its face and starts to back fire.

at first i though it was the missing link so i took it off and blew in the bottom of it and was unable to blow trough it. I reistalled the map sensor with out the missing link and the performance is exactly the same.

i have double checked all of my items, i have a small boost leak at the BOV. The fmu is plumbed down stream of the stock FPR with the line to the tank coming out of the center fitting. I am at a complete loss and no one on another site was able to help me.

What is your Fuel pressure?

Is your FMU before or after your fuel rail?

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2012 2500HD LML

fuel pressure i apprx 45psi

fmu is between fpr and fuel tank.

http://www.2gnt.com/?d=SFMU_Installation_Diagram

Read the installation diagrams.

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2012 2500HD LML

i have a returnless system.

I realize that.

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2012 2500HD LML

so you are telling me that i have to make a return from the rail?

Manual for FMU: http://www.vortechsuperchargers.com/pdf/manuals/superfmuim.pdf

More links:

http://www.dsmtuners.com/forums/420a-turbo-conversion/188926-fmu-install-s.html

http://www.google.com/search?q=how%20to%20install%20fmu&ie=utf-8&oe=utf-8

There is plenty of information regarding the install of an FMU on various platforms.

Did you read the first link I gave you regarding its installation? The picture there accurately shows how it should be plumbed in your system.

If you searched, you would have found the post two down from yours:

http://forums.2gnt.com/dcboard.php?az=show_topic&forum=8&topic_id=108561&mesg_id=108561&page=&topic_page=3

That completely describes how the FMU is supposed to be plumbed.

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2012 2500HD LML

thats all for the sfmu, which i dont have, as far as the dsm tuners site that is how i have it installed.

and just so you know i read that through, and it not my problem thx.