How does a FMU recalibrator work?

Alvin@pcmforless.com
07-05-2003, 12:24 AM
I've got way to much fuel with my FMU.. Its going max rich at 4000 rpm and not pulling beyond that because of it (I guess)


Has anyone looked at the recalibration kits Vortech sells? I hate to wait a week for a few washers and pay $40 for it

Camaro_SS/R
07-05-2003, 03:16 AM
Originally posted by ROOSTER93V8
I've got way to much fuel with my FMU.. Its going max rich at 4000 rpm and not pulling beyond that because of it (I guess)

Don't quess, you really show know what your A/F ratio is especially with a mail order tune and supercharged, even though Brian is really good. Also, how do you know which recalibration kit to buy and you will need the dyno data for Brian to retune. :)


Originally posted by ROOSTER93V8
Has anyone looked at the recalibration kits Vortech sells? I hate to wait a week for a few washers and pay $40 for it

Two years ago, I had bought the 6:1 and 4:1 recalibration kits. It is just a round plastic sheet and a metal washer. You just have to open up the FMU and put those in. They work fine, not the ideal instrument but does it's job well and cheap. I don't use the FMU anymore since I have the 72#/hr.

good luck

96 WS6
07-05-2003, 04:22 AM
Hugh, Rooster does the chips for PCMFORLESS, so it's not really a mail order tune =)

Alvin@pcmforless.com
07-05-2003, 09:54 AM
Yeah, I'll tell you that a centrifical is gravy compared to tuning this thing. tuning a forced induction 1 bar system isn't as easy as a MAF car by any means.

Its almost like starting from scratch, everything has to be redone and big time...

I'm sure that the thing is going to rich, its choking the motor too much.. Problem is I bought a used FMU with this project and have no idea what ratio it turely is.

I've got to use a FMU with this car, its 1 bar speed density

Mikael
07-05-2003, 12:26 PM
You're sure the high fuel pressure isn't causing the injectors to lock up?

The ATI FMUs use a bleeder screw where the vacum hose hooks up, to bleed off boost pressure. This may work for you, although you'll need to make sure the boost guage and fmu are on different vacum sources.

Alvin@pcmforless.com
07-05-2003, 02:23 PM
I think thats why they use a boost restrictor and a bleed valve to prevent a ton of boost from leaving the manifold or vaccum lines.

A check valve on the FMU signal should prevent probelms with boost gauge/FMU mix up

Alvin@pcmforless.com
07-06-2003, 01:26 AM
Fixed it for $6

you know... I'm really getting tired of building for the same project.. its time for something else!

http://www.thirdgen.org/techbb2/showthread.php?s=&postid=1385886#post1385886