I'm running a B16A3 with a Drag E-trim turbo kit, stock in-tank + Walboro inline fuel pumps (from the Drag setup), and saturated RC 750cc's. It was tuned with Hondata s300 at Church. To get it there, I had the stock injectors hooked up and a Vortech FMU on a stock ECU, but swapped the 750's in and disconnected the vacuum line from the FMU. The guy who tuned it said that the FMU was just running at a 1:1 since it was disconnected and I could just take it out later. Once it was fully-tuned (at 11psi), I drove it home. I have a Autometer air:fuel gauge (it's a POS I know) and all the way home it was in the green - at idle, at partial throttle, and under boost.

Here's the problem: I added a G-sport fuel rail and took out the FMU (which I didn't think would make a difference). When I started it up and let it idle, the AFR gauge was still green, but as soon as I drove it around the block, it went to amber in 1st and red in 2nd (leaning out) and so I coasted it back. However, when I initially got on it (to about 6-7 psi), I didn't feel any hesitation or hiccups. I swapped the stock fuel rail back on, and according to the gauge, it's still leaning out badly. Would putting the FMU back in (leaving the vacuum disconnected as it was when it was tuned) make any difference? Is the gauge too unreliable even though it was consistent on the drive home? Or do you think something unrelated to the rail/FMU might have just chosen this particular time to go out?

Any help would be appreciated. Thanks.

 

I wouldn't trust an Autometer A/F gauge for anything. Hook up a wideband and see what the A/F actually is.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by david@didrace.com &raquo;</TD></TR><TR><TD CLASS="quote">I wouldn't trust an Autometer A/F gauge for anything. Hook up a wideband and see what the A/F actually is.</TD></TR></TABLE>

I don't have one yet... but the A/F gauge was consistent for the whole two-hour drive home. Why would it change now? Anyone else have a similar problem?

 

narrowband, useless pretty much for F/I aspects. its like trying to measure with a scale thats not calibrated.

 

try running the fmu the way it was...see if it goes back to normal

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jockobo &raquo;</TD></TR><TR><TD CLASS="quote">try running the fmu the way it was...see if it goes back to normal</TD></TR></TABLE>

I was thinking about doing that... I'll definitely try it out today when I get out of work. With the stock fuel rail back on it and the FMU the way it was, it should be exactly the same way it was when it was tuned...

 

Any other suggestions?

 

first things first thru that autometer junk as far as the eye can see.... get your self a wideband and then go from there i bet your tune didnt change..

 

well if you installed a fuel rail and didn't have any type of regulator hooked up you'r not going to get a 1to1 ratio

 

you have to have atleast a stock regulator to bump up the fuel preassure 1to1 or the fmu.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by speedlabx2000 &raquo;</TD></TR><TR><TD CLASS="quote">well if you installed a fuel rail and didn't have any type of regulator hooked up you'r not going to get a 1to1 ratio</TD></TR></TABLE>

I'm running an AEM fuel pressure regulator. I had it on during the dyno as well.