please help with fuel problems

[alanw6]

Hello,

I haven't had any luck on other forums with this recent problem, and was hoping I could find some help here.

I just added a walbro 255 lph intank pump and aeromotive afpr to my mustang. It is a stock-motor 92 5.0 with a v-2 s-trim kit on it. Other mods are 6al, full exhaust, and powerpipe. The rest of the car is stock.

everything ran fine until the new intank pump and regulator. Now, cruising in traffic, if I give it part throttle the fuel pressure drops from around 38 to almost 30, then snaps back to 40 very quickly. This takes about 1.5 seconds in total, and you can feel the power surge when the pressure corrects.

Second half of the problem: I'm using the supplied FMU with the stock 19lb injectors. Before the new mods, the pressure was rock steady around 36 and would go to 75-80 under boost at WOT. Now, the gauge pegs at 100, and it happens fast!

does anyone know what I'm dealing with here? I'm thinking about pulling the t-rex out, but so many people use this combo that there must be something else wrong.

Sorry for the long post, hope someone can help me out.

thanks in advance,

Alan

[s-trimmed302]

Alan,

that combo with the stock 19# injectors would scare me..You really need to Go up in size of Injectors to at least 24s or 30s..Preferably 30s at the least.. I would say that your 19s are going Static pretty fast with that FMU..

My advise would be go with a set of 30s, Pro-M 80mm Shorty MAF, and a Much smaller Calibration disk in the FMU..This will be a much Safer combo..

Jeff