So I only drive the stang usually once or twice a week, after the tune and recent mods I have noticed that when starting it actually seems like the car is not receiving enough fuel. It's not a battery/starter or alternator issue, its more like the car turns over and sounds like it wants to stall. This only happens If I start it after letting sit for an hour plus. After the tune was finished, the tuner told me that I am just about at max for my fuel pump, wondering if this has anything to do with the start issue?

 

The pump being maxed out is at WOT only. If you have problems with fuel pressure at idle you will not be able to drive at all.

What mods and tune? Why would you look at fuel pump or battery when you answered your question right there. If it started out of the blue I would look at all sorts of things, but like you said, "after the tune and recent mods..." i wouldn't look much further than that. It could be that your car is just relearning to idle after installing the new tune. My car takes about 10-12 cycles before it tends to want to idle correctly sometimes. But it kind of sounds like your open loop fueling tables are off a bit. What did your tuner say when you contacted them?

 

Custom tune, recent mods: O/R mid pipe, axle back, smaller S/C'er pulley, and a few others that wouldn't cause the issue (Killer Chiller/gears). The car was fine for the first couple days, then I parked it for about a week and the next time I tried to start it was hesitant (felt as though it was stalling). I figured it was due to sitting for a week but after driving it for awhile, parking and coming back out to start it again same problem. Since then, it's been troublesome every time I let it sit for an hour or so. Tuner claims its a coincidence and that he "never touched crank fuel" but can make an adjustment.

 

I had the same issues with my car, but only after it sat overnight.. Once the engine reached normal operating temps, the cold start/hesitation issues went away..

I found out that it was in the tune I was running at the time in which the cold start issues were related from my open loop/fueling tables being off a bit..

Since upgrading to Brenspeed tunes, I haven't run across any cold start issues since then..

 

Appreciate it ^ When I get some free time I'm going to have my tuner look it over.

 

It's been a while but I had something similar and it had to do with the fuel trim levels that are mapped into the tune at startup. The tuner explained to me, and again it's been awhile so I'm going on distant memory, that the way the cars computer reads the fuel at start up/idle on a cold engine isn't really ever touched by tuners. The car in its original programming will go off base values until the engine is warm and then take readings. With all the changes I had the base values didn't work anymore and he did something to make it start reading the information sooner.

I think.