im getting this hesitation around 3-6 vacuum, only around that range, runs fine at WOT. my O2 sensor is fine, and my map sensor voltage is at 4.6v. im running star stage 1, and missing link. i dont know what the problem is and it is really anoying. anyone have this problem, and know the fix?

oh ya, im running rich, my a/f gauge is around .96-.98 at wot. if that helps any ;) tia.

Is that o2 voltage reading at WOT in 1st, 2nd, 3rd, 4th, or 5th gear? It makes a difference because yer WOT voltage will drop as load increases in each gear. You should try to tune it so that yer around .93 at WOT in 3rd imo.

well i guess thats means theres no hope for me since i cant tune shit with the star stage 1 since i have the fmu. is the hesitation related to running too rich. im not sure what the voltage is in each gear, but i do know that it is always above .95.

Do you know what your fuel pressure is at? What is it at idle vacum, and at static (0 psi) ? You have stock injectors right?

I'm also thinking the initial hesitation is from running too rich because your MAP sensor seems to be OK; plus you got the missing link. Try to hook up a fuel pressure gauge to find out the static (idle) and WOT fuel pressures.

i have stock injectors, and i do not have a fuel pressure gauge. but if i get one, wouldnt it be pointless since i cant adjust anything?

Do you plan to get an adjustable FPR? Hooking up a fuel pressure will let you know exactly where you are, in terms of fuel pressure. I think it's easier to diagnose certain acceleration or hesitation problem(s) once you know what your base/wot fuel pressure is. At least it'll give you an idea as to where to look first; it gives you an idea if you should look for something in the fuel system, vacuum, or ignition.

For some obvious reasons, if there is any problem, I think fuel problems need immediate attention, especially when you're turbocharged. So, I pay a lot of attention to it, along with ignition.

hmmm....i guess i should look into getting the sfmu. but when i went turbo i bought regular ngk spark plugs. i didnt buy the 1 range colder plugs. would this cause the problem? also i gapped the plugs at .32 . what should the gap be? also anyone have the part number for the ngk spark plugs 1 range colder? tia.

Dude listen up.

Buy NGK BKR7E-11 plugs NGK Stock number is 1283

Gap them to .035 and change them every 3K miles with your oil.

Your hesitation is totally normal. I have been getting that for the entire time I have had the Star Kit on. I still use the VC1 instead and the voltage is just fine.

I try and stay out of that range in vacuum when I drive. It is very annoying if I am going 75mph with the AC on. It seems to stay in that range and hesitate unless I go above or below. When the cruise is on, it is less noticeable or not as harsh in that exact range.

I personally think the vortech fmu is starting to raise fuel pressure and the initial extra fuel causes the hesitation until the short term fuel trims can adjust. It only takes a milisecond, but when I initially come into boost at wide open throttle, there is a puff of black smoke that comes out of my tail pipe. I also do not get this hesitation if I slowly push down on the throttle and go past this 3-6 vacuum. This only happens when trying to drive between these numbers.

So live with it and be happy, or find another way to get more fuel without an fmu. I have adjusted and all is great. It might not be a problem with a smaller disc/ring and bigger injectors. I use 30LB and with say 48LB injectors/3:1 disc/ring, the hesitation could be almost nonexsistent. Maybe Dino or others that have been there or done that will fire back.

BTW: I also did the fuel pump rewire(10 guage) to the battery. This will most likely add to the problem. Well worth the added protection it provides though......don't ya think?

Good luck dude

thanks for the reply. i apreciate ur help.