How many miles are on the car? How many miles on the fule pump? Another guy, local, was running only 11 to 12psi on a pettit unlimited, but getting fuel cut at various rpms, changed the fuel filter, and it turned out it was his fuel sock was clogged and dirty. Took it out, cleaned it since you could tell it was being sucked in towards the pump due to the poor flow, it would restrict fuel going into the system. Somthing to check atleast.

Tim

 

I got 1200 CC injectors, HF Fuel pump and MP, I ran with .88 boost and had no problems. I will know more as I get more runs. So far so good.

 

Do yourself a favor: invest in a Datalogit. Then you can tell exactly what is going on in your runs with boost, and INJ duty, and knock, etc.

Do your car a huge favor and get a DIY Wideband O2 kit for your car and hook it up to your Datalogit. Then you'll see how lean you're running when you hit those "cold maps."

Check out this thread to see a graphed log of a dyno run.

Now imagine being able to pull that kind of data out of a run (and know what to do with it!)

Good luck!

 

My car was tuned by Rx7fasion. He used a wideband. I will put my car on a dyno and see how its doing. Thanks for the info!

 

I am having the exact same problem. I recently had my engine rebuilt and ported. I have dp, mp, cb, intake and the rest of the fun stuff. Upon rebuild, I installed a nippondenso fuel pump and brand new fuel filter. I'm sure that the problem is in the boost settings and is not an ignition/fuel issue. Winter in Florida is rough because it can be 50 one day and 90 the next so I am in the same boat. I am interested to find out if the profec is going to cure your problem. If you find anything, please pm me! Thanks

 

I found the problem is related to the power FC settings and the cold/density of the air. You may having setting 1 that works now and in an hour it doesn't work. there are 2 ways to fix this. 1st is not shifting at redline in 2nd gear. If you shift at 6K you will not as likely get the fuel cut. Don't ask me why, its retarted.

To give an idea of what usually works for me...The power fc will cut fuel if you spike .25 above your desired boost. Keep in mind it will NOT correctly show the spike on power FC. When I dyno tuned my car it spiked to 15 but the power fc did not register the spike. Anyway...

if you have your settings like this...

.80 78
.80 68

You are telling the power FC "run 11.76" lbs of boost. That is all fine, but if you spike to 14.7 or more you will hit a fuel cut. a 15 psi spike is easy with this car. On the other hand, if you change the settings like this...

.80 .68
.85 .58

You will be far less likely to hit it, cause .85 is 12.49 lbs of boost and you will have to spike to 15.6 to hit a fuel cut. I found with the settings above I hit a fuel cut rarely. if you find you hit a fuel cut you can slowly turn down the duty cycle and that will solve the problem.

for me my racing settings are going to be...

.90 .68
.90 .58

BTW..take all of this with the understanding that my research and 50 or so runs I have done at the track have led to these findings. You may or may not agree, but i'm convinced.

EDIT: I sold my profec B to rynberg, decided I don't need it.