AFPR/850cc injectors/Walboro 255hp now stuttering

[Ravenous]

My car was getting low boost knock, 13-20 counts at around 5psi(14b mbc'd at 16psi). I believe the problem was that the base timing was off, that has been fixed. It was a little over 10 degrees advanced, not sure how that happened but it is fixed now. I am now reading 5 base with the terminal grounded and approx 7-8 at idle with ecu compensation. I also installed new FIC 850cc injectors, walboro 255hp fuel pump, and an Aeromotive fpr. Base fuel Pressure is approx 37psi with the vacuum line disconnected. I have compensated for the bigger injectors using tunerproRT and an ostrich romulator. They are set at 850cc compensation with 330us added to the deadtime across the board. The car now idles amazingly smooth and has a little growl to it, however when accelerating the car hesitates a bit. Boost is now maxing out at about 10psi. There is no knock at all, logger or on the knock gauge (boost gauge code altered on ostrich). To me it sounds like a boost leak, and I will test for that, but there is no smoke out the exhaust and nothing audible. Not to mention I didn't disconnect any intercooler hoses or remove any vacuum lines other than the fuel pressure line. Does anybody have any idea what this problem could be? It ran pretty good before even if the timing was way off? I will try to get some logs, I am using TMO but am going to try to get mmcd so I can log g/rev as well.

Any input positive or negative is greatly appreciated.
Thanks,
Chris

 

[winterftbl]

Are you sure you have a good tune?

 

[Captain D]

I had a hesitation problem that turned out to be pcv valve that leaked under boost. I installed a check valve between the pcv valve and the manifold and that fixed the problem. I still use the same pcv valve.

 

[Ravenous]

Hey all thanks for the replies... my tune is probably less than desirable. I am still fiddling with the palm emulator so I can log with mmcd. Right now I am using tmo which doesn't show g-rev so I can't see where I am on the fuel/timing maps. Tuning with the ostrich is a learning experience. I did relieve some of the hesitation by setting the injectors at 920cc and increasing the fuel pressure to 43psi.

I used the formual 450cc/850cc=.5294 then (.5294*74)*.93=36d which is 24hex which equates to the 920cc.

There is still some stumble but I believe it can be fixed with some fine tuning. I don't have a compressor (beyond a 12 volt tire compressor) to do the boost leak test, so until I can borrow one I have to assume the leaks (which I am sure there are) are small. I will see what I can figure out this weekend as far as boost leaks are concerned as I know that is really the first thing I should do.

The thing I find wierd is that the hesitation seems to be right before boost starts to hit, say 0-4psi then the boost shoots up but the car feels like something is restricting it (probably a boost leak or poorly calibrated timing maps)