Ok so here is the deal, I ATTEMPTED to install a 2nd Ford GT pump into my stock GT basket. WELL it fit, but it wasnt going to be safe at all (re wires grounding on clamps). So we pulled the 2nd pump out and just left what I had been running in place (Single Ford GT pump). Used the Gates S30R10 3/8s hose I bought inplace of the stock junk, and also elimintaed my PPRV (seems different then stock cobra PPRV). So it goes from the pump to an immediate copper elbo to make the sharp bend and then loups around to the outlet. Everything is clamped.
So I fire up the car and she fires right up. Go to town and get gas. Running like normal. I pull out of the gas station and the car starts missing! Look at my fuel pressure and its jumping from 25PSI to 50PSI at the pump (rail pressure it just twitching @ 28-30PSI) and all the while the car is bucking and acting up. Fuel pump duty cycle is also jumping from 30% to 40% and everywhere inbetween.
Give her about half throttle and the fuel pressure levels out @ 40PSI and duty cycle around 42%. GENERALLY it does it at light engine loads...but usually takes a rather high load to make it level out. At any point you go WOT it immediatly levels out and the car pulls all the way out maintaining a low 11.X A/F.
So whats going on here? It feels like a tuning issue, and am wondering if any of you guys have had simular problems? I also put in a STAGE 2 modified FPDM at the same time. So I unplugged it and connected the stocker...fired it up and immediatly started fluctuating. So its not that. Also doesnt seem to be bad gas as I already ran out over a 1/4 tank of fuel...and I wouldnt think water would cause my fuel pressure and pump duty cycle to jump around THAT much and then not effect it @ WOT.
Im also going to be putting in an 03/04 cobra hat assembly, because I NEED to run dual pumps. im still seeing 100% duty cycle at the topend. Anyone know where I can buy the hat WITHOUT the pumps? Or aftermarket thats a reasonable price (<$100) I may run custom baffling or just buy the cobra tank. Not sure yet.
thanks for any help guys. And if its tune related please tell me how to fix it with my pro race software.
(just waiting on SCT to activate it then I can use it)
If I cant get it figured out, I suppose ill try putting the PPRV back inline and see what happens.
I know this isnt an easy question to answer but just want some feedback before I go tearing into the tank again.
So I fire up the car and she fires right up. Go to town and get gas. Running like normal. I pull out of the gas station and the car starts missing! Look at my fuel pressure and its jumping from 25PSI to 50PSI at the pump (rail pressure it just twitching @ 28-30PSI) and all the while the car is bucking and acting up. Fuel pump duty cycle is also jumping from 30% to 40% and everywhere inbetween.
Give her about half throttle and the fuel pressure levels out @ 40PSI and duty cycle around 42%. GENERALLY it does it at light engine loads...but usually takes a rather high load to make it level out. At any point you go WOT it immediatly levels out and the car pulls all the way out maintaining a low 11.X A/F.
So whats going on here? It feels like a tuning issue, and am wondering if any of you guys have had simular problems? I also put in a STAGE 2 modified FPDM at the same time. So I unplugged it and connected the stocker...fired it up and immediatly started fluctuating. So its not that. Also doesnt seem to be bad gas as I already ran out over a 1/4 tank of fuel...and I wouldnt think water would cause my fuel pressure and pump duty cycle to jump around THAT much and then not effect it @ WOT.
Im also going to be putting in an 03/04 cobra hat assembly, because I NEED to run dual pumps. im still seeing 100% duty cycle at the topend. Anyone know where I can buy the hat WITHOUT the pumps? Or aftermarket thats a reasonable price (<$100) I may run custom baffling or just buy the cobra tank. Not sure yet.
thanks for any help guys. And if its tune related please tell me how to fix it with my pro race software.
(just waiting on SCT to activate it then I can use it) If I cant get it figured out, I suppose ill try putting the PPRV back inline and see what happens.
I know this isnt an easy question to answer but just want some feedback before I go tearing into the tank again.
