cobra dual pumps voltage questions

[1crzhrs]

i have the dual cobra hat and pumps in my 04 gt with the hellion 61mm single turbo kit on there with 42lb injectors.

what duty cycle are the pumps normally running at idle, and at what voltage is being commanded via the tuning software?
i have the x-cal 2 and it's comanding in the 5.xxx range at idle and running 41-43% duty cycle at idle.

it is maxing out around 4800-4900 rpm's at 100% duty cycle, but only commanding 7.5 volts and i have 11.8 available to the pumps. should the voltage command be turned up in the tune, or am i just missing something here with my lack of knowledge on the subject.

so far i have only 7 degrees of timing in it, and on the 11.2-11.3 a/f range at this point.

any help or advise would be a huge help here. tested and swapped out 4 different pumps and everything in the hat, tank, pumps, and the wiring is all good.

 

[Ontariomystic]

Sounds like you need a 03-04 Cobra Fuel Pump Voltage table in your tune. Maybe a tuner can chime in and confirm that

 

[1crzhrs]

i'm supposedly running the cobra table. but it's only commanding 7.5 volts at wot. didn't know if that could be adjusted up, or if my pump set up is not on par.

 

[Black306]

I don't recall off hand what the voltages are, but the duty cycle at idle should be ~16%. If you are at ~42% at idle, something is definitely wrong.

 

[1crzhrs]

we jumped up the table to 11.5 and it made no difference. the pumps will only push the rail pressure needed and that's it.

any ideas on what to check? think i need a wring upgrade, or would that make any difference? boost a pump?

 

[Cobra-21]

I don't recall off hand what the voltages are, but the duty cycle at idle should be ~16%. If you are at ~42% at idle, something is definitely wrong.

My stock MAF reads around 40% at idle according to my Predator (FPDC value x 2).

 

[1crzhrs]

hank everyone for their help and ideas. it is much appreciated!
well, i will do the wiring upgrade just so it's done as a safety precaution.

as far as what solved the problem,

IT WAS THE BATTERY!!!!!!!

i had the optima in there and it has been going dead the last couple weeks even after charging it fully. so i stopped at ford today and got a 04 cobra battery and put it in. made 6 different data log runs pulling to 6000-6500 rpm's thru the gears and never went over 94% duty cycle. it's also rich as hell thru the entire band in all gears looking at the wideband. so i figure the wiring upgrade might drop me some, but i'm good now without it. once it gets into the 90's the voltage rises and stabalizes the duty cycle. feels good going thu the gears with no timing and extra fuel in it! lol can't wait till the tune gets under way! i'm sure it'll be on video and mabey a few runs thru the gears on the closed track we frequent!

 

[Maching-U]

Is your alternator charging the battery? What voltage is it putting out?

 

[1crzhrs]

Is your alternator charging the battery? What voltage is it putting out?

alt is good, 14.4

the optima is 5 years old.

 

[jm@ReischePerf]

That's odd though the alt should be capable of providing enough power for the pumps even if the battery is weak... you may have another issue so keep a close eye on your voltage.

 

[Digital]

That's odd though the alt should be capable of providing enough power for the pumps even if the battery is weak... you may have another issue so keep a close eye on your voltage.

This is very true. Keep a extremely close eye on your electrical especially if you have a stereo. You dont want to be at 7k rpm and all of a sudden hit that duty cycle at 4k like before.. pop..

 

[Hkaiser83]

A dead battery can definitely screw with the voltages in a car even if the alternator is working full power.