#'s seem way too low?

[shanezt]

i was told MOST 03-04 cobra's lose voltage under WOT. what the ecu thinks it has for voltage does not matter. i have said this before i can datalog and my voltage in the log will be 12volts or less BUT, i can use a real volt meter and i have over 13volts at the battery. the ecu itself does not need 13volts to operate. ever notice that your volts drop off at high rpm but your blower motor speed stays the same? you should only worry about the current at the pumps and check that independantly.

the only way to tell for sure in your case, i would read the actual voltage at the pumps and see if it does indeed drop off there. read it with a volt meter not through ODB2.

 

[THE_EVIL_TW1N]

Don't be confused by how many post he has. He's one of the best tuners in the southeast! Just a little fyi.

You're right. :bash: I did a bunch of searches and found that the alt indeed does not turn off at WOT. I saw it had been suggested in a bunch of threads as a possible reason for the voltage drop, similar to the Marauder.

I also saw that when people bought whole new alternator set-ups, from OEM replacements to stout alternator set-ups with full wire upgrades and such, that the voltage drop was still present and showed no improvement.

sounds like shanezt has a good idea. :read:

 

[The Notch]

i was told MOST 03-04 cobra's lose voltage under WOT. what the ecu thinks it has for voltage does not matter. i have said this before i can datalog and my voltage in the log will be 12volts or less BUT, i can use a real volt meter and i have over 13volts at the battery. the ecu itself does not need 13volts to operate. ever notice that your volts drop off at high rpm but your blower motor speed stays the same? you should only worry about the current at the pumps and check that independantly.

the only way to tell for sure in your case, i would read the actual voltage at the pumps and see if it does indeed drop off there. read it with a volt meter not through ODB2.

Your right about the pump voltage, but the ecu is also very dependant on voltage especially the effect on injector pulswidth at such a low voltage, Ive logged Hundreds of cobras and they all drop to around 12.5-13.0v at wot, but never to 11.0 unless theirs an alternator issue.

 

[THE_EVIL_TW1N]

Your right about the pump voltage, but the ecu is also very dependant on voltage especially the effect on injector pulswidth at such a low voltage, Ive logged Hundreds of cobras and they all drop to around 12.5-13.0v at wot, but never to 11.0 unless theirs an alternator issue.

from what i've read (from my enlightening), super low voltage can also mess with the MAF readings as well. So it may not be just that the fuel is getting a bad reading.

It could be that the MAF is reading lower than it should, resulting in less fuel being pumped in than is necessary = lean.

 

[The Notch]

from what i've read (from my enlightening), super low voltage can also mess with the MAF readings as well. So it may not be just that the fuel is getting a bad reading.

It could be that the MAF is reading lower than it should, resulting in less fuel being pumped in than is necessary = lean.

Yeah absolutly, usually when voltage drops that much the maf will read inacuratley, most of the time the maf counts will become very erratic at low voltage and high load.

 

[shanezt]

hmmmm, in my own fiindings (not as well verse with fords as you guys) even dropping to 11 volts for a short time should not effect the pcm and its voltage control (maintaining a 5volt supply to sensors, pulsing inj and pumps, etc.) i find it hard to believe that his voltage is indeed dropping to 11volts! i know the datalog says so but i would want to see real voltage readings not from obd2.

 

[THE_EVIL_TW1N]

hmmmm, in my own fiindings (not as well verse with fords as you guys) even dropping to 11 volts for a short time should not effect the pcm and its voltage control (maintaining a 5volt supply to sensors, pulsing inj and pumps, etc.) i find it hard to believe that his voltage is indeed dropping to 11volts! i know the datalog says so but i would want to see real voltage readings not from obd2.

I guess the only way to really find out would be from datalogs with more info from the OP.