Fitech Ultimate 750 kit alternator issues/charging
This tread is for the ultimate 7000* users. A little background first, Twin turbo 403 cid all forge bottom end runs fine till getting into operating temps and the first fan kicks on @ 200. Alternator is a for a 2005-2013 truck 105 amp it has a 4 pin plug but fitech only needs the two. Voltage at start before warm up as follows 14.1,2 put volt meter on the battery same as things start warming we know voltage will drop due to heat and load. By the time i am at 199 before the fan kicks on battery 13.9 fitech displays 13.6 -13.5 It will start idling funny smooth 800 rpm then acts as if the injectors stop or coils stop advanced timing jump around then it smooths out for a bit till it want to have another fit. I have seen as low as 13.1-2 on the display with both fans running. Keep in mind this not a reman alternator and has been tested several times all ready only two 16" fans on the system and a small 10" manually operated by switch when the trans temp up.Everyone is telling me your alternator is to small OK this does not make since to me that this system is using all 105 amps to run. Cold start 14.1-2 Warm up 13.9 Battery 13.6-5 Fitech display. Makes me want to go out and buy an amp meter and test the alternator load.
Now here is my thoughts of trying fixing this issue, first I call Fitech to ask why the system maybe reading that low, first words was sounds like ground issue (no) large ground battery,frame,motor to fitech ground one head to second head all tied together parallel. Then verified the red,black red turns on/term L alternator black is 12v fused/ I,F term alternator. The alternator shop tells me the black doesn't do any thing till the start wire fails based on the alternator i have it will send info to a stock ECU and keep things runningat a reduced rate. Fitech didn't know the function of the black wire. I ask the Fitech guy what is the minimum voltage the Fitech will work because of the low readings, have to wait on that one. I explained to him here is what I am going to do. I will put the volt meter on the battery and measure the difference between the hand held, done that handheld reads 3-4 volts less then the battery don't know why will ask them. Second went to the local alternator shop and pickup a 4 wire plug with the sense wire, hooked up red and black - motor is cooled off - start voltages 14.0-1 battery 13.9 handheld - motor gets temp 200 turns #1 fan on - battery 13.7-8 handheld 13.3-4 - from the 4 pin sense wire is blue I take a jumper to 12v to simulate a load that tells the alternator to increase the output, battery is reading 13.9 to 14.0 handheld is reading 13.6-7. You may think he found a fix but no why is the handheld not matching # for #. Alternator wingdings are the pretty copper color no heat signs and how can I using all 105 amps.
Just a note i have all the latest and greatest procal software and handheld updates and some numbers don't match on them either such as fuel injector size and fan starting points be aware if you use procal use that not the handheld vise a versa use handheld not software, have not gotten an answer for that one either still searching and asking.
Great post. Going to move this to the LS section.
Thanks Austin also wanted to mention something else that might benefit the Fitech Ultimate guys that would take some of the load off of the fitech system is the MSD LS Coil Harness PN 88867. It provides a better constant source of direct power to the coils and load off the system. I am using this harness now on mine.
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Quote from rrobins on May 6, 2019, 8:11 pmThis tread is for the ultimate 7000* users. A little background first, Twin turbo 403 cid all forge bottom end runs fine till getting into operating temps and the first fan kicks on @ 200. Alternator is a for a 2005-2013 truck 105 amp it has a 4 pin plug but fitech only needs the two. Voltage at start before warm up as follows 14.1,2 put volt meter on the battery same as things start warming we know voltage will drop due to heat and load. By the time i am at 199 before the fan kicks on battery 13.9 fitech displays 13.6 -13.5 It will start idling funny smooth 800 rpm then acts as if the injectors stop or coils stop advanced timing jump around then it smooths out for a bit till it want to have another fit. I have seen as low as 13.1-2 on the display with both fans running. Keep in mind this not a reman alternator and has been tested several times all ready only two 16" fans on the system and a small 10" manually operated by switch when the trans temp up.Everyone is telling me your alternator is to small OK this does not make since to me that this system is using all 105 amps to run. Cold start 14.1-2 Warm up 13.9 Battery 13.6-5 Fitech display. Makes me want to go out and buy an amp meter and test the alternator load.
Now here is my thoughts of trying fixing this issue, first I call Fitech to ask why the system maybe reading that low, first words was sounds like ground issue (no) large ground battery,frame,motor to fitech ground one head to second head all tied together parallel. Then verified the red,black red turns on/term L alternator black is 12v fused/ I,F term alternator. The alternator shop tells me the black doesn't do any thing till the start wire fails based on the alternator i have it will send info to a stock ECU and keep things runningat a reduced rate. Fitech didn't know the function of the black wire. I ask the Fitech guy what is the minimum voltage the Fitech will work because of the low readings, have to wait on that one. I explained to him here is what I am going to do. I will put the volt meter on the battery and measure the difference between the hand held, done that handheld reads 3-4 volts less then the battery don't know why will ask them. Second went to the local alternator shop and pickup a 4 wire plug with the sense wire, hooked up red and black - motor is cooled off - start voltages 14.0-1 battery 13.9 handheld - motor gets temp 200 turns #1 fan on - battery 13.7-8 handheld 13.3-4 - from the 4 pin sense wire is blue I take a jumper to 12v to simulate a load that tells the alternator to increase the output, battery is reading 13.9 to 14.0 handheld is reading 13.6-7. You may think he found a fix but no why is the handheld not matching # for #. Alternator wingdings are the pretty copper color no heat signs and how can I using all 105 amps.
Just a note i have all the latest and greatest procal software and handheld updates and some numbers don't match on them either such as fuel injector size and fan starting points be aware if you use procal use that not the handheld vise a versa use handheld not software, have not gotten an answer for that one either still searching and asking.
I have an update to this for those who have similar issue like this. Today I went for a drive 79 degrees out humidity is high letting the truck get up to temp for the fans to kick with the sense wire hookup to the first fan power output from the relay because it needs 12V. Fitech handheld was reading 13.3-4 voltage. Then the first fan kicked on and the handheld went to 14.1-2 reading and the system ran flawless no in traffic hiccups I even kick on the tranny fan to see if there would be more draw on the system voltage was still good and drove without problem. here is the Ultima Select 105 Amp Alternator i run N111973A and the harness is a GM Repair Harness/Alternator pigtail 110-12046
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Hey !
what is the sense wire you are referring too ?