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Just about finished installing my Fitech. Only issue is, I have a truck alternator and the plug doesn't fit. How can I connect it without cutting the FiTech harness?
Just about finished installing my Fitech. Only issue is, I have a truck alternator and the plug doesn't fit. How can I connect it without cutting the FiTech harness?
If the plug doesn't fit, the Fitech ECM may not be compatible with it.
That's odd. .both my 70050 units plugged right into both my truck alt'z....fitech boys might have built your harness Friday afternoon and put a ford alt. Plug on it.... I seen them do it to one of mine with a ford map plug sensor. ....
As I understand it, GM vehicles with four pin plug alternators only used two-or sometimes just one wire in the plug. I would assume GM has got up to speed and now uses smaller plugs for the number of contacts needed-and nothing extra.
The Fitech Ultimate LS system is designed to emulate a GM LS system-including the alternator. There are adapter cables to use a 2 pin alternator in a four pin vehicle-but I can't state if they work properly. I'd say it's best to get an alternator that matches the harness plug.
The newer 2 pin alternators are PWM controlled by the ECU. The ECU changes the duty cycle and thus demands different voltage output from the alternator. The 4 pin alternators need the L terminal energized. This can be done through the vehicle wiring with an inline resister or through the "ALT" idiot light in the dash. The S terminal is optional, but I have found it beneficial to connect it. It should be wired to a place in the electrical system where most of the power is distributed. This is not the same thing as the battery.
Just finished my install and the only problem I have is the car won't shut off. It seems like feedback from the Alt.
With the key off no power to either wire
With the key on power to both wires.
Once you shut the car off (it continues to run) there is still power to the red wire.
I tried adding a 470 resistor and that didn't fix the problem
Where did you hook your power wires up? Your theory doesn't sound right to me. I cant think of anything that would receive power from the alternator that does not receive battery power as well. Did you own/drive this car prior to the swap? Maybe you have a relay or ignition switch issue.
Just finished my install and the only problem I have is the car won't shut off. It seems like feedback from the Alt.
With the key off no power to either wire
With the key on power to both wires.
Once you shut the car off (it continues to run) there is still power to the red wire.
I tried adding a 470 resistor and that didn't fix the problem
Any advice? Thanks
Please identify what you call both wires. What are each for? Are they in the Fitech harness?
Where did you add a 470 Ohm resistor and why? This is a new one to me.
Currently Im having a bish of a time getting my assembly to run correctly. Its a Gen 3 DBC computer tuned with HP Tuners with the help of Vengeance Racing. Im getting some idle surge and idle hang that I cant seem to get tuned out. And Im getting no help from Vengeance on it.
Aside from that, the overall size of the Gen 3 computer is ridiculous. So Ive been thinking about picking up the FiTech unit with the touch screen.
Looking to see if anyone has used it and if it works as good as they say it does and if its worth swapping over from the Gen 3 controller.
Looking to see if anyone has used it and if it works as good as they say it does and if its worth swapping over from the Gen 3 controller.
Most who use this system have fairly good luck. A few have pretty bad problems, usually caused by poor or incorrect installation. There have been some bad ECMs and harnesses but Fitech support, which has been notoriously bad, has been improving.
The ECMs are all the same and to have 4L60e/4L80e control, only an added harness is needed. There are basic systems and full blown systems with intake, TB, rails & injectors.
At this time, there are no inputs to tell the system to go to a different tune for Nitrious.
The PWM fuel pump output Fitech details in this kit does not exist.
Unrelated to the company Fitech is a good forum for more info. Just register and I have a lot posted there. https://fitechefituning.com/
Most who use this system have fairly good luck. A few have pretty bad problems, usually caused by poor or incorrect installation. There have been some bad ECMs and harnesses but Fitech support, which has been notoriously bad, has been improving.
The ECMs are all the same and to have 4L60e/4L80e control, only an added harness is needed. There are basic systems and full blown systems with intake, TB, rails & injectors.
At this time, there are no inputs to tell the system to go to a different tune for Nitrious.
The PWM fuel pump output Fitech details in this kit does not exist.
Unrelated to the company Fitech is a good forum for more info. Just register and I have a lot posted there. https://fitechefituning.com/
Thanks Paul! I'll check out that forum. Im mainly just tired of looking at the huge gen 3 ECM and would like the convenience of touch screen tuning.
Please identify what you call both wires. What are each for? Are they in the Fitech harness?
Where did you add a 470 Ohm resistor and why? This is a new one to me.
On my '51 Chevy truck, which has an LS1/4L60 out of an '04 GTO (stock harness and PCM) I had to relocate the alternator which required a different style alternator than the sock GTO. With that setup a 470 ohm resistor was required so the alternator wouldn't back feed and keep the truck running. It works great but I never tried it without the resistor to know if it was even an issue.
On the Fitech alternator plug there are 2 wires (brown and red I think) I believe the red wire is the exciter wire. So I added a resistor to it and still have the same issue. I double checked all of my wiring over the weekend and it all looks correct. Called Fitech this morning and they were no help.
On my '51 Chevy truck, which has an LS1/4L60 out of an '04 GTO (stock harness and PCM) I had to relocate the alternator which required a different style alternator than the sock GTO. With that setup a 470 ohm resistor was required so the alternator wouldn't back feed and keep the truck running. It works great but I never tried it without the resistor to know if it was even an issue.
Well if it's working for you great, I'd not change it.
When I planned my system, I chose a Power Master AD244 200 amp alternator with the oval plug and it works without issue controlled by the Fitech ECM.
01-29-2019, 09:31 AM
