i have some questions about my swap

[1970 C10 MJW]

I have a few questions...
1) if i am not mistaken the ecm (99 silverado 4.8l 4l60e) the ecm provides the ground for the fuel pump ground, I have not gotten a tune, but the ecm will not turn the fuel pump on, i manually provided a ground to the pin my ecm is using and it came on. so my wiring is good.
2) according to lt1 swap.com the pinout says the ecm can run up to two fans, those two pins on the ecm also are providing a ground if i am correct. How do I tune this function in? (i am not a tuner i just want to know so i can discuss it with my tuner hes never tuned a gm car, but he is an experienced tuner we will use hp tuners)
3) on lt1swap.com it says we can use a pin for a tow haul mode
A)is this something that can be used with a toggle switch to run a totally differnt tune (for example a 91 octane tune and a E85 tune for the other) or is it only capable of slight adjustments to shift points etc like the factory does
B) what would be required to tune this in
4) what do i need to do with the TCC pin on the ecm? i have put the newer brake swith that has 4 pins (i believe) the two pins for the brake lights and two other pins
5) the tach output pin, I have an older sun 8k tach, what do i need to do with the one pin that i have on the ecm?
I may have more questions... but im not by the truck so i dont remember anything else atm. thanks for any input

[BR3W CITY]

Originally Posted by 1970 C10 MJW

I have a few questions...
2) How do I tune this function in? (i am not a tuner i just want to know so i can discuss it with my tuner hes never tuned a gm car, but he is an experienced tuner we will use hp tuners)

there is a Fan1 and Fan2, he shouldn't have an problem locating them. I will say tho, I would be very cautious about having someone tune your car who hasn't dealt with the way GM handles tq management and similar. I had a very good local tuner do mine, and after sitting down with a an o.e.m tuning engineer, we found issues all over. You can make a car run decent on a crap tune and never be the wiser until it blows up.

3) on lt1swap.com it says we can use a pin for a tow haul mode

Hart Rod and some others had a thread on this a little while back. If you dig back through the Lsx section they have a few pages on setting it up. The GenIII and GenIV handle it a little differently.

5) the tach output pin, I have an older sun 8k tach, what do i need to do with the one pin that i have on the ecm?
I may have more questions... but im not by the truck so i dont remember anything else atm. thanks for any input

There is a thread called Conventional Tach on LS2 that gives the part # for a pullup resistor allowing the use of regular tach's

[1970 C10 MJW]

what was the issues you had with your tune? just curious

[BR3W CITY]

Originally Posted by 1970 C10 MJW

what was the issues you had with your tune? just curious

While the tune functioned, there were certain areas and ways things were done that were incorrect (or less than ideal). For example, my injectors are 39lb/hr, but at LS rail pressure (58psi), that becomes closer to 45lbs. The tuner neglected to scale correctly, and instead pulled fuel other places when the tune was richer than expected. Little things like that can become very detrimental. On a stockish swap, they are less noticeable. The farther you push it, the more likely that "good enough" isn't.

[ls1nova71]

The PCM provides 12v to the fuel pump relay. You need to rewire your relay.

[1970 C10 MJW]

oh, i was not aware that it provide 12V ground.. what does it do as far as fan output? positive or ground?

[whitels1]

http://ls1tech.com/forums/conversion...swap-faqs.html