98 GMC Sierra 5.3 Swap

[klug99]

Hey guys I've got a couple questions. Im doing a swap on my 98 GMC. I have a Street and Performance harness. Im using the factory guages so I installed the factor (98) temp and oil sending units. Does the LS computer need a temp sender also? My harness has the transmission plugs also. Do I use the 98 ones or the LS ones or mix them? I was thinking use the stock Neutral safety wires but what about the speed sensor and stuff? Thanks Chris

[shmiet]

Doing the same swap right now haha. Yes the ls pcm needs the coolant temp signal. Remove the obs transmission wiring, use the ls transmission wiring. The speed sensor signal will need to be split between the two pcms. Unfortunately I don't know about the NSS. Hope that helps a bit.

[klug99]

Doing the same swap right now haha. Yes the ls pcm needs the coolant temp signal. Remove the obs transmission wiring, use the ls transmission wiring. The speed sensor signal will need to be split between the two pcms. Unfortunately I don't know about the NSS. Hope that helps a bit.

Yes it does. I just saw that this morning too. haha. Are you still using the stock 4L60E?

[shmiet]

Ya I'm using the obs 4l60e, with LS housing, Shift kit, wider band for 2nd and 4th, billet solenoid, and a few other upgrades to handle the hp.

[Lextech]

Why would you want to use two PCMs on a 98 truck????????

Jeff

[klug99]

[QUOTE=Lextech;511309]Why would you want to use two PCMs on a 98 truck????????

Jeff[/QUO

Because it runs the abs

[Lextech]

I have had a 12200411 LS PCM in my 98 for about 7 years now. My ABS works perfectly.

Jeff

[klug99]

This is my first swap. Im new to the whole LS stuff. I was told to leave the factory one there. Do I not need it? What runs the abs if you remove it?

[shmiet]

Lextech,

So for vss to the factory gauge you just used the LS pcm output signal and soldered it to the c100? if so did you do that pretty much for all the sensors? Will all the gauges work with proper tuning of the LS pcm? Will the 4896 pcm work?, from what ive read the 4896 just has less RAM.

[Lextech]

Klug, On your 98 harness C1-15 Yellow/Black wire of the PCM will be installed into C2-49 of the Gen3 PCM. BUT---This is when using a factory harness. Since you have an aftermarket harness and I don't know what it does or doesn't have in it---You may want to run the two PCMs. If you ever do another one of these trucks, don't use two PCMs. It is not necessary.

Shmiet, I didn't mess with the C100 connector. I repined the stock harness for the Gen3 PCM and added 10 wires to the harness to run a Gen3 engine. All of my gauges work fine. The 4896 PCM will work.

Jeff