93 K2500 Suburban 454 Holley Sniper Upgrade

[OBS_George]

I used a caspers Y harness for the TPS sensor, hooked up tach signal from sniper to factory tach lead output spade connector, and kept all factory temp sensors hooked up, plus one new one for the Holley on intake manifold. It's been a while, I think that was the three sensor types it needed to figure out how to shift on the factory computer. If I had to do it all over again, just buy the $3200 Holley Terminator setup and have ability to customize the trans since it comes with built in GM trans controller, though it might need a harness adapter that Holley sells for the newer 93 up 4L80E plug which mine has since it was done when it was rebuilt.

Do you know if this is the correct Y harness? https://www.summitracing.com/parts/cei-108103

 

[LC2NLS6]

Do you know if this is the correct Y harness? https://www.summitracing.com/parts/cei-108103

That looks like it.

 

[OBS_George]

Can you post a picture of how you have it set up? I got one from summit and am confused on how this is supposed to work.

 

[LC2NLS6]

The blue wire goes to the factory blue wire of the truck's original harness. Unplug the holley tps sensor, plug the lead from the holley into the caspers adapter , then plug the other side of the caspers adapter into the hollet tps. Now the blue wire will get spliced into the factory GM tps lead. I didn't connect the other two wires, just the blue one, IIRC. Truck is at the shop getting new A/C lines replaced so I can't go grab a pic and I'm going from memory, which was last year so I think I have it right. My splice is insulated up so I'd have to undo it to confirm when I get the truck back.

 

[LC2NLS6]

Update - if I had to do it all over again, I'd want a trans controller to raise the shift point from 4250 to 5250. So, now I'm looking to add one of the MSD/Holley trans controllers as the next upgrade, or yank the sniper and install a terminator kit, maybe next spring. For fun I drop it into 1st gear and let it eat. It pulls to 5k no problem and actually barks the rears on the 1-2 shift.

Had to put all new brakes on, they were wasted, a/c blowing cold. Still tuning on it as it keeps running too rich a lot and I had the learning turned down so it never could get back to target afr. Manually tweaking each base fueling cell on the laptop software is the best way, trying to use the smooth feature just trashes the cells I've hand corrected.

 

[Supercharged111]

Update - if I had to do it all over again, I'd want a trans controller to raise the shift point from 4250 to 5250. So, now I'm looking to add one of the MSD/Holley trans controllers as the next upgrade, or yank the sniper and install a terminator kit, maybe next spring. For fun I drop it into 1st gear and let it eat. It pulls to 5k no problem and actually barks the rears on the 1-2 shift.

Had to put all new brakes on, they were wasted, a/c blowing cold. Still tuning on it as it keeps running too rich a lot and I had the learning turned down so it never could get back to target afr. Manually tweaking each base fueling cell on the laptop software is the best way, trying to use the smooth feature just trashes the cells I've hand corrected.

Why not just rechip the existing PCM? I imagine that would be cheaper.

 

[LC2NLS6]

I hate mail order tuning. I gave up on 'chip' upgrades and piggyback systems 15 years ago. I'm thinking holley efi will go on the 2009 burb and a couple turbos...and I could put the sniper on my uncle's 66 lemans... But yeh I could just slap a new chip in the stock ecm for the transcontroller on the cheap.

 

[Supercharged111]

I hate mail order tuning. I gave up on 'chip' upgrades and piggyback systems 15 years ago. I'm thinking holley efi will go on the 2009 burb and a couple turbos...and I could put the sniper on my uncle's 66 lemans... But yeh I could just slap a new chip in the stock ecm for the transcontroller on the cheap.

I meant for you to flash your own.

 

[letitsnow]

Is there anything left over 4000 rpms on a 454?

 

[Supercharged111]

Is there anything left over 4000 rpms on a 454?

Mine zings to 4700 so willingly here I'm debating bumping the shift points.