EFI upgrade?

[GoToGuy]

Without a proper functioning O2 sensor the ecm won't be able to adjust the air fuel ratio properly. When you rebuilt the TBI, you should changed the 02 sensor . A sniper would just be a bunch of cash for not much return . You have a base engine , where is the rest of the performance after the sniper?

 

[Erik the Awful]

There's a lot of hidden cost to a Sniper conversion. The only reason I went Sniper is because I put a significantly bigger cam in my 350. For a V6 I would just get the factory TBI running right. A Sniper's not going to make you more power on a stock engine. If you can't get the factory TBI running right, you're not going to be able to get a Sniper right.

 

[Gordy_]

If I have the time I'll replace the O2 sensor and see if it clears up. I wasn't really looking for performance with the sniper, but I do see how it could be a waste of time and money.

 

[Xombi]

Diagnosing the reason your truck is running rich will add to your skill set, and keep the silver in your pocket where it belongs.
Better mpg, more coin for thee.
Really rich runners wash down the sides of the cylinder wall leading to scoring, oil dilution, bearing wear.
You can clog a cat if a problem is ignored too long, and it is to no one's benefit.
Does the oil smell of gasoline?

 

[CumminsFever]

Keeping the 4.3 is a unique thing, and I wouldn't be afraid to run one. I always wanted to copy the 4.3 turbo design from the cyclone. It aint gonna win no speed wars, but it would motor around comfortably.
Give it some boost pressure and enjoy the 4.3!

 

[Scooterwrench]

If I have the time I'll replace the O2 sensor and see if it clears up.

May want to check your ECT sensor also. It plays a major role in air/fuel mixture. An OBD1 scan tool or downloading TunerPro RT and buying a data cord is almost a necessity when diagnosing these electro monsters.

 

[L31MaxExpress]

Sure you could do that, but for a 4.3, that would be crazy in my opinion!
If it's running rich, figure out why.
Is the 02 sensor working properly?
What makes you think it's running rich?
Is the exhaust burning your eyes?

The reason I say that's crazy is more of a financial one than anything else. The cost of a Sniper and intake would definitely be more than swapping in a 5.3LS and you would have a modernish V8 and $$$ left over.

I would not waste my time on a 200K mile 5.3L into any kind of a truck. Considering a stock L31 350 with a small cam (GM 7395 196/206 marine cam for comparsion sakes) makes ~50 ft/lbs more torque than even the L83 Direct injected 5.3L does at 2,500 rpm. The L83 5.3L makes signifigantly more power than the older Gen III and Gen IV 5.3L does everywhere. The 350 kills the older 5.3Ls even worse where you spend 95% of your time actually driving. An old L31 350 even has more guts than a LY6 6.0L that has VVT under ~3,200 rpm.