Hi,

GM offers vortec 4300/LU3 V6 MPFI on its S10/blazer since 2002, and i c LG3 variant, which is used on chevy blazers built in Brazil and china markets, anybody could help tell the difference between LG3 and LU3? I guess the difference is minor...!

Thanx

 

While we have a 2002 I do have personal experience on 1998 engine differences between a 1998 4.3 W and X eighth digit VIN numbers.

There seems to be none. The owner's manual states the W as 5 more HP than the X but after doing engine swaps from 1998 X to 1998 W engines we found the X out of the 1998 2WD S10 to be idential to the 1998 W out of a 4WD auto Blazer. No oil pan, oil filter, exhaust manifolds, computers, etc differences.

With the S10 computer the W engine started up and is running fine. So in that generation they seem to be plug and play.

Now engines not controlled by the EPA may be vastly different.

 

From Wikipedia, take it for what it's worth:

LU3 and LG3 MPFI

2002 saw major changes to the 4.3L fuel injection system. For 2002 California emission Chevrolet Astros, GMC Safaris, Chevrolet Silverados and GMC Sierras all came equipped with the updated LU3 4.3L. 2003 saw the L35 discontinued and the LU3 replacing it in all other applications. A new variation was also introduced in 2003, the LG3. For 2004 to 2009 the LU3 has been the only 4.3L produced.
The biggest change to the LU3 and LG3 was the fuel injection system. These engines used a multipoint fuel injection system, with six Multec II fuel injectors mounted at each intake port on the manifold. The composite upper intake manifold and cast aluminum lower intake from the L35 engine is also used on the LU3. The LG3 uses a cast aluminum upper intake and a cast iron lower intake.
The LU3 also received a quiet cam to help reduce vibration at both idle and high engine speeds. This camshaft used the same lift and duration as the older design, but the cam was reprofiled to keep the valve lifters in full contact with the cam lobes as the cam ramps down.
The LG3 was used in Chevrolet and GMC S-series pickups and was only produced for 2003. The LU3 was used in the Chevrolet and GMC full-size trucks and vans, the Chevrolet Astro and GMC Safari vans and the Chevrolet S-10 Blazer and GMC S-15 Jimmy. The LG3 was rated at 180 hp (130 kW) and 245 ft·lbf (332 N·m) of torque. The LU3 was rated at 190-200 hp and 250–260 ft·lbf of torque.

 

CHEVROLET ASTRO SAFARI FUEL INJECTOR 4.3L VORTEC SPIDER FJ10565 12568332A | eBay

So with this update in a 1996+ one gains some of the edge of the new engine version?

Just put it in the new engine for the 1998 S10 that works well it seems but had never ran the engine before. Does the injector at each intake valve help with MPG?

 

Say, what!!! Unbelievable. What's old is relatively new, again!