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Vortec CSFI to MPFI conversion
covert your early 4.3L 5.0L & 5.7L GM Vortec to a more reliable MPFI spider system


This article will explain the benefits of the GM CSFI to MFI Spider Conversion for All 1996-2001 4.3L 5.0L & 5.7L GM Vortec Engines

As you may know the early style Central Sequential Fuel Injection (CSFI) or Spider units tend to fail overtime. This is mainly due to the poppet valves becoming plugged with carbon deposits. Some symptoms of a bad poppet valve are hard starting due to a leaking poppet valve, misfire codes, rough idle, loss of power and performance and a noticeable decrease in fuel economy.  

notice in the picture below how far the Poppet valve seats in the intake. The tip of the poppet valve conducts a large amount of heat allowing for carbon to build up on the tip of the valve.

4.3L Vortec Spider Poppet Valve

 the next picture shows the new design installed in the same exact intake manifold. Notice how the nozzle of the injector is recessed away from the intake valve.  The plastic pintle tube acts as an insulator to the injector tip which decreases the amount of carbon that's able to develop on the end of the injector. 


GM has engineered a new Spider unit and it was used on 2002-2007 Vortec motors.  This same unit can be installed on your 1996-2001 Vortec with no mods needed. 

5.0L & 5.7L GM Vortec Spider MPFI

The MFI (Multiple Flexible Injection) Spider incorporates a small electronic fuel injector at the end of the fuel line.  Notice the long pintle cap tube attached to the injector.  This long tube allows the end of the injector to be recessed away from heat and vapors that cause carbon build up on the end of the injector 

The two photos below show the early style spider unit installed and the new MFI spider installed on the same 4.3L Vortec intake.

 This is an easy conversion and does not require any special tools or modifications for installation


 This is a must have upgrade for any GM Vortec motor that incorporates SCPI injection. By performing this upgrade you will notice a smoother idle, better throttle response and all-around better performance. 

please click on one of the links below to purchase your New Delphi MFI Spider unit today!

1996-2007 4.3L vin [W] complete spider unit 

1996-2007 5.0L & 5.7L complete spider unit