I just completed the SFI to MFI conversion on my '96 Suburban with the 5.7 Vortec. I would recommend this conversion to anyone having problems with the original fuel injection system. My Suburban runs great now, smooth idle and better off-idle throttle response.
My Suburban was hard to start when hot, fuel was leaking into the intake manifold causing a flood condition. It would sometimes backfire and set the check engine light. I was guessing that it was either leaking injectors (or poppet valves) or a leaking fuel pressure regulator.
After removing the upper intake manifold, I could see that it was probably a leaking fuel pressure regulator because the carbon build up was washed away under the regulator.
Removing the upper intake is not difficult, but it takes a lot of time. I decided that once the upper intake was removed, I might as well convert to MFI which already includes a new regulator.
The part numbers for the conversion have been listed here before, but I will list them again:
93441235 - Fuel Injector Assembly
17113206 - Upper Intake Manifold Gasket Seal Kit
93442096 - Fuel Injector Bracket
All three parts are available from gmpartsdirect.com
You should also replace the two O-rings on the fuel line connections near the firewall:
22514722 and 22516256
gmpartsdirect has these, but they only sell them in packages of 10. You can buy them from your local Chevy dealer for around $1 each list price.
Comments about the conversion:
1. Take digital photos of all the hoses and wires before you pull everything apart, they will help when you re-assemble everything.
2. Keep track of the locations of the different intake manifold bolts and brackets, I stuck them through a piece of cardbord in their appropriate locations.
3. After all the bolts, hoses and wires are removed, the upper intake may still be difficult to remove. It is sealed to the SFI system with a large O-ring. Just keep pulling straight up and it will eventually come loose.
4. I don't know why you need a new bracket. I replaced mine, but the new bracket was identical to the old bracket.
5. Some people claim that you can save money by re-using the intake manifold gasket because it is formed rubber. Considering the amount of time required to remove and replace the manifold, I wouldn't recommend re-using gaskets.
