Question: I have a 1994 S-10 Blazer with a 4.3-liter EFI engine with the W VIN number. I have a huge problem starting the engine. It has a new fuel pump, filter, and the like. I would like to install the fuel nut kit, recommended by GM. Can you tell me the part number and the seller?

Answer: Be careful: The "nut" kit is simply the fuel pressure and return lines that feed the injector assembly located beneath the intake plenum. If either line were leaking, you would typically notice a raw fuel smell. If the leak were at the pressure line, it would also produce a hard start (extended crank) condition. Once confirming the basics--good spark, fuel pressure, and the engine being mechanically sound--the correct repair involves replacing the entire CMFI (central multiport fuel injection) assembly, plus the nut kit.

The biggest problem with this system is the "poppet nozzles." Instead of having an electronically controlled fuel injector at each cylinder, CMFI injects the fuel from an injector assembly, through lines to each poppet nozzle (positioned at each cylinder). These poppet nozzles are easily contaminated (where standard injectors aren't), and cause a fuel leakage into the cylinders. This can cause a hard or no-start condition, catalytic converter smell, rich condition, or misfire. The best way to go on parts is OEM. Go to a Chevy parts department or www.acdelco.com, and purchase the injector kit (part #217-1431) and the nut kit (part #17112705), plus all related plenum gaskets to do the job.


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If you have a technical question regarding your pickup, SUV, or van, feel free to contact Alex, a master technician with the National Institute for Automotive Service Excellence. Send a letter to him in care of Truck Trend Garage, 831 S. Douglas Street, El Segundo, CA 90245, or e-mail us at trucktrend@sourceinterlink.com. Please include the VIN with your question. Due to the volume of questions received every month, we cannot guarantee that everyone's question will be personally answered or will appear in the magazine.

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