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How to Install Multiport Fuel Injection Conversion 96-99 GMC K1500

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How to Install Multiport Fuel Injection Conversion 96-99 GMC K1500

Created on: 2017-04-13

This video has all the steps needed to replace the multiport fuel injection if it is clogged or damaged

  1. step 1 :Removing the Air Intake
    • Loosen the throttle body thumbscrew by hand
    • Disconnect the breather hose from the throttle body
    • Disconnect the mass airflow sensor
    • Disconnect the intake air temperature sensor
    • Unclip the air box tabs
    • Lift off the air box cover
    • Pull the air intake up and out
    • Remove the bottom of the air box
  2. step 2 :Removing the Throttle Cables
    • Flip out the throttle lever out
    • Pop the plastic rod out of its clip on the throttle cable
    • Pull the cable around until it sits into the notch
    • Slide the cable end out
    • Collapse the tabs on the throttle cable retainers with a pair of pliers
    • Remove the 10mm bolt from the bracket
    • Lay the cables out of the way
  3. step 3 :Disconnecting the Wiring Harnesses
    • Disconnect the throttle position sensor
    • Disconnect the idle air control connector
    • Disconnect the vacuum solenoid connector
    • Disconnect the ignition control module
    • Disconnect the injector connector
    • Pry out the tabs and remove the injector connector
    • Disconnect the MAP sensor connector
    • Pop off any wire harness retainers
    • Disconnect any hoses attached to the intake
    • Release the clamp on the vacuum booster hose
    • Loosen the hose free
    • Remove the three 10mm nuts securing the EVAP solenoid
    • Remove the two 10mm nuts on the ignition coil control module
    • Lift up and remove the harness retainer bracket
    • Remove the three 10mm nuts below the bracket securing the ignition coil to the intake
    • Hang the bracket off to the side
  4. step 4 :Loosening the Fuel Fittings
    • Remove the cap on Schrader valve on the fuel rail
    • Place paper towels around it
    • Press the top pin with a flat blade screwdriver
    • Remove the two T20 Torx screws from the distributor
    • Move the cap out of the way
    • With a 16mm flare nut wrench, loosen the fuel fittings behind the intake on the driver side
    • Remove the two 10mm nuts securing the fuel line bracket from the top of the engine
  5. step 5 :Removing the Fuel Line
    • Remove the 10mm nut underneath the thermostat/upper radiator hose bracket
    • Remove the 10mm nut securing the bracket over the EGR tube
    • Remove the remaining 10mm nuts from the intake manifold
    • Remove the two 8mm nuts securing the fuel lines on the injector bracket
    • Remove the bracket
    • Remove the fuel lines from the housing
    • Remove the fuel lines
  6. step 6 :Removing the Multiport Fuel Injection
    • Work the upper intake up and off
    • Pinch the tabs and remove the eight injectors
    • Pry out the injector's bracket
    • Remove the injectors up and out
  7. step 7 :Installing the Multiport Fuel Injection
    • Insert the injector into the retainer
    • Face the front of the vehicle
    • First front arm to the left goes to cylinder 2
    • Second inside front arm to the left goes to cylinder 4
    • First front arm to the right goes to cylinder 1
    • Second inside front arm to the right goes to cylinder 3
    • First back arm to the left goes to cylinder 8
    • Second inside back arm to the left goes to cylinder 6
    • First back arm to the right goes to cylinder 7
    • Second inside back arm to the right goes to cylinder 5
  8. step 8 :Installing the Intake Manifold
    • Clean off the surface with cleaner
    • Remove the old gasket from the upper intake manifold
    • Install a new gasket
    • Insert the upper intake manifold into place and work it down for a full seal
    • Start at the 12 o'clock position and work your way around when replacing the 10mm bolts
    • Follow the torque sequence to 44 inch-pounds or 5 newton-metres
    • For the second pass, follow the torque sequence to 88 inch-pounds or 10 newton-metres
  9. step 9 :Installing the Fuel Line
    • Reinstall the cylinder head temperature sensor
    • Reinstall the bracket over the ignition coil and control module
    • Reinstall the fuel lines
    • Reinstall the fuel line bracket
    • Tighten the two 8mm nuts to the fuel line bracket
    • Reattach the fuel lines at the rear of the intake manifold with a 16mm flare wrench
    • Reinstall the fuel Schrader valve
  10. step 10 :Connecting the Wiring Harnesses
    • Reinstall the distributer cap
    • Tighten the two T20 Torx screws
    • Reconnect the electrical connectors
    • Tighten the three 10mm nuts below the bracket securing the ignition coil to the intake
    • Press in the harness retainer bracket
    • Tighten the two 10mm nuts on the ignition coil control module
    • Tighten the three 10mm nuts securing the EVAP solenoid
    • Tighten the clamp on the vacuum booster hose
    • Connect the hoses attached to the intake
    • Pop on any wire harness retainers
    • Connect the MAP sensor connector
    • Press the injector connector into place
    • Connect the injector connector
    • Connect the ignition control module
    • Connect the vacuum solenoid connector
    • Connect the idle air control connector
    • Connect the throttle position sensor
  11. step 11 :Reinstalling the Throttle Cables
    • Insert the throttle bracket to the throttle body
    • Tighten the 10mm bolt to the throttle body
    • Connect the throttle cables into the clips
    • Open the throttle body blade
    • Loop the throttle cable into the square slot
    • Send the round cruise control cable into its slot and snap it over its tab
  12. step 12 :Installing the Upper Air Intake
    • Install the lower half of the airbox
    • Press the upper intake into place
    • Tighten the thumb screw
    • Connect the PCV breather hose
    • Reinstall the MAF sensor
    • Reinstall the air intake sensor
    • Reinstall the air box lip

Tools needed for replacement

  • General Tools

    Pick

  • Materials, Fluids, and Supplies

    Paper Towels

  • Pliers, Cutters & misc Wrenches

    Channel-Lock Pliers

  • Ratchets & Related

    Ratchet

    Torque Wrench

    Socket Extensions

  • Screwdrivers & Related

    Flat Blade Screwdriver

  • Sockets - Metric

    8mm Socket

    10mm Socket

  • Star Drivers & Sockets

    T20 Driver

  • Wrenches - Metric

    16mm Wrench

Installation Video
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Hi, I'm Mike from 1AAuto. We've been selling auto parts for over 30 years! We're dedicated to delivering quality auto parts, expert customer service, and fast and free shipping, all backed by our 100% satisfaction guarantee. So visit us at 1AAuto.com, your trusted source for quality auto parts.

In this video, we're going to be working with our 1996 GMC Sierra K1500. We're going to be showing you how to remove and replace your old CFI or central fuel injection unit and replace it with a newer style MFI or multi-port fuel injection conversion kit.

If you like this video, please click subscribe. We have a ton more information on this and many other vehicles. If you need this part for your truck, you can follow the link down in the description over to 1AAuto.com

Here are the items you'll need for this repair: 8-10mm sockets, ratchet, socket extension, T20 Torx socket, 16mm wrench, flat blade screwdriver, pliers, hooked pick, paper towels, solvent, torque wrench

Lift up on the latches and remove the upper portion of your air box. Unplug the intake air step and mass air flow sensors. Pop the breather line off and undo the thumb screw. Rock the upper part of the intake forward and remove it from the vehicle.

Disconnect the throttle cables from the throttle body—the cruise cable just pops forward. With the throttle body open, you should have enough slack in the throttle cable to bring it around to the gap and slide the end of the cable out. Remove the throttle cable bracket. There's a 10 millimeter bolt at the throttle body, and a 10 millimeter nut down on the manifold side. We'll do this with a 10 millimeter socket and ratchet. Lift up and remove the throttle bracket and all we're going to do is just pull this out of the way and tuck it off to the side.

Label and remove all of the electrical connectors. It's not entirely necessary to label these, but I like to just because once you get back to putting everything together it can be a little tricky remembering what went where. We're going to disconnect everything attached to the upper intake manifold as well as the ignition coil module because those will have to come off.

We should have enough room to release the harnesses and move them out of the way while we lift this off. We'll disconnect the throttle position sensor, idle air control connector, the purge and vent solenoids on the side, the ignition control module, and the ignition coil, and of course the injector connector at the top. We'll pop that tab off. It may help to have a small flat blade screwdriver to pry out the tabs and remove the injector connector. You'll also need to undo the connector on the manifold absolute pressure sensor. Pop off any wire harness retainers you find around the vehicle as well. Just to help get some more slack on the harness for when we remove the intake, disconnect any hoses attached to the intake.

We have one on the passenger side, one on the driver's, and then one at the back for the vacuum booster, which we'll need a pair of pliers to remove. Use a pair of pliers to release the clamp on the vacuum booster hose. Sometimes if the hose is stuck, it helps to just hold the edges with a pair of pliers and work it side to side to loosen it up. Remove the three 10 millimeter nuts securing the evap solenoids to the sides of the intake manifold with a 10 millimeter socket and ratchet. We'll now remove these from the vehicle. You can either just hang them off to the side like this or you can undo that connector if you'd like.

Remove the two 10 millimeter nuts on the bracket for the ignition coil and control module. We'll then lift up and remove this harness retainer bracket. Move the harness retainer bracket out of the way. You'll then need to remove the three 10 millimeter nuts below that bracket securing your ignition coil to the intake. You can then hang that bracket off to the side as well. Remove the cap on the fuel straighter valve. It's usually best to use a fuel pressure test tool to thread on there, which usually has a relief hose on it that you can place into an appropriate container. You just want to push down here and make sure you bleed off any pressure in the fuel system.

Using a T-20 Torx driver, you can use a screwdriver and a bit and a ratchet like I am here. Remove the two screws securing the distributor cap onto the distributor. Now, we're only doing this to gain access to the fuel lines, so you should just be able to unscrew the cap and push it back and out of the way without undoing any of your plug wires. If you do find the need to undo your plug wires, just be sure to mark where they came off of so they all go back in the same place.

Now, you're not really going to be able to see the other T-20, because it's on the back side of the cap, but you can see the little indent there and just kind of do that one by feel. Where this screw is hard to reach and see, and you don't want to drop it, I suggest lifting up on the cap while you unscrew it to keep it in there. Once it's out, it should be a little easier to pop out and keep your hands on it. We're going to just move this out of the way. Using a 16 millimeter flare nut wrench, loosen the fuel fittings on the back of the fuel lines. These are down behind the intake on the driver's side. Then remove the 10 millimeter bolt securing the fuel line bracket to the back of the engine block. We'll do this with a 10 millimeter socket ratchet extension.

Remove the 10 millimeter nut underneath the thermostat hose or the upper radiator hose with the 10 millimeter socket and ratchet. This is securing a bracket that holds a little more of the wire harness in place, so we'll want that out of our way. It looks like this one is stuck together a little bit, so we're actually pulling the stud out too here it would appear. That's perfectly fine, because we're just going to hang this out of the way. We would need to remove that stud in order to take the manifold off anyway. We'll also want to remove the 10 millimeter nut securing the bracket over the EGR tube. We'll lift that bracket up and move that out of the way as well.

Now some of our nuts came out with the studs on them, so just follow around the perimeter of the upper intake manifold, which is the black plastic piece, and you should have somewhere between 13 or, in our case, eight studs left to remove. So just go around and just take all of those out with a 10 millimeter socket and ratchet. Remove the two eight millimeter nuts securing the fuel lines onto the injector bracket here. You'll want to lift the bracket off first just a little hold down that we just unscrewed there. Remove that and then pull the fuel lines out of the housing. You may need a little help prying these up. Remove those fuel lines completely.

Work the upper intake. This can take a little bit of effort to remove because the injector assembly here actually stays in the lower manifold so when we pop this cover off, we're trying to break this loose here too. Once you've got it off of the injectors, just work it up and out of the vehicle. Remove the injectors by pinching the tabs together and sliding them out. Just go around and undo all eight injectors this way. Once you have all your injectors unplugged, take a small flat blade and pry out the bracket. You may have to rotate the injector lines to clear the bracket. Remove the assembly from the vehicle.

Here we have our old part that we removed from our vehicle, and our new part from 1AAuto.com As you can see, there are some major differences between these parts and that's actually a good thing. We are updating our truck with this new multi-port fuel injection style injector manifold and replacing our old CFI or Central Fuel Injection manifold that we removed from the vehicle. The major differences you'll notice here are the nozzles and the electrical connectors at the nozzle. That's because this is actually a fuel injector down here instead of spraying fuel from the center portion and then out to the ends, we're spraying it directly from the end, which gives us more precise fuel injection as well as better fuel delivery and atomization of the fuel, which all leads up to a smoother, more efficient engine. If your old system has gone bad or you simply want to update your truck, this new part from 1A Auto is going to go in direct fit, just like your original equipment and fix you up right.

Install your new multi-port fuel injection retro-fit. These are going to be a little tricky because the new lines haven't been positioned and they're still pretty rigid. Snap the manifold back into its retainer, and then we're going to set this up so this goes two and four here for the first two. This is cylinder two and four. We're actually going to put in number four first. You want to be very careful with these. Don't force anything because you could risk kinking a line. You don't want to do that. Install it fully. I tucked number two under number four. In reality, you're going to want to install number two first then number four over it. Same concept. Nice and easy here.

We then have cylinders one and three. It goes three, one from where you're looking. Carefully position these. Cylinder one is the first opening on the driver's side or bank one. And then cylinder three will be the one right behind it. The backside of this injection manifold is going to go eight, six, five, seven. As I'm sure you can guess, we have six, followed by eight all the way at the back on the passenger side. We'll install that. Number six first, followed by number eight. We'll then put in number five on the inside, followed by number seven all the way in the back. Double check that the manifold is in place and we'll reinstall our upper intake.

Wipe down the gasket surface with a clean rag or paper towel that you've sprayed some cleaning solution on. I like to use brake parts cleaner. You could also use carburetor cleaner or a throttle body or fuel injection type cleaner. Really any kind of solvent that'll work to get that dirt and oil up and off of there. The style of gasket used on these upper intake manifolds was originally intended to be reusable. However, our truck has about 160,000 miles on it, so we'd rather just replace the gasket than risk it. We recommend you do the same thing. If your gasket has been changed more recently on your upper intake manifold, you may get away with reusing it, but we do strongly suggest replacing this part while you have it apart.

Reinstall the upper intake manifold. Be sure to move all your wiring harnesses, lines, brackets and anything else you had to loosen or remove. Now, it is a little tricky to get the upper intake manifold to sit down onto the plug for the spider. Just make sure that you work it on there. It will sit down. You do have to give it a little bit of force. Take your time, work it down onto that gasket, and make sure that it seals fully before attempting to install the bolts. Otherwise, you risk damaging the manifold.

We're going to start in the 12 o'clock position on our intake manifold and work our way around clockwise. You may choose to do this differently, but we do need to get all of our bolts and any brackets that these bolts secure in place before torquing our intake manifold. I just have the 10 millimeter socket on an extension here just to help me get some of these bolts started in. It is a little tricky to line this up, so you do want to make sure that you take the time to get all the bolts started before tightening anything down. Otherwise, you may find yourself loosening hardware to get other pieces in place.

Be sure to install any brackets you removed. Once you've got all your bolts in and started, go ahead and bring them down until they just touch the intake so we can begin our torque sequence. We'll torque the intake manifold following the proper torque sequence in two passes. The first pass will be 44 inch-pounds or five newton meters, and the second pass will be 88 inch-pounds or 10 newton meters.

Reinstall any brackets that sat over the studs on the upper intake. Like here, we have the cylinder head temperature sensor. Also, reinstall this bracket over the ignition coil and control module.

Reinstall the fuel lines. Reinstall the hold down bracket and the two, eight millimeter nuts. Reinstall the fuel lines by getting the flare nuts lined up and threaded in, and tightening them down with a 16 millimeter wrench. You can then reinstall the 10 millimeter hold down bolt to the fuel line bracket. Make sure you reinstall the cap on the fuel straighter valve.

Reinstall your distributor cap. The two T-20 torque screws. I recommend doing the one in the front first because you can see it and line everything up. It's easier to install the back one after that.

Reconnect all of your electrical connectors. Be sure to snap back all of the loom retainers as well after you've connected the closest pieces to make sure that they all stay the same length. Don't forget to snap the safety back into the connector on the fuel injector manifold. You'll then want to reconnect any vacuum or breather lines that you unplugged.

Reconnect the brake booster hose at the back of the intake and compress the clamp with a pair of pliers, and slide it back into place.

Reinstall the throttle cable bracket with the 10 millimeter bolt securing it to the throttle body and the 10 millimeter nut on the bottom where it slides over the stud for the intake manifold. We'll then tighten those down with the 10 millimeter socket and ratchet. To reconnect the throttle cable, open the throttle manually and rotate the cable so it fits through the slot. Push the cable end in and set it into its guide, and lift up a little and snap the clip for the cruise control cable back onto its tab.

Reinstall the intake tube by hooking the tab over the front of the throttle body and setting the back into place. Reinstall the thumb screw on the stud. Reinstall the tube into the filter as well as locking it into the back of the air box. Reconnect your mass air flow and intake air temp sensors. Drop the lid black into place. Secure the tabs. Install the breather line and you're good to go.

Thanks for watching. Visit us at 1AAuto.com for quality auto parts, fast and free shipping, and the best customer service in the industry.

Tools needed for replacement:

    General Tools

  • Pick

  • Materials, Fluids, and Supplies

  • Paper Towels

  • Pliers, Cutters & misc Wrenches

  • Channel-Lock Pliers

  • Ratchets & Related

  • Ratchet
  • Torque Wrench
  • Socket Extensions

  • Screwdrivers & Related

  • Flat Blade Screwdriver

  • Sockets - Metric

  • 8mm Socket
  • 10mm Socket

  • Star Drivers & Sockets

  • T20 Driver

  • Wrenches - Metric

  • 16mm Wrench

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