New plugs and wires, what a difference!

Discussion in 'Maintenance & Upkeep' started by kinson33, Dec 9, 2012.

  1. kinson33

    kinson33 Member 1 Year 100 Posts

    Avalanche was idling very roughly, knew it was due for maintenance but I figured it didn't like the cold weather too much. Close enough to 100k so I bought some new plugs from NGK, iridiums of course, and MSD wires.

    After reading through many forums on tips and tricks to getting the wires off easily I was able to do all 8 plugs in 45mins, feelin good about that.

    Runs like a dream now paired with the new ebay intake. Here's what the old plugs looked like:


    - - - Updated - - -

    Only thing I wish I did differently was order the Red MSDs instead of black :cool:
  2. Bighornkid

    Bighornkid Rockstar 100 Posts

    Glad it helped. I'm getting ready to do my Yukon XL with 8.1L. AC Delco only makes platinum plugs for mine. I got the red MSD's. Hope mine can be done as fast.
  3. kinson33

    kinson33 Member 1 Year 100 Posts

    Don't use iridiums in that beast?

    I reccommend a short handled ratchet, and I would have two sockets. One with the pivot and one regular size for the tight areas. Don't forget the dielectric grease

    - - - Updated - - -

    Correction....I put in Autolite's not NGK
  4. Bighornkid

    Bighornkid Rockstar 100 Posts

    All of the smaller motors switched to iridiums. I still have to use platinum. Thanks I'll have to get the grease.
  5. 1993gmc

    1993gmc New Member

    Glad it's running good.

    Im running the whole MSD set up dizzy, box, just all of it and I have way over 100K on NGK's plugs and my gap the last time I changed them out were three times open than stock im proud of my baby as you are keep on truckin bud. One can't beat a GM truck. :happy:
  6. Skippy

    Skippy Member 2 Years 100 Posts

    Plugs are one of those things that when they're old and worn, you can put a $0.80 copper plug in and see a performance gain! My favorite advertising is for the high end plugs that promise "you'll feel the difference or your money back." DUH. :p

    First thing I do when I see a vehicle with 80K+ is check those plugs for wear. Wires are a bit more finicky, harder to tell with those, but when I do 100K services, I get them replaced as a matter of course.

    Glad to hear things are improved on your system. If you're interested in dropping several hundred MORE dollars into your vehicle for yet even more returns of power... Try replacing your fuel injectors. Folks often forget that fuel injectors actually wear out, rather than just 'fail.' Injector nozzles widen (normal wear and tear, won't throw a code, just have some power loss) and the valves start leaking (only will throw a code when the mixture gets so rich the system can't compensate). The result is poor combustion in the chamber even though the injector is operational. And when you've got widened ports (just a result of time and heat), the spray isn't as atomized as is necessary for close to perfect combustion. Widened ports cannot be "cured" with fuel injector cleaner... only clogged ports. :)

    I've seen many engines go out because of bad injectors (even though they were "firing"). When your vehicle hits the roughly 140K plus miles mark, if you plan on keeping it another 100K, it's not a bad idea to swap 'em with new ones. In the long run a few hundred bucks and 2 hours is often worth the motor. This doesn't even include the roughly 1-2MPG restoration...

    Remember, though, you'll never "gain" HP from new plugs or wires, only restore what has been lost over the wear-life of the equipment. A spark is a spark, and combustion is combustion. If you can get the fuel/air to combust properly, no amount of "stronger spark" will assist. Those high performance application plugs and wires are to ensure the plugs GET a spark during non-normal conditions. Once spark and combustion occurs. Bingo, power!

    Cheers! and happy new year!

    2 people like this.
  7. kinson33

    kinson33 Member 1 Year 100 Posts

    Absolutely right, only restoring what was lost. Haven't thought about injectors but that wouldn't be a bad idea. Is that something I could take care of with basic tools or an experts job?
  8. Skippy

    Skippy Member 2 Years 100 Posts

    It's you're lucky day. I was feeling in a writing mood. :) The first time you do this, it'll probably take about an hour and a half, because you'll be slow and careful. This generally takes me about 30 to 45 minutes to do a full injector swap. TOTALLY worth your time, btw, as the dealers will charge upwards of $1200 to do this! Usually I only need one or two sockets (8mm and 10mm), but sometimes I find an engine that needs something else. For the most part, though, a simple socket set is all that is needed. Nothing special here.

    Ease of Repair:
    Easy to Medium
    Personally, I think it's easier than many spark plug replacement jobs, because, generally, the injectors are more accessible.

    Rags, clean motor oil, new injectors, Socket set

    Caution: As with any fuel related repair, make sure you do this in a WELL ventilated place, and no smoking while working on the Truck! It also helps to do this on a CLEANED engine (no gunk getting into the injector slots), and on a cool engine (no burned hands).

    Start by depressurizing the fuel system. If your truck is equipped with a fuel safety cutoff switches, find it and pull the electrical plug from it. This will disengage the fuel pump. Then try to start the engine (it will turn-over, but not start). This will pull any fuel from the lines and depressurize them.
    Disconnect the battery.

    If you don’t have a fuel safety cutoff switch, you can depressurize the line by finding the pressure check valve (usually on top of the rail) and depressing the valve. This will spray fuel everywhere, though, and is messy. If you have a fuel pressure tester, it’ll come with a valve checker and hose for this purpose making it far less messy. It’s not necessary though.

    Last resort is to pull a fuel line, that’s REALLY messy. Make sure all fuel is mopped up and dry before proceeding. No sparks here!

    Next, pull any components that restrict access to the fuel rail on the engine. On a V-8 you’ll need to do this for both sides of the engine, as the rails will be on both sides. Most Chevy trucks will need the following removed: engine shroud, air intake, vacuum tubes, electrical plugs and bolt-on engine accessories.

    Next, disconnect the fuel rail bolt securing the rail to the intake or engine.

    At this point you’re ready to pull injectors (not so bad, huh!) Basically, since you’re doing all the injectors, just pull the fuel rail directly away from the tops of the injectors (they’re just held on with O-rings). You may need to rock the rail slightly. The rail will pop right off all four injectors will a little pulling.

    Remove the injector from the engine by grasping the injector head and pulling it directly away from the engine. You may find again, that it needs a little rocking.

    Once pulled, make sure that each injector has the O-ring on the bottom and top. Otherwise, check the rail or hole. The O-rings are larger than the hole in the engine, so there’s no worries about it slipping down inside, but occasionally they do remain in the slot.

    On the new injectors, check to see if they come with pre-installed O-rings. They should. If not, you’ll need to get O-rings on them (they’re cheap, btw, but you’ll need to get new ones from the auto parts store..> DO NOT USE OLD O-Rings as they’ll have micro-tears or will be hardened, not making a great seal. In fact, it’s a good idea any time you remove the injectors from the rail or engine to replace the O-rings).

    Before putting the O-rings on, lubricate them with new motor oil. The goal is to ensure there are no micro-tears in the O-ring that will cause leaks later. The O-rings are fairly flexible and can be either rolled onto the injectors or pressed into place. If the injectors come with the O-rings on, lubricate the O-rings with motor oil while the O-ring is in place.

    Put the injector back into the engine by pushing it nozzle first into the hole. Rock it slightly. You’ll feel a slight “pop” as it seats. This is normal. When correctly seated, the injector will resist light attempts at removal. Seat all four injectors in the engine on each side before attempting to connect the rails.

    Connect the rails by seating all four injectors under the ports at the same time, then just press downward. You’ll likely have the same popping feeling again, and as with the engine, properly seated injectors will resist removal.

    Reconnect the fuel rail retaining bolt or screw, and replace any accessories, intake, vacuum tubes, etc. Don’t put on the engine shroud just yet.
    Reconnect the fuel-safety cut-off switch, if you used this method. Reconnect the battery.

    Prime the fuel system by turning the ignition key to the “start” position a few times (with several seconds in place). You’ll hear the fuel pump prime the lines. Do this at least 3 times to pressurize the fuel lines.

    Inspect the engine compartment for fuel leaks at the injector rails. If you have one, an O-ring isn’t properly seated. Remove the rail and replace the O-ring (as it’s likely been damaged in the process). I’ve never had this occur, but I always check just in case. No use having an engine compartment fire over something as silly as a badly seated O-ring!

    Install the plastic engine shroud at this point (you needed to keep it off to see the rails) Close the hood and enjoy!


  9. Bighornkid

    Bighornkid Rockstar 100 Posts

    Very good writeup, Skippy.
  10. kinson33

    kinson33 Member 1 Year 100 Posts

    Good stuff, any chance you have pictures from one of these jobs? Think I might take this on along with the floor cut out for the fuel pump if I can get a more experienced friend to come by in case I run into any issues.

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