***Login to the Forum here ***

Support FSC and see no ads! - Click Here
Page 1 of 3 123 LastLast
Results 1 to 20 of 46

Vortec 7.4 fuel injector and fuel pressure replacement / upgrade - with pics

This is a discussion on Vortec 7.4 fuel injector and fuel pressure replacement / upgrade - with pics within the Big Blocks forums, part of the Performance category; A quickie editing of an older post of mine, to start off the new Big Block forum: The subject is ...

  1. #1
    Loves GMT400 haters someotherguy's Avatar
    Join Date
    Aug 2005
    Location
    somewhere else
    Posts
    11,099

    Vortec 7.4 fuel injector and fuel pressure replacement / upgrade - with pics


    Support FSC and see no ads! - Click Here
    A quickie editing of an older post of mine, to start off the new Big Block forum:

    The subject is a 1996 Vortec 7.4 with 240K hard miles on it, transplanted into a 1994 3500HD. It's had a whole list of problems that previously were just annoying, but recently got bad enough to cause major grief.

    It's had the hot restart issue where it cranks forever then blows out a bunch of unburned fuel, typically leaking injectors or bad fuel pressure regulator. I picked up a Standard Motor Products # PR217 regulator from Summit - made in USA. Got a set of Bosch injectors that are a bit of an upgrade over the stock Delphi Multec design; Bosch # 0280150973 from Five-O Motorsports. Plenum gaskets and new fuel rail O-rings round out this segment of the job.

    Fuel injectors: first big hassle was getting the EGR tube off the plenum; they tend to seize, and the backup nut on the fitting is very slim so you don't have room for two large wrenches. Used some PB Blaster, a Channel-Lock brand skinny profile adjustable, and a 1-3/8" on the coupling nut - using a 2x4 block of wood on the valve cover to let the Channel-Lock wrench shove against. (Some anti-seize lube on the fitting is a great idea for reassembly.)


    Simple to get the plenum off; just a bunch of wiring to disconnect and then 8 bolts come out, it lifts right off. Helps to tie-wire a bunch of junk out of the way so you have a clear path to remove.


    COVER THE PORTS RIGHT AWAY; you don't want anything falling down in there at all! I used a paper towel with brake cleaner to get any oily residue off the surface first, so the tape would stick:


    To disconnect the harness from the injectors, the round wire part of the clip pushes towards the connector; you can squeeze it with your index finger and thumb, and lift it off. Once they're all disconnected, unhook the fuel supply and return lines from the fuel rail (helps to remove the distributor cap for working room.) Then unbolt the fuel rail completely from the intake. Gently pry the injector out of the intake with a screwdriver if necessary; the O-ring will have it kind of tight. The rail comes out with all the injectors attached. Take care not to knock any crud into the holes in the intake for the injectors.


    Here's the rail with the injectors removed; getting the hold-down clip off is a little tricky as they're shoved down over plastic nubs in the rail. I used a small flat screwdriver to go under them and carefully twist the tangs away from the plastic nub, working them up the nub as I went. The regulator has been removed too; takes snap ring pliers to get it out. Be sure both its O-rings come out too; large and tiny.


    When removing the injectors be sure to get each O-ring out of the fuel rail with a pick. Here's the old injectors with the O-rings popped back on so I can be 100% sure I have them out of both the fuel rail AND the intake. Note the regulator doesn't have its smaller O-ring in place; I hadn't picked it out of the fuel rail yet. You can also see the one plastic nub I broke for the injector clip.


    Wipe a small amount of clean motor oil on each O-ring where the injectors go into the fuel rail, before installing. I did the same with the FPR O-rings. You don't want to tear any of these; by the time it's all assembled and you discover you have a high pressure fuel leak, you'll be pissed. I left the protective caps on the new injectors until it was time to reinstall the fuel rail.


    Here's a repair I did with two zip ties for the nub I broke. It's on an injector right next to a fuel rail hold-down bolt so I'm not worried, plus the zip ties held it very well, looped through the clip.


    End result is the truck now starts up great every single time, cold, hot, warm, doesn't matter - no more long crank times and no more sputtering to life with a black cloud of unburnt fuel. Power level is good and this is all on the stock tune; no other changes needed.

    Richard

  2. #2
    SRB
    SRB is offline
    Boult
    Join Date
    Nov 2011
    Location
    Fort Davis TX
    Posts
    17

    Re: Vortec 7.4 fuel injector and fuel pressure replacement / upgrade - with pics

    Great info. Would this be the same procedure for same problem on 99 old body style 454.

  3. #3
    FUBO AnotherMtlHead's Avatar
    Join Date
    Feb 2010
    Location
    Western NY
    Posts
    48

    Re: Vortec 7.4 fuel injector and fuel pressure replacement / upgrade - with pics

    Quote Originally Posted by SRB View Post
    Great info. Would this be the same procedure for same problem on 99 old body style 454.
    Yep :)

  4. #4
    Loves GMT400 haters someotherguy's Avatar
    Join Date
    Aug 2005
    Location
    somewhere else
    Posts
    11,099

    Re: Vortec 7.4 fuel injector and fuel pressure replacement / upgrade - with pics

    Same procedure on any year of the L29 Vortec 7.4, 1996-2000, and it might be the same or close enough to same on the L21 too but don't know for sure. Would be interesting to know if the same injectors would be appropriate for the L21.

    Richard
    Last edited by someotherguy; 12-06-2011 at 01:52 PM.

  5. #5
    Registered User 454cid's Avatar
    Join Date
    Mar 2003
    Location
    West Michigan
    Age
    41
    Posts
    4,692

    Re: Vortec 7.4 fuel injector and fuel pressure replacement / upgrade - with pics

    Quote Originally Posted by someotherguy View Post
    Same procedure on any year of the L29 Vortec 7.4, 1996-2001, and it might be the same or close enough to same on the L21 too but don't know for sure. Would be interesting to know if the same injectors would be appropriate for the L21.

    Richard
    2000........ unless the 454 went another year in the medium duty trucks, but I'd assume they went to the 8.1L just like the 3500HD did.
    454cid
    1999 K3500 RCLB

  6. #6
    Loves GMT400 haters someotherguy's Avatar
    Join Date
    Aug 2005
    Location
    somewhere else
    Posts
    11,099

    Re: Vortec 7.4 fuel injector and fuel pressure replacement / upgrade - with pics

    Sorry; I had L21 on the brain since I was thinking about it - and it was allegedly available in 2001 alongside the 8.1. I've corrected my previous post.

    Richard

  7. #7
    Registered User 99urbansuburban's Avatar
    Join Date
    Nov 2011
    Location
    Livermore, Ca
    Age
    39
    Posts
    124

    Re: Vortec 7.4 fuel injector and fuel pressure replacement / upgrade - with pics

    Thanks for the great right with pictures I will be doing mine with a set af fiveomotorsport injectors new fpr and a summit cap rotor wires kit. no special tools needed other than snap ring pliers and a big 1-3/8" open end wrench.

  8. #8
    Loves GMT400 haters someotherguy's Avatar
    Join Date
    Aug 2005
    Location
    somewhere else
    Posts
    11,099

    Re: Vortec 7.4 fuel injector and fuel pressure replacement / upgrade - with pics

    I'd strongly recommend a thin wrench or the skinny Channel-Lock adjustable wrench for back-up on the EGR nut as I showed in the first picture; the fitting will want to come out of the intake and it doesn't have enough width to get a standard wrench on it.

    Richard

  9. #9
    Registered User 99urbansuburban's Avatar
    Join Date
    Nov 2011
    Location
    Livermore, Ca
    Age
    39
    Posts
    124

    Re: Vortec 7.4 fuel injector and fuel pressure replacement / upgrade - with pics

    where is there a good place to get ls1 injectors for a good price, ebay wants to much $

  10. #10
    Loves GMT400 haters someotherguy's Avatar
    Join Date
    Aug 2005
    Location
    somewhere else
    Posts
    11,099

    Re: Vortec 7.4 fuel injector and fuel pressure replacement / upgrade - with pics

    The Bosch I used are $290 for a set of 8 from five-o motorsports, seems like I saw someone post a link recently to them on eBay for a little bit less. I just checked and "fuelinjectorman" on eBay is selling them for $240 a set of 8, just be REALLY careful; I am fairly sure those guys sell "rebuilts" too. The auction says they are brand new just be careful.

    For buying brand new injectors I don't know if you're going to find them much cheaper. Avoid "rebuilts" - the price is tempting but they are not worth it.

    Cruise eBay and search for part # 0280150973 that is the Bosch injector you want, something else to keep in mind is to be sure you're buying them claimed for a Chevrolet application as the O-ring size might not be compatible on the same injector used in a different application. Just a wild-ass guess there but something to consider.

    Richard
    Last edited by someotherguy; 12-08-2011 at 02:56 PM.

  11. #11
    SRB
    SRB is offline
    Boult
    Join Date
    Nov 2011
    Location
    Fort Davis TX
    Posts
    17

    Re: Vortec 7.4 fuel injector and fuel pressure replacement / upgrade - with pics

    What type / brand of fuel pressure regulator do I use. What exactly is a tune. My truck is stock. I have plenty of power. I would like to some how increase the mpg if at all possible along with fixing the hard starts

  12. #12
    Registered User
    Join Date
    Sep 2011
    Location
    East Haddam, CT
    Posts
    35

    Re: Vortec 7.4 fuel injector and fuel pressure replacement / upgrade - with pics

    I am in the middle of this job now. It looks like there are two small bolts that hold the FPR bracket in place? Looks like it's going to be fun getting to the lines to disconnect them from the FPR.

    I noticed when I took off the distributor cap that the rotor had some side to side play, almost as if the two screws holding it down weren't tight enough, but they seemed to be. Seemed weird to me. Thoughts?

  13. #13
    Registered User 454cid's Avatar
    Join Date
    Mar 2003
    Location
    West Michigan
    Age
    41
    Posts
    4,692

    Re: Vortec 7.4 fuel injector and fuel pressure replacement / upgrade - with pics

    Quote Originally Posted by xjhauler87 View Post
    ........I noticed when I took off the distributor cap that the rotor had some side to side play, almost as if the two screws holding it down weren't tight enough, but they seemed to be. Seemed weird to me. Thoughts?
    Are you moving the whole shaft, or just the rotor in relation to whatever it screws to? The distributors do wear. I think the gears tend to wear first/more, but that's from reading, not first hand experience. I went ahead and bought a new Delphi distributor, but haven't installed it yet.

    Since I have a friends Traverse for a few weeks, I might be doing this too, if it will be sunny and warm-ish for a few days.
    454cid
    1999 K3500 RCLB

  14. #14
    Loves GMT400 haters someotherguy's Avatar
    Join Date
    Aug 2005
    Location
    somewhere else
    Posts
    11,099

    Re: Vortec 7.4 fuel injector and fuel pressure replacement / upgrade - with pics

    I won't tell you it was "easy" but it wasn't difficult to get the fuel lines loose and get the rail out. That's no extra bracket for the FPR, it's part of the fuel rail.

    If you can shove the distributor shaft around side to side, it's worn; time for replacement.

    Richard

  15. #15
    Registered User
    Join Date
    Sep 2011
    Location
    East Haddam, CT
    Posts
    35

    Re: Vortec 7.4 fuel injector and fuel pressure replacement / upgrade - with pics

    The rotor was moving in relation to whatever it's screwed to. I'll have to check for shaft play tomorrow.

    Is Delphi the way to go? $$$. How about a reman Cardone? This thing is starting to nickel and dime me.

  16. #16
    Loves GMT400 haters someotherguy's Avatar
    Join Date
    Aug 2005
    Location
    somewhere else
    Posts
    11,099

    Re: Vortec 7.4 fuel injector and fuel pressure replacement / upgrade - with pics

    Rotor is screwed to the shaft. There's no advance weight assembly or anything like that which you would find in pre-computer distributors. If you have lateral movement, there's wear. I'll confess to have used a Cardone distributor in my black 3500HD but I didn't want to; time was a factor as the truck needed to be back on the road earning money immediately and that's all that was locally available.

    If you can wait a couple days for mail order, you can get the Delphi for just a few bucks more than a Cardone will cost you - part # CZ20005 (you double check to be sure before spending your money) is currently $133 through Amazon. Not too many in stock though, 5 right now. The Delphi is miles better than anything Cardone can supply, and at the price difference, a no brainer. The Cardone cost me $125 locally and is just over $100 through Rockauto...

    Richard

  17. #17
    Registered User 454cid's Avatar
    Join Date
    Mar 2003
    Location
    West Michigan
    Age
    41
    Posts
    4,692

    Re: Vortec 7.4 fuel injector and fuel pressure replacement / upgrade - with pics

    Quote Originally Posted by someotherguy View Post
    If you can wait a couple days for mail order, you can get the Delphi for just a few bucks more than a Cardone will cost you - part # CZ20005 (you double check to be sure before spending your money) is currently $133 through Amazon. Not too many in stock though, 5 right now. The Delphi is miles better than anything Cardone can supply, and at the price difference, a no brainer. The Cardone cost me $125 locally and is just over $100 through Rockauto...
    The Cardone's are that much???? Wow! I think I got my Delphi cheaper than what you just mentioned, but Amazon moves their prices around, I've found.
    454cid
    1999 K3500 RCLB

  18. #18
    Loves GMT400 haters someotherguy's Avatar
    Join Date
    Aug 2005
    Location
    somewhere else
    Posts
    11,099

    Re: Vortec 7.4 fuel injector and fuel pressure replacement / upgrade - with pics

    Consider that it comes complete with cap, rotor, and cam sensor - ready to bolt in - and it's hard to believe they sell the thing that "cheap"! It's definitely junk, though; the Cardone that is. I wish that there was time for me to have ordered the Delphi but at the time, every minute that truck was down was a disaster.

    Richard

  19. #19
    Registered User 454cid's Avatar
    Join Date
    Mar 2003
    Location
    West Michigan
    Age
    41
    Posts
    4,692

    Re: Vortec 7.4 fuel injector and fuel pressure replacement / upgrade - with pics

    Quote Originally Posted by xjhauler87 View Post
    The rotor was moving in relation to whatever it's screwed to. I'll have to check for shaft play tomorrow.

    Is Delphi the way to go? $$$. How about a reman Cardone? This thing is starting to nickel and dime me.
    Delphi is OEM. For our GMT-400 trucks buying Delphi, through Amazon, is like buying dealer parts at less than autoparts store prices. The newer trucks don't use as much Delphi, and use a lot of Denso instead.

    I avoid Cardone like the plague.
    Last edited by 454cid; 12-18-2011 at 04:58 PM.
    454cid
    1999 K3500 RCLB

  20. #20
    Registered User
    Join Date
    Sep 2011
    Location
    East Haddam, CT
    Posts
    35

    Re: Vortec 7.4 fuel injector and fuel pressure replacement / upgrade - with pics

    The rotor was moving on the shaft though. It was clear that the rotor was moving in relation to the screws holding it down. Weird. I couldn't find the Delphi's that cheap. The Cardone is $80 at Advance Auto (NOT my favorite place.) If they really can be had that cheap, I suppose that's the route I will take. If I need one at all. I hate junk parts.

 

 
Page 1 of 3 123 LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •