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4.3 Vortec Swap

Discussion in 'Flat Fender Tech' started by coby61, Aug 20, 2005.

  1. Aug 20, 2005
    coby61

    coby61 Stupidiotic Member

    Prunedale CA
    Joined:
    Mar 10, 2004
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    388
    I have been planning on using a 1990 4.3 TBI engine for the 3b but now I am thinking about going to a 00-02 Vortec becase I can buy one out of a wrecked truck complete for cheaper than I can rebuild this one. So I was wondering if anyone had any advice on either.
     
  2. Aug 20, 2005
    Spicolli

    Spicolli jeep geek

    So. Cal.
    Joined:
    Dec 23, 2004
    Messages:
    188
    go with the Vortec :) . and sale the other engine!! Just my 0.02
     
  3. Aug 21, 2005
    DanStew

    DanStew Preowned Merkin salesman Staff Member

    Lexington, South...
    Joined:
    Sep 22, 2002
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    4,585
    yeah go vortec, i have heard nothing but good things bout them
     
  4. Aug 21, 2005
    Ledge

    Ledge Member

    Old Town, Maine
    Joined:
    May 5, 2004
    Messages:
    72
    Go vortec over old 4.3. It'll require a little more electrical work and fabbing as far as your fuel system goes, but it should be worth it in terms of power and driveability.
     
  5. Aug 21, 2005
    Boyink

    Boyink Super Moderator Staff Member

    Tulsa, OK
    Joined:
    Sep 20, 2002
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    If you can dig up John Nutter (JNutter here on the board, I think) shoot him a PM...he's done the TBI swap, and IIRC was working on a Vortec swap on another Jeep.

    IMHO I'd stick with the TBI...but that's only because I'm getting ready to swap all the TBI stuff onto SSDutch and can use all the help I can get...:D
     
  6. Aug 21, 2005
    mruta

    mruta I drank with Billy!

    Downers Grove, IL
    Joined:
    Sep 22, 2002
    Messages:
    422
    I'm putting a TBI 4.3 into my Jeep. I don't dislike the Vortec engine but it is much more involved than putting a TBI engine in. 1996 and newer engines require a LOT more in terms of electronics. You may have to have the ECM reprogrammed as well. If you don't, you'll have to run with a catalytic converter or you'll have the check engine light on constantly (may not be a problem to you though). The achilles heel of the Vortec 4.3 seems to be the fuel system. They will NOT run if the fuel pressure drops below 52PSI. You've got to have a good fuel pump. Also, the poppets tend to get stuck over time causing drivability problems and no-start conditions.

    If I came across one cheap (almost free), I'd use a Vortec 4.3 in a heartbeat. Till then, I'll be sticking with one of the two TBI engines I got for free. :D

    Good luck!
     
  7. Aug 21, 2005
    jd7

    jd7 Sponsor

    Nacogdoches,Texas
    Joined:
    Mar 30, 2004
    Messages:
    1,745
    I did a swap a few years ago using an OBDII system. Found the problems mruta mentioned. It is possible to do, I laid my harness out and went through and "thinned" the stuff out of it I didn't need. Didn't run cat and didn't use the "check engine light" but kept the diagnostic port though. I didn't have to reflash the computer on that application but have since done one that I had to send the 'puter off and have it reflashed. I ended up only using specific funtionwires(injectors, crank sensor, map senser, etc. And ended up needing three or four hookup wires fuel pump, tach, power wire one maybe two other can't remember now. Oh found that ford frame mounted fuel pump from I think Taurus works and provides adequate pressure. Now neither of the ones I did were for a Vortec 4.3 but they were OBDII which I'm told power up pretty much the same. So make sure you get the 'puter and as much of the harness as possible. You'll use very little of it but the more you get the less chance you have of ending up not having something you need. hth
     
  8. Aug 22, 2005
    DoubleK

    DoubleK New Member

    Lubbock, TX
    Joined:
    May 4, 2004
    Messages:
    41
    I'm working on a 2000 4.3 Vortech in my '72. It's been a challenge electronically. That year is equipped with VATS or some variant of an anti-theft system that has the ignition switch components in the column talk to the body control module that sends a password to the ECM, I had a guy try to bypass that and it didn't work. He then found me an older ECM to use and I'm dealing with problems getting the transmission to shift now.
    Other issues included all the injectors not working due to sitting too long with old gas in them. At $60/each that set me back a while on funds.
    I got the gas tank and fuel pump from the donor vehichle and cut the flange out of the plastic tank and epoxied it into my steel CJ tank after cutting the opening in the steel tank a little larger.
    Overall I like the Vortech and still think it's the way to go, but there are quite a few obstacles that accompany the newer technology.
     
  9. Sep 19, 2005
    jnutter

    jnutter New Member

    Minnesota
    Joined:
    Mar 20, 2004
    Messages:
    39
    I haven't been around here for a while, but I'll throw in my $.02

    I don't know anything about swapping an OBDII era vortec. Sorry. I can't afford engines that are that new :) As such, the following comments are slightly off topic for this particular post:

    As far as the older stuff goes, pre-OBDII Vortec 4.3 and TBI 4.3 have virtually the same wiring and sensor package. The biggest difference is that the pre-OBDII CPI Vortecs have only one injector while the TBI has two. That's right folks, a vortec 4.3 from a '93 S-10 is marginally simpler than a TBI 4.3 from a '93 S-10 :) You will need a higher pressure fuel pump for the Vortec, the vortec throttle cable is longer and and you will most likley use a cone type air filter on a VPI Vortec - but beyond these three things the swap is virtually identical. It's really easy to pull a TBI 4.3 and drop in a CPI vortec for an additional 45 hp. By the way, low end torque seems to be just as good with the CPI engine. I have used the stock harness on both, and the wiring works the same. The harnesses are very similar.
     
  10. Sep 19, 2005
    Boyink

    Boyink Super Moderator Staff Member

    Tulsa, OK
    Joined:
    Sep 20, 2002
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    *hands over ears* lallalallalalalallalal :D
     
  11. Sep 19, 2005
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    Sep 23, 2002
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    I'd go with the TBI over the Vortech because of the injector problem prone CPFI system used. The TBI systems rarely have injector issues if well maintained whereas the Vortech's plug up/stick. They are notorious for this problem and not cheap to replace. I had the option of going both ways and decided TBI due to simplicity, cost, and availability of parts on every street corner parts house. Nickmil.
     
  12. Sep 19, 2005
    coby61

    coby61 Stupidiotic Member

    Prunedale CA
    Joined:
    Mar 10, 2004
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    nickmil
    decided to go with a internal balance 1990 TBI motor to make things simple. I canget everything to replace easy and Howell uses alot of the same components for they're injection.

    Coby
     
  13. Sep 20, 2005
    jnutter

    jnutter New Member

    Minnesota
    Joined:
    Mar 20, 2004
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    Clogging injectors is not comon, but it can happen in any EFI system. If you do manage to clog one in a CPI system, rest assured that whatever clogged it would have also clogged the injectors in a TBI system. Both have a screen inside and you would have to disassemble either type of injector to clean it. Both are cleanable. There's a write up on disassembling CPI injectors to clean the screen somewhere on S-series.org. It's no worse than working on TBI injectors.

    The problem with the CPI injection system is the pressure regulator. The pressure regulators leak when they fail, and it's going to happen to al the stock CPI regulators eventually. Lindertech sells a heavy duty replacement injector for $100 that solves the problem premanently.

    The other failure point is the 'nut kit' that routes the fuel from the external lines to the injector/regulator assembly. These do fail from time to time, but when I see them in the U-pull yard they are almost always intact - unless someone cut it to get the injector out.

    I've done plenty of work on both TBI and CPI. The systems are more alike than not.
     
  14. Sep 20, 2005
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
    Joined:
    Sep 23, 2002
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    12,529
    It's not the screen that's problematic in my experience. It's the nozzles themselves. The design is such that the CPI nozzles clog more than the TBI nozzles due to buildup. The local GM training center has even commented about some of the issues they've encountered with the CPI design. Don't get me wrong, I like the CPI system, it's much more efficient than the TBI system. But it MUST be maintained PROPERLY like any system (which the vast majority DON'T) or it can be expensive to repair and can be much more problematic and more difficult to service for the the average guy who doesn't have a garage full of special equipment. Most people looking to put a 4.3 with fuel injection are most likely looking at installing a used engine, or at least an engine with used fuel injection. The TBI is a better swap in this case as again, they are less problematic than the CPI systems, especially when they've been sitting in a garage corner somewhere for a while. Generally, they are cheaper to purchase as well. :stout: Nickmil.
     
  15. Sep 20, 2005
    mruta

    mruta I drank with Billy!

    Downers Grove, IL
    Joined:
    Sep 22, 2002
    Messages:
    422
    What Nick said x2.

    The fuel system is the weak point of the Vortec engine. Not only is clogging an issue but fuel pumps are another can of worms...
     
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