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Fuel Injection Problem???NEED HELP

Discussion in 'Other Rides' started by TrcksR4ME, Apr 3, 2002.

  1. TrcksR4ME

    TrcksR4ME 1/2 ton status

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    Well, I hate to ask this on this site, but my 89 Isuzu Trooper (Daily driver) has this problem where when you start the car it will not idle and stay running. It is a 2.5 4 cylinder, FI.

    What happens is it turns over and starts, but immediately quits running. If you push on the gas nothing happens, it still stalls. BUT when I press on the gas and hold it to the floor prior to starting and as I am turning it over it will start and run-as long as you rev it to over 3000rpm as you are starting. In general it idles like sh*t. Has 175000 miles on it, so it could be a lot of things I'm thinking.

    Anyone have any ideas?? I know Isuzu's (Itscrewsyou /forums/images/icons/smile.gif) aren't the forte of this site, but maybe the principals of engines and fuel injection cross-over? I need help ASAP, this thing is my transportation for school and work.

    THANKS in advance
     
  2. 55Willy

    55Willy 3/4 ton status

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    fuel pump?
     
  3. TrcksR4ME

    TrcksR4ME 1/2 ton status

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    I dont think so, it has been replaced in the last few years. And the thing does run once you get it started.

    I don't know squat about fuel injection, but remember hearing something before about how it runs in a "closed loop" at higher RPM's? Dont know what part of the system that refers to, but the only way it starts is by reving it above 3000rpms initially. There are so many different things with fuel injection, I am completely lost.

    We also took it into the shop a while back for this problem, and they just said it needed a tune-up. But it kept doing the same thing even after they worked on it. It has been like this since December, and it is really annoying.
     
  4. BurbinOR

    BurbinOR 3/4 ton status

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    I'd check fuel pressure, sounds like fuel pump. Clogged fuel filter..............try those first, and let us know.
     
  5. TrcksR4ME

    TrcksR4ME 1/2 ton status

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    I'll see what I can see...the fuel filter was supposedly just replaced in December by the shop we took it too when we first started having problems, but I am gonna take a look and verify this.

    These problems started showing up after i installed a subwoofer in the vehicle. Could the vibration from the bass have stirred up crud from the bottom of the gas tank and clogged the filter up? Just an idea.
     
  6. I don't think it's the fuel filter. If you think about it, fuel flows at a slower rate at idle, and flows faster at higher rpm's. Usually a clogged fuel filter affects higher speed like highway driving first. I used to work at a shop as a auto technician and from my experiences I would look for a "vacuum leak" first by getting the isuzu running and carefully spraying carb cleaner around all the vacuum connections to isolate the vacuum leak. Does the vehicle idle by itself once it is at full operating temperature? If it happened after you installed the subwoofer, then maybe you have the power cable to the amp located to close to a sensor in the engine compartment? On fuel injected vehicles it is very important not to run electricity next to engine sensors and components. Maybe when you installed the subwoofer, you accidently unplugged some sensor connection or vacuum connection. Look at every thing next to your cables and look for something that came undone.
     
  7. TrcksR4ME

    TrcksR4ME 1/2 ton status

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    It does idle once you get it started, just kind of irratic and low, like 550-600rpms sometimes. I will check around in the engine compartment and see if anything is out of whack. Will wait til a nice day though /forums/images/icons/smile.gif
     
  8. calcide

    calcide 1/2 ton status

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    After you do a complete visual inspection (loose connectors, hoses, whatever), change your fuel filter and buy a pressure gauge and check your fuel pressure.

    Contrary to popular belief, low fuel delivery can allow the engine to start, idle, and run at higher RPMs with no load. The engine needs the most fuel when it is working hard, not when it is cruising at a steady speed or idling. When the engine will start and idle and rev up in neutral, but bogs and dies when you try to acclerate look at the fuel system first. Check the pressure (or have it done) to make sure before you go through the hassle of changing the fuel pump. I don't know how bad it is to do a pump on your vehicle, but on my firebird I had to drop the differential and the exhaust system to get to the tank.
     
  9. ntaj*ep

    ntaj*ep 1/2 ton status

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    Something that will not cost as much and is pretty simple to do, is pull off the intake air tube and clean the throttle plate. Use some intake FI cleaner (its like carb cleaner, but not actually CARB cleaner) it will say fuel injection cleaner on the bottle and fuel injection safe. Use that and a few rags to clean the plates edges and where the plate sits closed in the intake manifold. Also if there is a base Idle screw in the throttle body itself take that out and clean that and the bore it was screwed into. When you screw it back in bottom it out then go 2 turns out. Hopefully that cures your idle problem.
    I think since you say it's been doing this for a while the gunk has been building up for some time until this point. The stereo I think could be an issue in that you could have blown a fuse or your over powering the charge rate of the battery. Before you start I personnally would look at all the fuses, check the EFI ecu for codes (even if the lamp is not on you could have a code, that could solve your whole problem) If no code is found, clean out the throttle body/base idle orfices, and lastly reset your ecu (either pulling a fuse for a curtain amount of time or pulling the battery terminals) I do belive this will solve your issues, or at least point you in the right direction.
     
  10. Nrose07

    Nrose07 1/2 ton status

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    If it were a gm V6 V8 then I'd say carbon chunk is holding the EGR valve open. Isuzu, well not sure, but I'm sure it has to be close to the same.
     
  11. Prembird

    Prembird 1/2 ton status

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    well i had a something like that happen to my tbird... turned out to be a bad idle air control valve causing it.. But and idle and low rpm after warmup it would make a howling noise but that had to do with the supercharger... just a thought.. check into the IAC valve.. there cheap to replace and with that many miles it might have something to do with it...
     

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