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Oh TPI gurus...update and ?'s

Discussion in 'The Garage' started by Hossbaby50, Nov 24, 2003.

  1. Hossbaby50

    Hossbaby50 3/4 ton status

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    Oh TPI gurus...update and ?\'s

    I am close. Here is an update, and I will have questions at the end. I tried to fire my truck last night but no go. The first attempt I started to leak gas out of the top of the injectors and I didn't get it to try and fire. I stopped because I didn't feel like burning my truck and garage down.

    Later I went out to see if I was getting spark. I disconnected the fuel pump power wire and checked for power to the coil (there was) and I cranked and checked for spark at the cylinders. There was.

    I reconnected the FP power I played with the timing some and I got it to try to fire. It would cough and cough as i cranked but no start. It was trying to catch but to no avail. I adjusted the distributor forward and back both ways until it would stop coughing during cranking but it never fired. I am thinking I might be 1 plug off but not sure.

    I set the motor to TDC (or really close) before I reinstalled the cap and wires. I installed the number 1 wire to the terminal on the cap that the rotor was pointing to (or looked like it was), and reinstalled the rest of the wire in order around the cap. So that should mean I should have the order down or only be 1 plug off correct?

    ...
    The second go around I didn't get fuel leakeage from the injectors like I did the first time. Why is this. I did more the one injector that was leaking badly around a little. Did they just need to seat or why didn't they leak the second time?

    How exactly can I test to see if the fuel injectors are pulsing? How do I hook up a meter to them to see if they are getting power without frying them? (I have a multimeter)

    I know there is something on the fuel rail (I think near the regulator) that I should be able to check and make sure the rail is being pressurized. It is a pressure relief isn't it? Where is this?

    Any other ideas? Anything I should be looking for and check? Thanks

    Harley
     
  2. Chris Demartini

    Chris Demartini 1/2 ton status

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    Re: Oh TPI gurus...update and ?\'s

    <font color="blue">The injectors pulse WAY too fast for a multimeter to detect. You need to get a special injector test light, I got mine at autozone for $3. Also, make sure all your ignition hot circuits are powered in start as well as run.
     
  3. HarryH3

    HarryH3 1 ton status Author

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    Re: Oh TPI gurus...update and ?\'s

    Ask 'em for a noid light for your particular TPI setup. It will plug right in to the injector connector. /forums/images/graemlins/cool.gif
     
  4. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Re: Oh TPI gurus...update and ?\'s

    This will only tell you if you have a signal to the injector, it will not tell you if the injector is pulsing or not. There is always the remote possibility that there is a bad injector, but not likely.
     
  5. HarryH3

    HarryH3 1 ton status Author

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    Re: Oh TPI gurus...update and ?\'s

    Yeah, but he has EIGHT injectors. It's highly unlikely that all 8 would be bad. /forums/images/graemlins/wink.gif The noid light will at least let you know if the ECM is even telling the injectors to fire. If the ECM came from a VATS equipped ride, then the injectors won't be getting any signal until the VATS input sees the correct data. /forums/images/graemlins/frown.gif
     
  6. BobK

    BobK 1/2 ton status

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    Re: Oh TPI gurus...update and ?\'s

    Is it a MAF or Speed Density system?If it's a S.D. make sure the MAP sensor has manifold vacume to it and the wire harness is connected.
    I mention this as I forgot to reconnect mine while doing some work on my blazer.It would want to start but never would.
    Dumb...I know. /forums/images/graemlins/crazy.gif
     
  7. BurbinOR

    BurbinOR 3/4 ton status

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    Re: Oh TPI gurus...update and ?\'s

    Regarding the fuel pressure - there's a Schrader valve at the rear on the passenger side (by the distributor on the fuel rail) that you check your can check if you have fuel pressure at - unscrew the cap and bump the little valve thingie (nice terminology, huh /forums/images/graemlins/grin.gif) WITH A RAG over the top to catch the fuel. I bought a fuel pressure gauge with hose from www.tpis.com - mine's for sale now that I think about it (no longer have TPI) so let me know if you're interested.

    BTW - did you put the injectors in yourself? If so, did you use some kind of o-ring lube (even vaseline works)? That may have been the cause of the leak, or it may have been they hadn't been fired in a while and the o-rings are a bit dry..........not good.
     
  8. Hossbaby50

    Hossbaby50 3/4 ton status

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    Re: Oh TPI gurus...update and ?\'s

    How much for your gauge?

    I did lube the injectors and they seemed to seat properly. They didn't leak on the second attempts so I think I just had to move them a little to get them to seat totally.

    I am running a MAF setup. Is there any vacuum sources that absolutely need vacuum to run? The only thing I have hooked to a vacuum port right now is the fuel pressure regulator.

    My system was not equipped with VATS so I don't think that is the problem. Thanks everyone. I will be diving back into this more after I get back from elk hunting this weekend. Thanks.

    Harley
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

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    Re: Oh TPI gurus...update and ?\'s

    Did you ever pull the injectors from the fuel rail?

    I did on mine to clean them up/check condition of the o-rings, and ended up replacing every single o-ring on the system, to include the fuel lines. Every one was ripped/torn/damaged in some way (plus hard from age) and would undoubtedly have caused at least one leak had I reinstalled them like that.

    Just a heads up, I doubt you want to dig back into that, but if you had a leak from the get-go, and they are old seals, I wouldn't feel safe until I got them replaced.

    They are special seals (hydraulic places won't have them from what I found), and GM is pretty pricey on them though. I may be able to get them for a decent price...
     
  10. Hossbaby50

    Hossbaby50 3/4 ton status

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    Re: Oh TPI gurus...update and ?\'s

    I replaced the orings that are on the injectors that seal it to the manifold.
     
  11. HarryH3

    HarryH3 1 ton status Author

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    Re: Oh TPI gurus...update and ?\'s

    There's another O-ring at the other end of each injector. /forums/images/graemlins/shocked.gif There's a little locking ring that holds the injector into the fuel rail. BTW, it's the end up at the fuel rail that is constantly exposed to full fuel pressure. The O-ring at the manifold end is basically to prevent vacuum leaks, as that end of the injector just sprays small amounts of fuel into the intake.
     
  12. BurbinOR

    BurbinOR 3/4 ton status

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    Re: Oh TPI gurus...update and ?\'s

    Harry's right as usual. Did you use an o-ring lube on them? Vewwwy important............. /forums/images/graemlins/laugh.gif
     
  13. Hossbaby50

    Hossbaby50 3/4 ton status

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    Re: Oh TPI gurus...update and ?\'s

    Yep, Harry is usually right (can't recall him being wrong). After meeting him and talking to him you know that he is very informed and knows what he is talking about.

    The injectors were installed in the fuel rail when I got the system. All the orings were replaced by the PO less then a year ago so I don't think the orings should be bad. (PO is a member here and is upstanding). I did use lube on the lower orings when I installed the rail onto the manifold. First I didn't and they wouldn't seat right, then I did and they slipped right in.

    I didn't have the problem the second time I went to start my truck which makes me wonder that when I moved them around they didn't seat totally. The first time the injector for my #1 cylinder had a big puddle of gas on the top of the manifold. I cleaned it off and the second time after I moved the injector around some it didn't have a puddle or leak from what I could see.
     

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