motorheads unite tbi help

Discussion in 'Class A / Diesel Pushers' started by hailo, Aug 1, 2010.

  1. hailo

    hailo New Member

    On my way to the mechanic yesterday, the motor just up and quit. After towing to its destination, first thing we thought it was the fuel pump. So we ran a test via the pump prime plug on the fuel relay switch. Then the pump worked, so we thought it was the relay switch. Went out and got a new one and the same thing happened, no fuel getting to the carburetor. The only way we can get it to pump gas to the carburetor is by placing a hot wire in the pump prime plug, but the fuel stops right at the carburetor. No fuel makes it to the injectors and all this really only happens when you run a wire to the pump prime plug on the fuel relay switch. With the ignition nothing works: the fuel pump doesn't come on to even send anything to the carb. Is there a fuse that I'm missing? We have checked everything via placing a hot wire to it and it all stops at the tbi, even with hot wires. The motorhome fires right up the minute you pour a little bit of gas into the carburetor, but the minute you run out its a dead stick again.

    Hope this makes sense, I'm not sure what else to do we spent 6-7 hours troubleshooting and still nothing. If there are any questions, I will be checking quite often.

    Thanks again.

    1996 Fleetwood Southwind 454 TBI
     
  2. Guest

    Guest Guest

    RE: motorheads unite tbi help

    well one thing ,, i see u said TBI ,, i asume this is Throttle Body Injection ,, but u still say Carb ,, if it is TBI ,, it should have a fuel pressure test port on the line ,, i would hook a pressure gauge up there and see what u are really getting ,, and also ,, what chassis do u have ??? i would say chevy ,, since u said TBI ,, u also need to see if u are getting pulse to the injectors while cranking ,, u may have a bad cam sensor in the dist ,, (if u have one ) or a bad ground from the pcm ,, alot can be the cause on this . Also ,, the TBI system is known to have injector probs ,, they have a rebuild kit for it ,, but i thin IMO u really need to ck and see if u are getting pulse to the injectors ,, and ground also
    If u let us know what yr ,, and what model ,, we can help u out further :approve: :approve:
     
  3. hailo

    hailo New Member

    RE: motorheads unite tbi help

    ok after all that finally narrowed it doen to a fuse. the "ECM battery" we replaced it ran fine turned off the car to put the airfilter on. went to start it and it pops. put another one in and it pops even w/o the key in. so now i am at a loss. could this be the after math of the guy putting two 12 volt batteris in series instead of parralel. does the ecm go bad on these things?


    its a 1996 fleetwood southwind 454 tbi 34 foot wide body
     
  4. Guest

    Guest Guest

    RE: motorheads unite tbi help

    I don;t think the other batts are a prob ,, they would have blown fuses in the converter side ,, not the engine side ,, since u said "after the airfilter was installed" ,, i would ck an see if there isn't a wire pinched somewhere in the airfilter area ,, the coolant temp sensor and the map sensor wires are in that general area ,, ,, hope this helps :approve: :)
     

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