96 460 Hard Start when warm

Discussion in 'General Automotive Questions' started by ForistellFord, Mar 17, 2017.

  1. I'll ask here, even though I'll get some wiseacre replies.

    My 96 460 has been hard to start when it's warmed up. I go to start it and it's fine. I come out of the store or wherever, and it cranks for a while with no fire. Or, it will fire, struggle, then die. After a few more minutes it fires up and stays running. Any thoughts?
     
  2. It's OBD-I, and I have not checked for any code.
     
  3. ribald1

    ribald1 In Maximum Overdrive PLATINUM MEMBER

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    Check the manifold fuel pressure regulator. It may be sticking in the low pressure position.
     
  4. Not intending this to be a dumb question, but does it have one? It's an E-350, and was a year or two behind the upgrades the 96 MY got for the 150 series. Still has the MAF; I believe the eliminated that for the 150's in 96+... I was wondering if it could be the MAF sensor or even fuel filter?
     
  5. burninbush

    burninbush In Maximum Overdrive

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    "Why doesn't my car start" ...

    Go get the readout from the computer, might save you a bunch of useless work. I'm surprised to hear of a '96 that doesn't have an OBD-II computer. On my car you can read-out any codes from switching it on/off 3 times without cranking, the numbers appear in the mileage indicator. Ford might do the same --
     
  6. ribald1

    ribald1 In Maximum Overdrive PLATINUM MEMBER

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    Look on the exit end of the fuel rail. If you have one it will sit between the fuel rail and the fuel return line and have either a vacuum line or a wire going to it.
    You can test it with a fuel pressure tester. If the pressure is around 30 PSI while cranking it is sticking open.
    Of course, a weak fuel pump will yield the same.
    These exist on most emission controlled EFI systems to reduce fuel pressure during cruise to give the computer more control over the fuel delivery.
     
  7. Don't be a smarty mouth BB. Ford switched to OBD-II in 1996 but did not do so for the 250 and up series.
     
  8. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    Trucks weren't all built with OBD II back in '96; they had exemption from the EPA to give them the ability to build in OBD II in the major truck segment first--the half-ton rigs. And SEFI is on engines of that era, irrespective of which OBD they were built under.

    To answer your question, there are a few things that are affected by heat soaking. The fuel pump is one, the ignition coil, Hall Effect pickup in the dizzy and the TFI module are three more, the computer system (sensors, computer and power relays) is the rest. so start at the basics: pull the doghouse and have a spark tester on the #8 wire/plug, a fuel pressure gauge on the test port and if you can find one to use, a scan tool with live data so you can check for CKP/CMP operation, MAF measurement, ECT/ACT temperature measurements. Drive the van to get it hot, then when you get back to where you're going to do the work, start looking at the pressure gauge, spark tester and scantool, see if anything is outside of normal readings. That's how and where you start on an SEFI engine--spark then fuel (fuel pressure, then injector control).
     
  9. So I decided to shotgun it. I got a timing chain kit, a water pump, exhaust manifold gaskets and bolts, front and rear brakes, plugs, wires, rotor and cap, shocks, a battery, thermostat, hoses, fuel filter, and a transmission filter kit. That ought to do it.
     
  10. That's all for routine PM anyway, not a shotgun attempt at fixing anything. Bubba needs some lovin' anyway.

    So, is there a decent bolt-on TB I can slap on this puppy to wake it up a little?
     
  11. ribald1

    ribald1 In Maximum Overdrive PLATINUM MEMBER

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    A bigger TB won't change anything until you really rev it up.
    Quality injectors and a new O2 sensors, then get the computer to bring in a bit more timing by either chipping it or altering the timing point.
     
  12. burninbush

    burninbush In Maximum Overdrive

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    Somebody wrote on here up the thread; take it to some place that can read-out your computer. Why just change stuff at random? You may have a specific problem ID'ed if you get the readout. Checking the advice you've already been given, it's doubtful it would run with a bad O2 sensor, and bad injectors would not make it hard to start unless they all went bad at once; reading the computer would tell you about failing injectors. The computer will keep track of previous failures.

    See if you can get a fuel pump pressure readout on it. Ideally do that when it won't start, could be a failing relay to turn on the pump. If you turn it on (but not crank) can you hear the fuel pump timeout? Should run for a couple seconds and then turn off.

    It will surely have camshaft sensor and crankshaft sensors -- those will fail and then begin working again.
     
    HuevosRanchero likes this.
  13. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    It's also known in Ford truck circles that the 460 exhaust on those EFI engines are way restricted, causing the exhaust manifold gaskets to blow out. Take your rig to an exhaust shop, have them do a backpressure test. Factory spec is 1/2 to 3/4 lb. of BP, and anything over 1 can cause problems. Have them test in front of and behind the cat, because both the cat and the muffler can restrict it.
     
  14. Oh, you guys. So sensitive. I didn't get those parts as a solution to the problem. I got them because he's 21 and needs some fixups. I'm not worried about any sort of huge potential because it starts hard sometimes. I just like to hear you guys talk. Yeah, the problem is happening. But it's a 21 year old vehicle and the world won't stop if it falls apart.
     
  15. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    And BB has a good point. I started getting bad misfires on the Exploder, and I know it needs top end work (intake coolant seep is the big reason), but I had it diagnosed to find out the #4 and 6 injectors are on their way out, and that the bank 1 cat is likely melting down.
     
  16. Getting it apart. Any tips and tricks for getting off the water pump and timing cover that may help? Not having issues, just looking for experienced voices.

    [​IMG]
     
  17. It doesn't hard start when warm anymore. Guess one of those things fixed it.
     
  18. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    Woo Hoo! We like that....
     
    ForistellFord likes this.
  19. Probably the cap and rotor. Them boys was ate up royal.
     

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