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Identical cold start everyday

Discussion in 'Stock 1995 - 2001 Explorers' started by Adams95, June 18, 2011.

^^Searches ExplorerForum.com^^
  1. Adams95

    Adams95 New Member

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    So everyday when I hop in my '95 4.0 ohv explorer w/ 215k miles this is exactly what happens:
    I turn the key to on, wait a sec sometimes even 2-4 seconds, then crank the motor for around 2 seconds. The engine doesn't turn over. I pause, crank the motor and it starts rough...almost like its too rich, however it recovers and runs solid the rest of the drive (besides poor mpg). It idles at a rock solid 900rpm with or without a/c.

    The engine has new plugs, new wires, new t-stat, clean MAF, clean air temp sensor, and a new IAC.
    One thing I plan on changing is the O2 sensors, they are the stock O2 sensors. The only thing thats making me 2nd guess the changing of the O2 sensors is that I've ran a KOEO and a KOER test the past 2 days. Both times the tests just come back with '111'.
    What do you think is causing the motor to not start cleanly? Thanks for the help as always guys.
     
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  3. Adams95

    Adams95 New Member

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    any ideas guys? anyone who's had similiar problems?
     
  4. 2000StreetRod

    2000StreetRod Staff Member Moderator Elite Explorer

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    ECT sensor?

    When you say "The engine doesn't turn over" I assume you mean the engine cranks but doesn't start. You may want to test the engine coolant temperature (ECT) sensor. The PCM may think the engine is warm when it is actually cold. Does the engine start and run normally after it is warmed up?

    The O2 sensors have to be warm to function properly. That's why they have heaters to reduce the warmup time. The PCM runs in open loop (ignores the O2 sensors) at engine start. However, the long term fuel trims at shut down are retained in nonvolatile memory for the next engine start. Does black smoke emit from the tailpipe? Do you have carbon buildup on the spark plug electrodes/insulators? Those are indications of an excessively rich mixture.
     
  5. Adams95

    Adams95 New Member

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    Thanks for the reply 2000, I'll pull a spark plug tonight and see what kind of shape they're currently in (they were put in only 2 months ago).

    Once the truck starts and runs for about 10 seconds it runs well, but it never fully gets "warmed up." If its 105 degrees outside and the truck sits with a/c on max at idle for 20 minutes it will get almost to the little logo for coolant temp, but as soon as i start driving it drops down to about 1/3 on the gauge. Even if I drive to work in 90 degree weather (20 min drive), the temp gauge never even gets to a 1/3 of the way up.
    In another post that I have...talking about my poor MPG...I cleaned my Throttle Body last night when I took it off to replace the ECT.
    However what I found on the backside of the TB and inside the intake manifold is scary! The previous owner drove the truck for about 150,000 miles with the thermostat stuck open.

    Here's the post with pictures: http://www.explorerforum.com/forums/showthread.php?t=319574&page=2

    I replaced the ECT and cleaned the TB last night, but now the truck is acting a little funny. Instead of idling like a rock at 900 RPM. It idles around 1000 and wanders just a little, about 100 rpm up or down. Also, I'm not sure if this is normal, but as soon as i turn the a/c on the idle jumps up to 1200 and then slowly gets back down to 1000, where then it continues to slightly hunt 100 rpm in either direction.

    Do you think I may have got some gunk from the TB loose and then was sucked up by the new IAC I just put in 2 nights ago?
     
  6. 2000StreetRod

    2000StreetRod Staff Member Moderator Elite Explorer

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    clarification

    The thermostat controls the engine temperature and affects engine operation.
    The coolant temperature sender drives the temperature gauge in the instrument cluster and has no affect on the engine.
    The engine coolant temperature (ECT) sensor reports the coolant temperature to the PCM and significantly affects the air/fuel ratio of the engine.

    From your other thread I suspect that you replaced the coolant temperature sender since your gauge was always reading low temperature on a hot day after replacing the thermostat. As bobflood stated in the other thread "Did you ever check out the Engine Coolant Temp sensor that the ECU uses??"
     
  7. Adams95

    Adams95 New Member

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    No, I believe my gauge is fine, last night I replaced the ECT that the ECU uses. No change in the way the truck runs or it's operating temperature issue and it's actually running just a little bit rougher, but that could be because of the TB cleaning.
     
  8. 2000StreetRod

    2000StreetRod Staff Member Moderator Elite Explorer

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    throttle body port?

    Make sure the small port near the throttle plate is not clogged with carbon and that the hose that connects to the port pipe has no splits and is on tight.
     
  9. Adams95

    Adams95 New Member

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    Thanks, I'm going to pull the TB out tonight and really clean it. As well as clean the IAC to make sure nothing plugged it up.
    I noticed that the port pipe's vacuum hose is very tight, is that normal?
     
  10. Adams95

    Adams95 New Member

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    Thanks, I'm going to pull the TB out tonight and really clean it. As well as clean the IAC to make sure nothing plugged it up.
    I noticed that the port pipe's vacuum hose is very tight, is that normal?
     
  11. Macgiobuin

    Macgiobuin Active Member

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    IAC valve possibile

    Sounds like an Idle Air Control valve problem to me. Take it out, play with it to see if it sticks in either the open or closed position. Use Gumout or WD40 to clean out the whole mechanism. Then give it a go. Good luck.
     
  12. Adams95

    Adams95 New Member

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    I actually just replaced the IAC 3 days ago. I even took out the IAC today once i got home from work and cleaned it out (it still looked spotless, but i cleaned it anyway). I ran a KOEO/KOER test and KOEO came back with 111 while KOER came back with a 411 code.

    I also disconnected the IAC while the car was running and the idle dropped to 500 rpm or so. Thats how the IAC is supposed to perform correct?
     
  13. 4pullingGM

    4pullingGM Active Member

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    Yep, the idle should drop or the engine stalls when the iac is disconnected. Maybe a fuel injector or fuel pressure regulator are bleeding down? That would cause a hard start and make it run rough till it clears out the extra fuel.
     
  14. Adams95

    Adams95 New Member

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    Hmm, that's a good thought, but how would I go about testing and/or fixing this?
     
  15. Adams95

    Adams95 New Member

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    I just thought of something, should the ECT have a bit of its thread sticking out? I tightened pretty hard and I wonder if it's possible to bottom out on the water pump?
     
  16. budwich

    budwich Well-Known Member

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    on the "leaky fuel system", you can get an idea of that with a fuel pressure gauge. Hook it up, run the truck til it is "happy" (ie. running smooth and such). Check the pressure. Turn the truck off, and monitor the pressure thereafter for a "trickle down" of pressure. There are discussions on that, can't remember the details, but the pressure should hold (in some form) for a fairly long period. Doesn't necessarily tell you if its a injector or regulator but may give you an idea of "next steps".
     
  17. matt0248

    matt0248 Active Member

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    From your description is does sound like you have a leaking fuel pressure regulator or leaking fuel injectors. The pressure regulator is easy to check once it is located. Pull the vacuum hose off the end and check for fuel, there should be no fuel in the vacuum hose. If there is fuel in the hose the regulators diaphram is leaking. This almost always results in a hard start after the vehicle has been sitting for awhile, but once it is running the PCM can try to compensate for the extra fuel that is being sucked into the intake.
     
  18. Adams95

    Adams95 New Member

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    I've got an interesting update, I noticed today that if i leave the key to on for about 10-15 seconds the truck starts up first time i try...wouldn't this mean that its not actually too rich starting, but actually not getting enough fuel pressure?
    My other question is...on a '95 OHV where is the FPR? Is it in the fuel tank? and if so where is the vacuum line for it so i can test for gas in the line. Thanks guys
     
  19. 2000StreetRod

    2000StreetRod Staff Member Moderator Elite Explorer

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    FPR & fuel filter

    The fuel pressure regulator is on the fuel rail. Has it been more than 30,000 miles since you replaced the fuel filter?
     
  20. budwich

    budwich Well-Known Member

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    Well, I am not sure whether 10-15 seconds or 10 minutes even matters.... cause basically, the system is "designed" to turn OFF the pump after 2-3 seconds. Your key to your "guess work" is a fuel pressure test.
     
  21. 4pullingGM

    4pullingGM Active Member

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    Pretty sure the fuel pressure regulator is on the passenger side of the engine. A fuel pressure gauge, as others have stated, will be a big help.
     






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