2002 explorer start problems

My 2002 Explorer Doesn't Start Somedays. I'm Not An Every Day Driver, And It May Sit For 5 Days Without Me Driving It. I TURN THE KEY AND IT SOUNDS LIKE ITS GOING TO START, THEN IT HAS THIS KNOCKING SOUND. When It Doesnt Start I Give It A Boost And It Starts Immediately. Also There Doesn't Seem To Be Any Other Electrical Problems (lights,radio, Etc. Seem Fine) So Could Anyone Guess What The Issue Is? It Has Only 40,000 Miles. THIS STATRED OUT AS A ONCE IN A BLUE PROBLEM, NOW IT ALMOST EVERY TIME I GO OUT TO DRIVE

That knocking noise is the lack of oil prior to the vehicle starting and the oil pump pumping oil up to the heads. You may want to start the engine up every 2-3 days just to circulate the oil, remember the recommended oil is 5-20 wt synthethic blend and it's light. Are you using synthetic blend or just using regular (petroleum based) oil? Also how often do you change oil? If you are the once in a while driver you need to change your oil sooner, look at owner manual and you will notice it says XX months or XXXX miles between the oil changes, the XX months will probably apply to you. I suggest that you start it up every couple of days and let it get warmed up or take it around the neighborhood for a spin. It's cheaper than a new engine or head replacement.

Hey XLT03, thanks for the advice. Sorry I didn't get back to you sooner, but I had some family issues I needed to take care of. Well here's what happened, I went to get an oil change (I was supposed to get one @ 38,000 miles, thats about 2000 miles ago!!) and the mechanic said I had multiple issues, one being the lack of oil. Besides that I had to get my engine flushed of "sludge", also he worked on my carburetor, changed my air filter, and gave me a gas treatment. Ever since she's been running just fine, with clean starts every time I go out. Just wanted to say THANKS again and if I could ever help out with something please don't hesitate to shoot me a line.


Thanks again,

Big Chuck 1548

Big Chuck 1548:

Change your oil every 3,500 miles if you can. I know the book says 5,000 miles. Your engine will last longer. Also the sludge issue will be minimized. You certainly want to check your oil level. When it's cold as it is now in Brooklyn, it take a bit longer for oil to get up to the top of the engine. You are WELCOME! That's what this forum is for, helping each other and sharing info.

Happy motoring.

my explorer sport trac after sitting over night when it is cold las in the 20 degrees it takes a minute or two for the oil pressure needle to go normal then the check gauge light turns off. should i be using a synthetic oil? my 2001 explorer has 68k miles , I already replaced the sprk plugs this helped the sluggish startupon cold mornings, i am only concerned about the oil pressure.

I believe that the 4.0 L engine use 5-30 wt - petroleum based, and the 4.6 uses 5-20wt synthethic blend. Make sure that you use the correct wt. oil I know that 5-20 may be a bit more difficult to find. The sport trac is 4.0L so use 5-30wt-petroleum based. How often are you changing your oil? 3,500 mile is a good interval. My thoughts, oil and filter is cheap, engine is not.

Are you having this problem in warm weather conditions or only in cold weather? If yes to both you may want to change the oil pressure switch.

It sounds to me that you have a CRANKING problem, instead of a starting problem. When the electrical power from the battery is marginal it may be able to crank the engine for a second or two, but it eventually weakens enough to where it can't crank any more and instead causes the starter relay make a heavy chattering noise. If, after you boost the battery to get the engine started, you hear a knocking noise then it could very well be a lubrication issue. I suggest you inspect the battery connections first , they may be covered in layer of corrosion that limits the amperage from getting to the starter. If that checks out, try a new battery. Hope this helps!