4 Wheel Drive/SUVs: 1991 Jeep Cherokee Sport, No Start, jeep cherokee sport, throttle position sensor

Question
I had a problem about 3 weeks ago when my jeep would not start. The battery seemed fine and the started attempted to crank, the battery light is on as well the lights are strong.  I had it towed to a local garage.  They said it was flooded and that I had the wrong plugs (they were too good).  About $200 later I have the same problem.  Now some others are indicating a "crank shaft position sensor" or a combination of a 2 pin balast and a relay switch from the battery.  I can I get to the bottom of the problem without signing a blank cheque.  Also, where is the crank shaft position sensor and how do you replace it, as a do-it-yourselfer.  Thanks in advance for your help

Answer
Frank,

I would suggest that you start by buying a repair manual.  You can purchase a manufacturer's shop manual for the Jeep, but they are quite expensive, normally costing, around $100.  A Chilton's or a Hayne's manual can be purchased at most auto parts stores for $20, and they have a lot of information on basic trouble shooting, and repairs.  These manuals are designed for a year or range of years for specific vehicles, and are invaluable if you are planning on doing any repairs yourself.

I would suspect that the diagnosis is wrong.  There are several sensors that can cause this.  If it is, in fact flooding, there is a unit, called the throttle position sensor that can cause this.

Without actually looking at the vehicle, I would hesitate to confirm any diagnosis.  If it starts ok, and runs with new plugs for a short time, you may have a plugged fuel filter.  Try replacing this first, as it is a fairly inexpensive check.  If it hasn't been changed, then it's way over due.

If you can't figure out the problem using the manual, and checking it out yourself, see if you can find a reputable shop to run a diagnostic test on the Jeep.  I would find a local 4x4 club, and see if they can suggest a good shop.

Carl