Engine cranks but does not start

Tiny
PAUL MARION
  • MEMBER
  • 1983 JEEP WAGONEER
  • 5.9L
  • V8
  • 4WD
  • AUTOMATIC
  • 202,690 MILES
Replaced ecm, carb rebuilt, new wires, new coil, rotor and cap new. New remote starter, and new fuel pump. Plus new air and fuel filters. Some new hoses for various plugs and connections, plus egr new.
Ran great for about a week, then it would crank but not start. Got spark and fuel. Battery charged and used jump starter when cranking.
Saturday, August 15th, 2015 AT 8:11 AM

5 Replies

Tiny
WRENCHTECH
  • MECHANIC
  • 20,758 POSTS
Are the plugs getting dark fouled or staying white?
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Saturday, August 15th, 2015 AT 8:28 AM
Tiny
PAUL MARION
  • MEMBER
  • 3 POSTS
Pulled #3 plug. It was dark from before. Was not wet or fouled.
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Saturday, August 15th, 2015 AT 9:23 AM
Tiny
WRENCHTECH
  • MECHANIC
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You replaced cap, rotor and wires. Why not plugs, especially if they were previously fouled?
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Saturday, August 15th, 2015 AT 10:11 AM
Tiny
PAUL MARION
  • MEMBER
  • 3 POSTS
Like I said, the plug was not fouled. Why change plugs when this is apparently an electrical problem? Have spark to coil but not to plugs, why?
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Sunday, August 16th, 2015 AT 9:47 AM
Tiny
WRENCHTECH
  • MECHANIC
  • 20,758 POSTS
No you don't. The coil is the part that creates the spark so you don't have spark going to it.

Follow this

All "crank, no start" conditions are approached in the same way. Every engine requires certain functions to be able to run. Some of these functions rely on specific components to work and some components are part of more than one function so it is important to see the whole picture to be able to conclude anything about what may have failed. Also, these functions can ONLY be tested during the failure. Any other time and they will simply test good because the problem isn't present at the moment.
If you approach this in any other way, you are merely guessing and that only serves to replace unnecessary parts and wastes money.

Every engine requires spark, fuel and compression to run. That's what we have to look for.

These are the basics that need to be tested and will give us the info required to isolate a cause.

1) Test for spark at the plug end of the wire using a spark tester. If none found, check for power supply on the + terminal of the coil with the key on.

2) Test for injector pulse using a small bulb called a noid light. If none found, check for power supply at one side of the injector with the key on.

3) Use a fuel pressure gauge to test for correct fuel pressure, also noticing if the pressure holds when key is shut off.

4) If all of these things check good, then you would need to do a complete compression test.

Once you have determined which of these functions has dropped out,
you will know which system is having the problem.
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Sunday, August 16th, 2015 AT 10:52 AM

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