Truck backfired and now it won't start.

  • 1 POST
  • 5.7L
  • V8
  • 2WD
  • 320,000 MILES

Truck ran fine to the bus stop but seemed to have fouled a plug on the way home. It backfired and wouldn't start the next morning. One mechanic came and put it on a tester. He said the gear on the distributor needs to be replaced. Next mechanic said the gears don't strip so it's not the distributor. Third mechanic said it has jumped time. Please help. I don't even know which shop to tow it to. Thank you.

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Saturday, October 18th, 2014 AT 6:40 AM

1 Reply

  • 21,081 POSTS

With 320K miles on it, anything could be stripped. We can't tell you which one knows what they are talking about but there are tests that can be done to isolate the issue.

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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Saturday, October 18th, 2014 AT 11:20 AM

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