Engine will not start

Tiny
JILL MAHALETZ
  • MEMBER
  • 1 POST
  • 2007 JEEP GRAND CHEROKEE
  • 3.7L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 169,576 MILES
Check engine light on did read evap codes and dash error read “ Check gas cap”. Replaced gas cap and reset computer, check engine a gas cap warnings kept coming back. Had leaky radiator, replaced. Gas cap warning stopped coming on fit check engine light still on. Replaced charcoal canister valve box in rear “looked damaged, corner was split”. Reset again, check engine light back on. Vehicle did run, kind of seem to bog some at acceleration and almost stalling idle at intersections. Now all it does is crank but no start. Reads only code P0004. Says replace fuel pump. I’ve heard that replacing fuel pump may not be the problem. What else should I check before replacing pump? Or is that what it definitely is?
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Sunday, August 30th, 2020 AT 10:26 AM (Merged)
Tiny
SCGRANTURISMO
  • MECHANIC
  • 4,897 POSTS
Hello,

Could you please double check the Direct Trouble Code[DTC] number for us again? The list of "P" codes for your vehicle starts at P0013A and goes up from there. There is no listing for DTC P0004. Please get back to us with what you find out and we can go from there.

Thanks,
Alex
2CarPros
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Sunday, August 30th, 2020 AT 10:26 AM (Merged)
Tiny
DONNA0728
  • MEMBER
  • 7 POSTS
  • 2007 JEEP GRAND CHEROKEE
  • 88,000 MILES
My 2007 JGC wont start. Just got it back from the garage for hesitation and bucking, they replaced the front control module, now it doesnt want to start. Any ideas?
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Sunday, August 30th, 2020 AT 10:27 AM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
  • 20,757 POSTS
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 30th, 2020 AT 10:27 AM (Merged)

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