Engine won't fire

Tiny
JCH
  • MEMBER
  • 1990 DODGE RAM
  • V8
  • 2WD
  • AUTOMATIC
  • 100,000 MILES
My truck wont start it was running fine with no problems I went out to start it and all it did was crank over but never did fire. I checked for spark at the distributor by pulling the coil wire and cranking the engine over and got no spark. I replaced the coil with a new one but still no spark. Its not even trying to fire I poured gas direct in the carb still no start it has to be electrical but where do I go from here its hard to believe something just quit with no sign of going bad it has never not started for me. I am a car guy from way back but dont do well with trying to find electrical problems can you give me some direction of where to look and what to replace.
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Sunday, October 26th, 2008 AT 6:58 PM

21 Replies

Tiny
RASMATAZ
  • MEMBER
Hello,

This sounds like the crankshaft position sensor (hall effect) when out they do out all the time in these trucks but to be sure run down this guide and check out the diagrams below.

https://www.2carpros.com/articles/car-cranks-but-wont-start

Check out the diagrams (Below). Please let us know what you find. We are interested to see what it is.
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Sunday, October 26th, 2008 AT 10:10 PM
Tiny
OIDAVEY
  • MEMBER
Thank you for this post I got a new distributor from Rockauto cost me $76.00 runs like a champ! I love this site.
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Thursday, November 1st, 2018 AT 6:17 PM
Tiny
LAVAHALO
  • MEMBER
  • 1990 DODGE RAM
  • AUTOMATIC
  • 100,000 MILES
I have a Dodge Ram 250 with a 3.9 liter engine. It sounds like it wants to crank but will not start. Have replaced coil, brain, distrubor, alternator, battery. Told to change crcnk sensor, but can not find one. Please help?
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Thursday, November 1st, 2018 AT 6:18 PM (Merged)
Tiny
LAVAHALO
  • MEMBER
*crank sensor
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Thursday, November 1st, 2018 AT 6:18 PM (Merged)
Tiny
WRENCHTECH
  • EXPERT
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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Thursday, November 1st, 2018 AT 6:18 PM (Merged)
Tiny
LAVAHALO
  • MEMBER
There was no spark at the end of the plug wire. There was also nopower supply to the plus side of the coil? Next?
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Thursday, November 1st, 2018 AT 6:18 PM (Merged)
Tiny
WRENCHTECH
  • EXPERT
The rest of the tests.
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Thursday, November 1st, 2018 AT 6:18 PM (Merged)
Tiny
MPMPMP41619
  • MEMBER
  • 1990 DODGE RAM
  • V8
  • 2WD
  • AUTOMATIC
  • 100,000,000 MILES
What could be the problem with my 1990 dodge ram 250 if it wont start and its not the battery or the alternator? In the past someone put jumper cables in wrong to could that be the problem?
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Thursday, November 1st, 2018 AT 6:18 PM (Merged)
Tiny
CARADIODOC
  • EXPERT
How do you know it's not the alternator if the engine doesn't run? What are the symptoms?
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Thursday, November 1st, 2018 AT 6:18 PM (Merged)
Tiny
LAVAHALO
  • MEMBER
Did not do them as I thought if the first one failed, there would be an answer, plus I am not sure he can. Was told to replace the crank sensor, but could not find one. Is there one?
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Thursday, November 1st, 2018 AT 6:18 PM (Merged)
Tiny
RASMATAZ
  • MEMBER
Jumping it the wrong way could blow a fusible link/s
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Thursday, November 1st, 2018 AT 6:18 PM (Merged)
Tiny
WRENCHTECH
  • EXPERT
Yes, you do need to complete the rest of the testing for me to give you any kind of conclusion as to what might be the problem. Many functions share common components.
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Thursday, November 1st, 2018 AT 6:18 PM (Merged)
Tiny
LAVAHALO
  • MEMBER
Is there a crank sensor on this engine? If so where?
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Thursday, November 1st, 2018 AT 6:18 PM (Merged)
Tiny
WRENCHTECH
  • EXPERT
No, it doesn't
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Thursday, November 1st, 2018 AT 6:18 PM (Merged)
Tiny
LAVAHALO
  • MEMBER
It does not have injectors, it has spark plugs.
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Thursday, November 1st, 2018 AT 6:18 PM (Merged)
Tiny
CLEZZY
  • MEMBER
  • 1990 DODGE RAM
Whats up Guys. I have this truck that won't start. I don't have and fuel pressure, or spark. I checked for voltage at the coil- none. Checked for voltage at the coil pick up and only had 2volts. I was using my vantage to check for voltage and it said i'm suppose to have 8volts. Also I see there is a ASD relay(auto shut down). I jumped the terminals and heard the fuel pump come on.I found a diagram on line(I don't know how reliable it is)and I see there is a fuseible link in the diagram. Could you tell me where that might be, And any other things I need to check
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Thursday, November 1st, 2018 AT 6:18 PM (Merged)
Tiny
ASEMASTER6371
  • EXPERT
Fusible links are off the positive cable of the battery by the fuse box.

The asd relay has 2 powers, one key on and one battery. The 3rd terminal is the load and the other is the pcm grounding the relay. Verify the powers first.

Roy
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Thursday, November 1st, 2018 AT 6:18 PM (Merged)
Tiny
SOUTHERNBOUND
  • MEMBER
  • 1985 DODGE RAM
  • 6 CYL
  • 2WD
  • MANUAL
  • 54,386 MILES
I have a 85 dodge d150 with a 225 slant six. I installed a new ignition switch, and starter relay switch. Since the new ignition was installed my truck will not start with the key. All dash lights are on while key is in run position. When it is turned to start position nothing happens. I can leave the key in run position then connect the starter post and it will start and run. All lights and radio work. When I turn the key to off position it turns off the engine. Anyone know what could be causing this?
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Thursday, November 1st, 2018 AT 6:19 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • EXPERT
IT sounds like the lever isn't moving the ignition switch far enough. Have you checked it?
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Thursday, November 1st, 2018 AT 6:19 PM (Merged)
Tiny
SOUTHERNBOUND
  • MEMBER
Yes I have checked it. I also unbolted the switch from inside the column and turned it to the start position by hand. Still nothing happens. I checked the neutral safety as well, used a jumper to bypass and it still didn't crank over. I have read all related material in a chilton's manual and have not found an answer to the problem.
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Thursday, November 1st, 2018 AT 6:19 PM (Merged)

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