Engine won't fire

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.

Thank you for this post I got a new distributor from Rockauto cost me $76.00 runs like a champ! I love this site.

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?

*crank sensor

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.

There was no spark at the end of the plug wire. There was also nopower supply to the plus side of the coil? next?

The rest of the tests.

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?

How do you know it's not the alternator if the engine doesn't run? What are the symptoms?

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?

Jumping it the wrong way could blow a fusible link/s

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.

is there a crank sensor on this engine? If so where?

No, it doesn't

It does not have injectors, it has spark plugs.

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

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

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?

IT sounds like the lever isn't moving the ignition switch far enough. Have you checked it?

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.

Have you checked the starter relay? Is it getting power?