tested the crank sensor a second time and it failed so im gonna replace the crank sensor and see if my problem goes away it was able to start today so i unplugged the crank sensor and tested it and it passed so its off and on ill update in the next day or so after i replace the crank sensor

 

it wasnt the crank sensor i started the truck after i replaced it and it ran then i shut it off and it wouldnt start again so the truck will warm up so im thinkin somethins gettin hot real fast and tellin the engine to shut off

 

I have a couple suggestions, first one would be, to add a couple comma's and period's to your your post's . So we don't have a headache after reading them.


Second, get a fuel pressure tester and see what it reads after warm up.

Third, get a blow dryer and aim it towards the PCM to get it good and hot before you start the motor and see what happens.

And finally, please add ALL the info about your truck to your sig and your profile. Thank You, and have a nice day.

 

i tried to find my sig but couldnt i would appreciate it if you told me how.

the truck is runnin now, but when i shut the door or hood it shuts the engine off, i think a wire is grounding out on something but im not sure, i also have a gas leak coming from the top of the gas tank that i didnt notice till now, oh and im hearing something knocking around whenever i get around 2 grand

 

On the bar across the close-to-top, click on User CP, on the left, click on Edit Sig. Fill it out.

So, open the hood, start the engine, and start tapping on things. See where you tap that causes the truck to quit. Start with the PCM.

 

Yea, and use a sledgehammer to tap the PCM. It works the best for tapping.

 

You say the truck doesnt start but does it at least turn over when you try to start it?

See if this helps...

What you will need is at least Five feet of 5/16" Fuel line, One clean 5 Gallon Bucket,a pair of latex or rubber gloves for handing fuel, a handful of shop rags, and some big pieces of cardboard to prevent making a mess.

First, disconnect your battery!
If you want to see if the fuel pump is primed and working, lay the cardboard under the area under your truck between the frame and your transmission. Put on your gloves, grab your bucket and rags, and crawl under your truck onto the cardboard. While under the truck look towards the driver side of the frame between the frame and transmission linkages. On the inside of the frame rail there is a fuel line sitting just across the way from your transmission. Using your gloves with rags and bucket handy on top of the cardboard you can unclip the fuel line from the gas tank to the engine. Disconnect that fuel line and let the fuel leak into your bucket. After the two parts of the line are separated. Use the 5/16" fuel line to place over the section of fuel line coming from the gas tank with the other end in the 5 gallon bucket. Reconnect your battery and turn the key to the on position just before that start position which would energize the starter. Watch to see the amount of fuel flowing through the line into the bucket.

If there seems to be sufficient fuel flow, reconnect the fuel lines on the truck.

Check the exhaust system to see if its clogged. Undo the Four Bolts holding your exhaust manifolds to your exhaust pipes. 9/16" socket if everything is still stock. After undoing the bolts, pull on the exhaust pipes below the exhaust manifolds to separate the engine from the exhaust system and with a gap now separating the exhaust system from the engine try starting the truck.

Those are a couple of tests to help diagnose the problem without spending much in the process.

Try the exhaust thing first for simplicity sake since you can do that with nothing more then a socket set. If the exhaust thing does the trick, your catalytic conver is toast and your muffler may be plugged. Costs about 100 for a new muffler and 250 for the catalytic converter. Shop around if you want to save some cash but that is a ballpark estimate.

 

The fuel pump doesn't come on when it wont start and I know its not bad because I bypassed the auto shutdown relay and the fuel pump relay and the truck starts and when I put the relays back in it starts

Could low fuel pressure cause it not to run?

Its not the exhaust I know the symptoms of that, my last Dodge went through that before I sold it and it got to a point where the truck wouldn't even start, I thought that to but my exhaust comes out the tailpipe fine
:

 

Without checking the fuel pressure with a gauge you'll never know. And I'd remove the precat o2 and see what happens. I've worked on enough jeeps and Rams that seemed like the exhaust was coming out fine only to have them start and run fine after removing the o2.

 

Ive had the o2 unplugged and havent plugged it back in since friday, i drove it friday night all saturday and half of sunday till it died again, the truck started today and i pulled codes again and got a code 53 which came up as DRB displays pcm failure spi communication. condition is: pcm detects serial peripheral interface communications failure