91 dodge dynasty no crank

help me understand, the car actually starts and runs for three seconds and then shuts off?

Itstart and will stay for a few seconds and then will stall. I replaced everythign I can think of could it be the computer?

it could be but I doubt it, have you changed the idle air control valve? have you tested fuel pressure?

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

yes tested the fuel pressure and it was low compared to what the book says it should be. COuld it be the fuel pump going out or the regulator. I can hear the pump come on when I turn key and then I hear it go off when it dies??????????? This one has me stumped?

it sounds like the pressure regulator,however, a dirty/clogged fuel filter will cause this too

the fuel filter was replaced also.

ok so we can cross that out

I dont really know what else to do can the computer be checked off the vehicle. We tried the thing to test the IAC valve and it is not moving in and out you can tell it is trying but just barely moves, we tried cleaning it but still no luck. Could it being bad cause the no crank issue? ALso we can smell gas when we try to crank it even though I dont touch the pedal??????Help out of many and out of patience!!!!!!!!!

BTW all this happened after replacing the starter and battery. I had it quit on me at store finally got it home and had starter tested and it was bad replaced it and battery. Drove to work that day and the next and then that afternoon went to leave work and would not crank has not cranked since. Had to have it towed home. Thought maybe a little background would help:)Thanks

*that was out of money and patience:)

I have replaced the pressure regulator with three different ones from a junkyard, not sure if they were any good though i know you cant tell by looking at them.

ok, I dont think the computer is the case at this point. we need to test spark and make sure that it getting both spark and fuel, and by what your saying the iac is no good, that will cause it not to continue to idle once its started

ok will try replacing it and will let you know. Thanks

very good

Well-replaced the IAC and still will not stay cranked. I dont know what else to do.

have they ever scanned for computer codes?

Yeah i have checked it by turning the key three times and get nothing but 12 and 55 which i know is battery has been undone and end of codes?

I have talked with a mechanic we know and he said somehting about checking pulse at the injectors what is that and what does that prove?Also when we checked the fuel pressure it jumped up to 48 and then quickly dropped down to 42 the pressure should be 48. Dont know if this means anything or not.

pulse at the injectors mean, that you have to hook up what is called noid lights, they are little led lights that plug into the harnass of each injector, as the computer engergizes the injector, the light will illuminate instead of the injector spraying fuel. what it proves is,that the ecm is energizing the injectors appropriately, the fuel pressure dropping from 48 to 42 is normal.

Took the car my mechanic and after month of sitting it decided to crank. Drive home noticed no oil pressure changed oil pressure switch and pressure went back up. Drove like three miles down the road next day and oil pressure just dropped to zero and car quit would not crank sounded like locked up motor. Had towed home and next day pressure was back up and cranked up. Whining noise coming from drivers side of motor. Not really sure what would cause pressure to drop and go back up like that. Any help is appreciated.

Does anyone have any idea what my problem might be??????????