Cadillac Repair: 1995 cadillac wont start, fuel filter replacement, autoparts store

Question
after I posted my question I read some of the past ones and seen you ask for codes so I ran thur the code and shut the key off and then tried to start it and it started could have running the codes have reset something i ran the car today and it stalled again but started right up could I have air in the line from changing the filter help
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Followup To

Question -
1995 cadillac concourse 4.6 northstar
while driving home from vacation I stoped and got gas about 50 mile down the road the car just shut off, I pulled off the road put the car in park and it started right up. went about 10-15 miles the same thing another 10-15 mile the same thing when I got back on the road it seemed to running rough so i jumped on the gas a few times and it ran fine for the rest of the trip about 200 miles, next day ran a few short trips then went about 45 mile got gas and the same thing happened 3rd time it would not start. next day it started ran a little bit shut it off and now it won't start. opened the gas cap and turned the key on I can here the fuel pump running. and now I just replaced the fuel filter still won't start.I need my car for work it is the only one I got please help a.s.a.p.

Answer -
Hi nibjna,

    With a problem like yours it would help to know what the fuel pressure is. Because it starts and dies it could be a fuel pump problem where its not putting out enough pressure. There is a fuel pressure schrader valve under the top engine cover that takes a screw-on gauge that can sometimes be gotten from the autoparts store as a loaner tool. It should be 41-47psi with the key on engine not running. Also you would need to check for spark. Since it doesn't start now hopefully it will be easy to diagnose. However if it does turn out to be low fuel pressure the pump is in the tank and it will need to come down. Bill

Answer
Hi nibjna,

     After the engine has been started after a fuel filter replacement that is all it takes to get the air out of the lines. However if you have a bad checkvalve in the fuel pump it will allow the fuel pressure to drain out in a matter of 5 minuits and then when you go to start the engine again  the fuel lines need to refill and you will get a longer crank time before the engine starts. I still feel that hooking up a fuel pressure gauge is the way to go and then you will know if the fuel pump is a problem or if you need to look elsewhere.

     As far as resetting the computor because you cleared the codes its not likely that that happened. To reset the computor takes disconnecting the battery or unplugging the computor for up to 10 minuits and then it will reset itself.

     If you lost spark there are several things that can when they heat up cause the engine not to start. Those being the crankshaft sensors, ignition module for the sparkplug coils, camshaft sensor and computor. I wouldn't suggest replaceing any of them but to test for spark to determine if one of them might be bad and then test to see which one is the problem.

      One other thought that came to mind is that sometimes where the negative battery cable attaches to the engine near the LH side front of the engine by the serpentine belt can loosen up and cause the engine not to start. It might be worth a look.  Bill