Hey there I’m hoping you could help me out. My wife’s car has some problems and the car is turning into a money pit. She drives a 2005 Nissan Sentra 1.8L with a little over 110,000 miles on it. The first issue started off with just a hard start on a cold start, you’d turn the key 2 or 3 times before it would start, and it would run just fine and that went on for a few months we thought nothing of it. Then the car started having a “misfire issue” (at least that’s what the scanner at autozone told me it was) where it would shake for a few seconds after the engine would start and then it would run like normal. I switched out the ignition coils and spark plugs hopping that would help the misfire go away but it didn’t help. It went away for a day and started up again. The hard start went away for a day or two after switching the coils and spark plugs but it came back with a vengeance. We took it to a local mechanic who suggested we switch out the fuel pump. We switched it out and it ran great for that afternoon but when my wife tried turning it on in the morning the engine just cranks but it doesn’t start. Do you have advice as to what to do next? There weren’t any codes to look at before the car stopped turning on.
Was the fuel filter changed along with the new pump?
No, i Believe the only thing replaced was the fuel pump.
You could have a clogged fuel filter. Most new fuel pumps require replacing the filter as well to keep the warranty in effect.
Thanks I’ll get one a new one for it. Do you think any sensors might need switching too? Like the cam or crank sensor?
It's possible but start with the simplest/cheapest things first. There is no doubt that a badly clogged fuel filter can stop an engine dead.
There weren’t any codes to look at before the car stopped turning on.
Do you mean to say even the gauge cluster lights won’t turn on?
See here for misfire diagnosis -
https://carkiller.com/scottykilmer/qa/misfire-4/
Do a load test on the battery and alternator.
My guess is a failing crankshaft position sensor or a faulty ECT sensor.
I'm not sold on a fuel delivery issue because the car wasn't exhibiting any problems while you were driving it under acceleration/load.
An intermittent No START could be caused by a failing fuel pump but you've replaced it and the problem persists.
But a failing crank sensor would have a hard time during cranking when battery voltage can fall to 10.5 volts or slightly below (the crank sensor operates on 12 volts and it's signal operates in the 0 volt to 9 volt range and if it's weak/failing it probably isn't going to be able to provide that voltage signal during cranking). So no coil triggering signal and no injector pulse because the computer needs the crankshaft position sensor signal to synchronize the cam sensor signal.
If the ECT sensor is lying (faulty) the air/fuel mixture won't be right for a cold (or hot) start.
Between the two, the crank sensor is more likely to fail without setting a code because during a cold start the computer compares the IAT and the ECT (temps) and expects to see them pretty close. If they aren't it will set a code)
Even though you have a new fuel pump you'll want to listen to make sure it kicks on for a second or two when you turn the key to ON.
If you can't hear it, remove the gas cap and listen there as your wife turns the key to ON.
If the fuel pump runs then the easiest thing to do (without getting your hands dirty) is to hook up a scanner and observe the ECT (temperature) and the RPMs (crankshaft position sensor) during cranking.
If the rpms remain at 0 during cranking then the crankshaft position sensor is likely the problem.
Your Sentra is 17 years old and it isn't getting any younger. If you plan to keep it get a scanner. It will come in handy in your Sentra's "declining years" because you can't afford to have mechanics replacing stuff like fuel pumps or yourself guessing and replacing ignition coils when those components aren't the problem. It gets too expensive.
Today and tomorrow Amazon has a Prime Deal on the CGSULIT SC301 scanner for $40. Even if you aren't a prime member, you can create a 30 day Prime "trial" membership, buy the scanner for $40 and then cancel the trial membership within 30 days and it won't cost you any money to get the deal. (I think it's regularly in the $55 to $65 price range if you don't feel like messing around with trial memberships on Amazon)
The cool part about this inexpensive scanner is that it can graph sensors like the Crank Sensor's RPM signal so if it's dropping out during cranking or running you can see it. It can probably graph the actual voltage signal too (even better).
