Engine Mechanical problem
1997 Saturn SC2 4 cyl Two Wheel Drive Manual 160000 miles
car died one morning after short drive, would not turn back on. Two hours later started fine, no problems for a month. Other day, didn't start again. This time for good. Have checked other forums. Replaced spark plugs, coolant temperature sensor, crankshaft position sensor, and also pretty sure it's not ignition coils. Tried push starting to see if it was starter. No luck. At a loss.
car would initially crank over but not get final turn. All electrical working fine, even though been workin on it so long, I need to charge battery after every test
If you need to charge the battery after every test, then you need to replace the battery before going any further. Once you have done that, you can start to perform the necessary tests.
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.
August, 27, 2010 AT 12:05 PM
First of all thank you so much for your donation. The easiest way to check for spark on your engine is two take off two spark plug wire's off the coil's that are right next to each other have some one crank it over and see if the spark jump's from tower to tower. Then put those back on then pull the other two off that are right next to each other and do the same thing. That way you test both coil's if you have spark then I would move onto checking the fuel pressure. That's easy to check you can rent a fuel pressure gauge from auto zone they have them they even have a kit that come's with a multimeter too. If you follow the line going to the fuel rail there is a cap on the line take that cap off that's where you screw the fuel pressure gauge on screw it on then crank the engine for 5 second's then read the pressure it should also hold steady. Also see if you can rent a noid light that plug's in to your injector plug instead of your injector. You would unplug each injector and plug the noid light into each plug then crank the engine and watch for the flashing light. See if you can rent a scanner to read code's also see if you can get one that read's live engine data. Let me know what you find.