Tip & How-To about Chevrolet 1500

Engine will not start

Either you are not getting spark or not getting fuel. A bad crankshaft position sensor would cause no spark at all. You can pull one spark plug, place it back on the plug wire. Lay the plug electrode next to a metal surface. Have someone else crank over the engine while you observe for spark. You should see a spark jump from plug to the metal surface. (plug electrode should be no more than 1/4" away) If you don't have spark, put the plug back in and move on to the next plug and try that one. (the correct way is to use a spark tester) If you have no spark in any plug, you may want to test the crankshaft position sensor with an ohmmeter. You can also use a meter to test power at the ignition module.
If you find that you do have spark in every plug, then it's possible that you don't have fuel. There is a fuel pressure test port on the fuel rail. There is a cap and a valve. With the key in ON position ,you can place rag over the test port, press in on the valve and there should be fuel that comes out meaning there is fuel pressure. (the correct way is to use a fuel pressure gauge if you have one)
If you find there is no fuel pressure, turn the key off and back on again. You should hear the fuel pump. If you can hear the fuel pump, then it is working. That means you may have a plugged fuel filter or faulty fuel pressure regulator. If you do not have hear the fuel pump, check the fuse and fuel pump relay. You can test the relay and a fuse with an ohmmeter on the ohm setting. You can also use a voltmeter and check power to the relay and also to the fuel pump to test for 12 volts. If you have power to the pump but the pump is not running, it is likely faulty. If you don't have power to the pump, then either the relay or fuse is bad. If they test out ok, then test power from ECM.

These are the most common causes of a no start. If you have any bad sensors of any sort, it would likely set of the check engine light. Then the computer should be tested for engine codes which can be done with a scan-tool.

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2 Answers

97 oldsmobile achieva wont fire changed coil pack spark plugs cam sensor still wont start

Make sure battery has a full charge and battery connections all good.
If it cranks good but won't start, have a helper crank it while you visually check for spark at the spark plugs. If spark everywhere, use a gage and check proper fuel pressure and fuel injector pulse.
If you having a problem with more than one system, I want to check for rpm signal, that usually comes from the crank sensor. Not sure why you replaced cam sensor? I always want to check sensor wiring circuits before replacing anything. Don't replace anything unless your testing points in that direction.

Nov 04, 2016 | Oldsmobile Cars & Trucks

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1999 Sunfire 2.2 skips at 400 rpm

Here's a list of posible causes, I would lean towards a timing issue

1 Inspect Ignition Timing Incorrectly adjusted engine timing. grey_line.gif 2 Inspect Timing Chain Slipped or worn timing chain. grey_line.gif 3 Inspect Timing Belt Slipped or broken timing belt. grey_line.gif 4 Inspect Point Set Burned, worn or incorrectly set ignition points. grey_line.gif 5 Inspect Firing Order Spark plug wire(s) not connected in correct firing order sequence grey_line.gif 6 Inspect Distributor Worn, loose or incorrectly adjusted distributor. grey_line.gif 7 Inspect Crankshaft Position Sensor Damaged or faulty crankshaft position sensor or circuit. grey_line.gif 8 Inspect Crankshaft Timing Gear Worn timing gear(s) grey_line.gif 9 Inspect Spark Plug Wire Loom - Performance Improperly adjusted or worn/malfunctioning carburetor. grey_line.gif 10 Inspect Camshaft Position Sensor A Damaged or faulty camshaft position sensor will transmit incorrect ignition and fuel delivery information. grey_line.gif 11 Inspect Camshaft Interrupter-Magnet A Damaged or faulty camshaft interrupter-magnet will cause the camshaft position sensor to receive and transmit incorrect ignition and fuel delivery information. grey_line.gif 12 Inspect Camshaft Timing Gear Worn or broken camshaft gears may affect proper fuel intake, compression, combustion and exhaust. grey_line.gif 13 Inspect Distributor Cap Loose or cracked distributor cap grey_line.gif 15 Inspect Point Dwell Point dwell not within specified range grey_line.gif 16 Inspect Point Gap Incorrect point gap setting. grey_line.gif 17 Inspect Timing Set Slipped timing chain or worn timing gear(s)

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1 Answer

will a bad crankshaft position sensor cause the fuel pump not to get power to it ?

Crank sensor is for spark, cam is for fuel timing. Fuel pump is bad fuse/relay or pump. Year make and model?

Feb 15, 2015 | Cars & Trucks

1 Answer

i have no spark in the coilpack and n spark in the spark plug wire as well

A failed crank sensor can prevent your car from getting a spark.
When cranking the car's computer looks for a signal from the crankshaft indicating the crankshaft is turning to enable spark and fuel. A timing belt that has broken in some cars can cause no fuel and no spark since the crankshaft position sensor gets no signal that the overhead camshaft is turning.

Aug 14, 2014 | 2003 Ford Explorer

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