My 98 S10, stop and don't start anymore. the compression test is ok,but no spark....and the fuel pump have no power...that means 12 volts is interrupted in some place....but where????

Follow standard no-start troubleshooting procedures. Check fuel pressure and check for spark, etc.

Do It Yourself Diagnosis and Repair

Bad wire harness or bad pump

Hi, if the car turn over, and it don't start. Then it is like the engine don't get fuel. Or bad a spark plugs. Most common problem is the fuel pump going bad.

It could also be a bad fuse, but a easy way to check if the fuel pump is ok is to have someone stand at the back of the car when you turn the ignition. The fuel pump should make a buzzing sound for a few seconds. And if you don't start the car right away the fuel pump will stop.

If you don't hear any buzzing from the fuel pump/fuel tank then you have a bad fuel pump............

First thing I would do is check the basics, verify you have adequate fuel pressure by hooking up a fuel pressure gauge to your fuel rail assembly, next after you have verified thats ok check if you have spark going to your spark plugs, remove one of the spark plugs and hook a spark tester up to the spark plug wire, observe as your cranking the engine around if you see a spark on the tester or not, next if that passes you may have a cylinder compression problem, remove all spark plugs and perform a cylinder compression test, if all the cylinders seem to have low or no compression you have a valve timing issue, check and see if your timing belt is in proper time with the timing marks or if the belt is connected and has not broken, if you have a no spark condition check and verify your ignition module is getting 12 volt battery power with a test light, if you have 12 volts there next look into the crankshaft position sensor make sure the ohm resisitance is within the proper spec for your vehical if thats not correct replace the sensor with a new unit, finally if you find you have no fuel pressure check the fuel pump relay and fuse and verify there both ok if you find these to be both good, you more then likely have a bad fuel pump and that will require removal of the gas tank for further inspection of the pump assembly....

do you have compression on every cylinder? that may be your problem, that's the suggestion i'll make. pull each spark plug one at a time and do a compression check to make sure you have compression. if you don't have the tool, they are not that expensive to purchase. hope this helps you out!! although, if you do this test and it's good compression, i would lean more towards it could be out of time. meaning it could possibly have jumped time but you said the belt was good, it could have jumped a tooth or two which would mean a no start also.

Free Auto Repair Advice by Professional Mechanics




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Engine Cranks But Will Not Start

For an engine to run, you need three things to happen inside the engine, compression, fuel and ignition, without any one of these components the engine will not run. Follow the repair guide below:


Engine Configuration with Camshaft Operation

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Compression - Engine compression caused by crankshaft rotation and pistons moving up and down inside the engine block. If the timing belt or timing chain fails it will cause the camshaft to become out of correlation with the crankshaft or allow the camshaft to stop rotating. Either of these conditions will cause the engine to lose compression and sometimes cause internal engine damage.
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Fuel Delivery System - The fuel system includes: fuel pump, fuel injectors, pressure regulator, fuel filter and pressure lines. This system is used to supply fuel under pressure to the fuel injection system, the lack of fuel pressure or volume will cause the fuel delivery system to fail and the engine to stall or not start.
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Ignition Spark Delivery System - The ignition system components include: spark plugs, spark plug wires, distributor (if applicable), crankshaft angle sensor, camshaft angle sensor, ignition coil, ignition module, knock sensor and PCM (engine control module). The engine relies on the ignition spark to be delivered to the combustion camber at the correct time. If the ignition spark stops or is delivered at the wrong time the engine will not run or run poorly.

If your engine cranks but does not start follow this troubleshooting guide:
* Step 1 - Anytime you have a problem with electronically controlled components such as an engine, transmission, ABS brake, or SRS (supplemental restraint system, Air Bag) inspect all fuses using a test light and check the under hood power distribution center and under dash fuse panels. If all fuses test ok continue to the next step.
* Step 2 - To check for problems with electronically controlled components such as an engine, transmission, ABS brake, or SRS (supplemental restraint system, Air Bag) and the fuses test ok a trouble code scan is needed to identify any system trouble. Use a simple scanner tool to retrieve trouble codes and see if they relate to the specific problem, like a crank angle sensor failure code. If the trouble code present does not pertain to the immediate problem like an EVAP code ignore it until a later time, after the car is running. The reason we repair non-related codes after the engine is running is because sometime false codes can be triggered by the engine not running. Once the engine is running again the code present might cycle and turn itself off. You might say "if the engine doesn't run shouldn't it have a trouble code?" Sometimes conditions occur that will not be detected by the computer, example: if the fuel pump fails the computer cannot detect the failure, so the engine doesn't start and the computer thinks everything is ok with no codes. If no trouble codes are present proceed to the next step.
* Step 3 - The spark plugs in your engine are used to ignite the compressed fuel air mixture. If the condition of the spark plugs are fouled by excessive fuel or carbon the engine will not start, backfire or run rough. Remove all spark plugs to inspect their condition. Please use this spark plug condition reference guide to see how the spark plugs are operating.
* Step 4 - Determine if the engine has compression, this can be done a number of ways but the most complete method is to perform a compression check. Remove the spark plugs and perform a compression test on one cylinder. If one cylinder has compression then the remaining cylinders usually will be close to the same. Crank the engine over about 5 seconds, normal compression readings should be between 125 psi and 160 psi on each cylinder. If no or little compression exists additional tests will be needed. The most common reason for an engine to lose compression is a timing belt or timing chain failure. If low or no compression exists remove the oil fill cap and observe camshaft rotation when the engine is cranked over. If no rotation exists the timing belt or chain has failed. If your engine has a timing belt and you cannot see the camshaft easily remove the upper bolts to the timing cover and gain visual access to the belt, recheck cam rotation by cranking the engine over. Sometimes a timing belt or chain can jump causing the camshaft to lose correlation with the crankshaft and therefore causing low compression. The best test for this condition is to remove the timing belt/chain cover and inspect timing marks. If the compression is ok proceed to next step.
* Step 5 - Test the ignition system output, ignition systems can vary in configuration but operate on the same principal. Ignition systems can consist of a coil, pick up coil, crank angle sensor, cam angle sensor, spark plugs, spark plug wires, distributor cap, ignition rotor and a distributor and any variations of these components. An ignition coil is a voltage stepper coil that transforms a low voltage (12 volts) signal into tens of thousands of volts needed to jump the gap of the spark plug. This coil is activated by an ignition module triggered by using the camshaft/crankshaft angle sensor; timing is adjusted by the ECM (computer).

Hope helps (remember rated and comment this).

Engine Cranks But Will Not Start

For an engine to run, you need three things to happen inside the engine. Compression, fuel and ignition, without any one of these components the engine will not run.
Basic Checks:

A. Test Fuses. Test both under hood power distribution center and the fuse panel under dash. This is done with a test light tool. The test light should illuminate on both sides of the fuse, if not the fuse has failed and needs to be replaced.
B. Testing Fuel Pressure Test for proper fuel pressure with a test gauge on the fuel rail, most throttle body injection cars (TBI) are between 13 psi and 17 psi. and most (DPI) direct port inject systems are between 40 psi and 55 psi. If no or little fuel pressure is observed and there is 12 volt power present the fuel pump, the fuel pump needs replacing.
C. Checking Timing Belt Test for compression by removing a spark plug and insert a compression gauge. Crank the engine over about 5 seconds the gauge should read between 125 psi and 165 psi, if no compression is observed remove front engine cover to inspect timing belt or chain. Crank engine to observe cam rotation, if the cam does not rotate the timing belt or chain has failed. (note: if the timing belt drives the water pump it is best to replace the water pump at this time)
D. Test for Injector Pulse Remove injector connector to insert injector test light (node) or volt meter. Observe light flash or gauge pulse while cranking. If light/voltmeter doesn't respond, an ignition distributor/crank angle sensor (CKS) or an ignition module is most likely your problem.
E. Test for Ignition Spark Remove spark plug wire, insert an extra spark plug into end of wire, rest spark plug next to a ground source then crank engine. You should observe a blue spark between the spark plug gap and ground source. If no spark is observed, an ignition coil, ignition rotor or spark plug wires might have failed. (always keep hands away from engine when cranking)

1. Test Fuses. Test both under hood power distribution center and the fuse panel under dash. This is done with a test light tool. The test light should illuminate on both sides of the fuse, if not the fuse has failed and needs to be replaced.
2.Testing Fuel Pressure Test for proper fuel pressure with a test gauge on the fuel rail, most throttle body injection cars (TBI) are between 13 psi and 17 psi. and most (DPI) direct port inject systems are between 40 psi and 55 psi. If no or little fuel pressure is observed and there is 12 volt power present the fuel pump, the fuel pump needs replacing.
3.Checking Timing Belt Test for compression by removing a spark plug and insert a compression gauge. Crank the engine over about 5 seconds the gauge should read between 125 psi and 165 psi, if no compression is observed remove front engine cover to inspect timing belt or chain. Crank engine to observe cam rotation, if the cam does not rotate the timing belt or chain has failed. (note: if the timing belt drives the water pump it is best to replace the water pump at this time)
4.Test for Injector Pulse Remove injector connector to insert injector test light (node) or volt meter. Observe light flash or gauge pulse while cranking. If light/voltmeter doesn't respond, an ignition distributor/crank angle sensor (CKS) or an ignition module is most likely your problem.
5.Test for Ignition Spark Remove spark plug wire, insert an extra spark plug into end of wire, rest spark plug next to a ground source then crank engine. You should observe a blue spark between the spark plug gap and ground source. If no spark is observed, an ignition coil, ignition rotor or spark plug wires might have failed. (always keep hands away from engine when cranking)