Vehicle won't start
You will have to pinpoint what the engine is missing Spark / Fuel / Compression
All three of these are tested when the engine is being cranked over. There are two way of checking for fuel. Fuel pressure and fuel trigger. Both are very important and must be present for the engine to start. Fuel pressure is self explanatory. You just hook up the gage and see what the reading is. Fuel trigger is check with a noid light. The injector gets unplugged and the noid light gets plugged in to the injector clip. With the engine cranking over, this light must blink. This is the signal to the injectors from the computer. You can have all the fuel pressure in the world, but it wont matter if the injector is not pulsing gas into the cylinder like it should.
Compression tester, spark tester, fuel pressure gage and noid light are all accessible at your local auto store. All three tests play a very important part in diagnosing a no start condition. Be extremely careful when doing these tests.
Additionally, keep in mind that the four most common Check Engine Light scenarios and what to do:* The Check Engine Light turns on and off or flickers.
If the Check Engine Light comes on in the city but goes off on the freeway, then the fault is present during city driving conditions. Pay attention to whether or not the vehicle runs or drives any differently when the Check Engine Light illuminates. If vehicle performance does change, drive the car as little as possible and take it to be checked by a service professional as soon as possible. If there is no change in vehicle performance, you can drive home, but have it inspected as soon as possible. In this condition, you run a risk of the vehicle dying or not starting.
* The Check Engine Light comes on and stays on.
If the Check Engine Light illuminates constantly during driving with no noticeable driving or performance problems, there is a permanent fault in the emission control system. When this happens, the computer that controls the emission system usually has a backup program that runs while the fault is present. (These backup programs are often referred to as "limp home" mode programs.) You should get the vehicle serviced as soon as possible, but in most cases, the vehicle will continue to operate, though you run a risk of it dying or not starting.
* The Check Engine Light illuminates, stays on, and there are performance problems.
This means that a vital component of your emission control and engine management system has a serious problem. It usually involves a component or system needed for the vehicle to run at all. In most cases, drive the vehicle as little as possible. In many cases, the vehicle is not safe to drive at all -it could stop or stall out at any moment. It is best to pull over to a safe place and have the vehicle towed to an automotive diagnostician for a thorough inspection and repair.
* The Check Engine Light light comes on and blinks in a steady pattern while driving.
Don't confuse this steady pulsing of the Check Engine Light light (usually one or more flashes per second) with a flicker (see above). The Check Engine Light may stay on steadily or it may flash when the vehicle is accelerated. This is very serious. There is a severe failure of the emission control system that is causing the engine to misfire to the point that the catalytic converter is damaged each time the Check Engine Light flashes. It may mean that the catalytic converter is overheating to the point that it will glow red or, in extreme cases, start a fire on the underside of the vehicle. Immediately pull over to a safe place and have your vehicle towed to an automotive diagnostician for repair. Vehicles can be severely damaged and even destroyed by fire if this condition is ignored for too long.
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Jun 08, 2012 |
1987 Oldsmobile Delta 88