I have seen this topic many times in the past few days and I just wanted to make things just a little more easy for people trying to figure out these "no start" problems... Seems alot of people are getting mis-directed in troubleshooting and going in wrong directions due to improper procedure... I'll make this plain and simple so it can be understood easily.. This is more directed towards more "newer" fuel injected cars OBDI/OBDII equipped... and take in mind, these are just the basics for determining a spark condition...

Certain parameters need to be accomplished to make the car start and run, efficiently and sometimes in-efficiently.. they include..

Spark...this includes sufficient battery power..
Fuel...
Air...
Compression.... this is part of the timing folks..
Combustion...see above..

The first and easiest task would be to determine if the spark plugs are getting power and "sparking" while cranking the motor in a "no start" condition"... to determine this...

Remove a spark plug wire from a spark plug.

Insert an old spark plug or remove a spark plug and place into the plug side of the spark plug wire..(screwdriver will work as well)...

Ground the spark plug by placing/laying it on a sufficient ground somewhere on the motor, ground straps, power steering/alternator mounting brackets work well here.. the valve cover doesnt always work well due to bushings, coatings, paint,gaskets etc... do not lay it directly on the ground, but rather give it a 1/4 inch clearance so you can visually see the spark "jump" while cranking the motor...

Now try starting/cranking the car while observing the spark plug...

Do you see the spark?...
If "yes" see next step..
If "no" see next step..

This is where the mis-direction starts and confusion begins...

NEXT STEP....

Next step would be to determine if you have voltage and ground signals going to your fuel injectors.. I never hear people considering this and is as important as determining "spark/no spark"conditions for the fact the fuel injector signal is controlled via the ECU... This narrows down troubleshooting considerably and only take a couple minutes to determine...

Pry out the clips that secure the Fuel Injector Connector and remove the connector. The connector will have 2 wires, one for the + signal and one for the - signal.. place a test light in place of the injector and in-between the 2 wires and visually see if the light "flashes" while cranking the motor..

If it flashes "on" and "off" while cranking, it means that the ECU is working and receiving the proper inputs from multiple sensors that are needed in making the car start...

If "NOT FLASHING" Check the...

ECU..
CYP/CAM sensor located in the distributor..
CFK/Crank Sensor..

If it does NOT FLASH, then it would mean the ECU is NOT working properly or NOT receiving input from needed sensors.. start with checking the involved sensors and most importantly, the ECU, and ECU power inputs along with the ECU fuses....

Now we have an accurate starting point...

If Fuel injector pulse exsists and the test light is "FLASHING"

You would then concentrate your troubleshooting on the Ignitor, coil, distributor cap,rotor,(where applicable)plug wires and spark plugs.....distributor signal from ECU plays a part here, but isn't usually the problem..


Again...this is just a starting point in troubleshooting no spark conditions and DOES NOT include fuel pressures,main relay(which usually fails on the fuel side),PCV,mainifold vacuum,etc, etc,etc.. these components will not affect spark or a non existent FI signal...

END......


And if I forgot or messed up something, then feel free to straighten my tired *** out.. I just would like people to understand a little more and any help is appreciated.. Hope this helps someone...

Breakstuff

 

Well written!

 

Good stuff.

 

i have a question, if you're cranking the engine to test for spark and the wires of the fuel injector, won't that eventually start the engine? should the engine start while testing for spark?

 

Well if the car was starting and running, then theres is no need to check for spark.. hence the title... "No Start,No Spark".....