Cranks but no spark

SOURCE: buick lesabre nightmare

Need to get a scan tool and look at the data stream while it is running for alot more info.Also any trouble codes.Sounds like initially,the engine isn't getting any fuel.I would have a pressure gauge connected to the fuel rail on the engine,so i could monitor the fuel pressure while all this is going on.Items to look at on the data stream would be timing,what timing is the PCM commanding for the engine.Also,have you checked for continuos power feed to the coils during this no start condition,and fire at the plugs while cranking.You could possibly still have spark,but maybe it is extremely weak?I have seen bad ignition switches cause weird problems before too.Many things power up through the ignition switch,just a thought.Have also seen bad PCM's cause strange problems..38 volts is a little on the low side for GM.Usually see those at,at least .50 and up,and rise steadily while pressing the throttle,up to just under 5.0 volts.Potentiometer with 5 volt supply.Vacuum leak can be checked with engine running at a steady idle speed,spray brake cleaner all around the intake manifold and listen for engine speed change.

SOURCE: buick lesabre no start

Hi you have replaced allmost everything ,(try fuel pump relay)

Ernest Stalker

• 53 Answers
• Posted on Jan 15, 2009

SOURCE: 97 Dodge Ram Pick up cranks ok engine won't run

try checking all the ground circuits comming out of the PCM. and its also not common for a ground driver in the PCM to fail on dodges. also i have seen crankshaft sensors short out and take out pcm communication. so i would start by unplugging any sensor that runs off the 5v supply until the pcm wil talk to the scanner. if you unplug a sensor and communication returns to scanner then replace the sensor. and dont forget to check for good power and ground at the data link conector and PCM

SOURCE: 1997 Dodge Ram 1500 5.2 liter won't start

I WOULD SAY IT IS THE COMPUTER {BRAIN} THAT IS WHAT SENDS THE FIREING ORDER AND VOLTAGE AND SETS THE TIMEING SPECK I WOULD SAY CHECK THE COMP

SOURCE: Have a 2003 Taurus, 3.0 engine that has a misfire

did you check the injector pulse on that cylinder and it also could be the pcm , i had a taurus and a sable with good coils stop firing 2 cylinders and it was the pcm ,the code it gave was secondary coil but changed the pcm and it worked fine