CAN SOMEONE HELP ME PLEASE i HAVE ALREADY FORKED OUT 200 DOLLARS AND STILL NO RESULTS. i CANT GET NO SPARK. i HAVE REPLACED THE COIL AND MODULE, DISTRIBUTOR CAP AND BUTTON CHECKED FUSES AND PLUG WIRES EVERYTHING IS OK. ENGINE TURN OVER GOOD AND FUEL PUMP IS WORKING

 

Dude, calm yourself and stop shouting. The capslock key is not for general use, and will not inspire people to help you. It would also be beneficial if you posted this in the tech section for your year of truck. If a moderator sees this thread, hopefully they can move it for you.

Please post up what year your truck is, and what engine your truck has.

Have you done a fuel-pressure leak down test? Just because you can hear the fuel pump turning on does not mean it's reaching proper pressure. These trucks are notorious for fuel pressure problems. Use a fuel pressure tester to get accurate numbers. It needs to reach 60-66 psi with the key on, engine off (run position), and must hold above 55psi for at least 10 minutes when you turn the key off. Do this test, and report back with your numbers. Anything outside the range I said above and the engine will not fire.

 

Sorry about the caps lock I didn't mean to shout. It is a 05 blazer 4.3L 2wd. My dad did the fuel pressure test yesterday and said it checked good he didn't tell me the actual pressure. If I change the crank sensor will I have to adjust the timing.

 

I'm not sure if you'll need to adjust timing or not, but I believe that if you do you'll need a GM tech 2 scan tool to do it. Hopefully someone with more engine knowledge will chime in here. I would suggest that you make a more firm diagnosis before you continue throwing money at the truck. Post up more of your symptoms. Have you checked for trouble codes? Did the truck do anything abnormal before this problem started?

Double check the fuel pressure numbers. The trucks are very sensitive to proper fuel pressure, and have several problem points like the pump and fuel pressure regulator.

 

*Moved to '2nd Gen Tech'*

 

oil pressure sensor/sending unit perhaps? It only kills injector pulse on 1st gens, maybe it does more on a 2nd gen.

Crank sensor always possible.

Your not getting spark from plugs or coil or neither?

 

Don't quote me on this, but I don't think a bad oil pressure switch will prevent it from running on a 2nd gen. I had a no-start condition once, and was wondering about the possibility of a bad oil sensor. The information I received said that it wouldn't prevent it from running.


Also, how did you check the plugs? Ground them on an exhaust manifold while someone cranks?

 

Timing is not adjustable. Replacing the crankshaft position sensor will require a relearn to be performed on the PCM with a high $ scan tool, (dealer). Unless a DTC for the crank sensor is in memory, and the diagnostic flow chart specifically instructs you to replace the sensor, leave it alone, that's not the problem.

On 1997 and older S&T body, the oil pressure sending unit only provides an additional path for current to flow to the fuel pump when oil pressure is above ~7psi. It can not stop the fuel pump or injectors from operating. The circuit was eliminated on 1998 & newer.

We need to know the results of the fuel pressure test. Also, key ON, does the pink wire at the ignition coil show battery voltage?

 

Thanks for every ones help on this one. Let me get some checks done and I will post the results for the fuel pressure and voltage. Also a co-worker told me there is another coil down under the distributor is this true I only replaced the one up top also autozone tested my control module said it was bad so I bought a new one and still same results.
Yeah the truck ran great the day and prior no signs of any trouble.
Thanks again

 

Just do what the captain tells you to do, he will walk you through this with minimal money spent.