Bigtruck01

97 chevy 454 dually 4x4
so I'm back to working on my truck, last fall it was running crappy and I went to move it from yard to garage and it died. I have fuel, air ,spark, oil pressure moves up while cranking. It won't fire,tried starting Fluid and nothing. Only thing i did find is fuel pump relay isnt working so i put a jumper in. I replaced crank sensor and Icm. I tried using jumper from negative battery terminal to icm bracket to make sure I had a good ground to open injectors. But still always the same. Cranks won't start even with starting fluid. Any help would be appreciated.

73shark

Welcome to the forum. Moving your post to the correct truck section of the forum where you will get more views as this is the Welcome New Members section.

Bigtruck01

Ok thanks

Gumby22

Is this a manual or automatic transmission?

Double check for spark consistency at the #1 plug - make sure the engine has turned over at least 3-4 times and that spark is present every rotation.

The PCM will disable spark and fuel if it doesn’t receive a consistent signal from the crank position sensor. Oftentimes the first 1-2 engine rotations will allow spark and then it’s disabled after that.

Also try pulling DTC’s - even if the CEL isn’t on, codes can be stored.

I’d also recommend adding fresh gas and fuel system cleaner to the tank if the gas has been in there for as long as it’s been sitting.

Bigtruck01

• It's a 5-speed manual transmission. I have already changed fuel filter and put fresh fuel in it ,I had put my code reader on it it comes up with no codes and I put a screwdriver in number one spark plug and put it where I could see it from the cab and cranked it over probably a good 30 times and every time it has a really good spark jumping.
• I read somewhere about something on injectors won't fire because of something but I can't find it again to reread it. If that's the case what would cause that. With fuel air and spark it should run,, not even on starting fluid.

Gumby22

The PCM relies on the crankshaft position sensor signal for controlling spark and the fuel injectors. If you’re getting consistent spark, the PCM is also capable of pulsing the injectors.

But lack of fuel isn’t the concern. If it’s not firing on starter fluid, it doesn’t matter if the fuel injectors are pulsing or not - there’s something else going on.

Please clarify the no-start condition:

1) The engine sputters and attempts to start. Follow up - is there an overly rich smell when this happens?

2) The engine starts and stalls within a few seconds. Follow up - is the security indicator (should be in the top right corner of the instrument cluster) on steady or flashing?

3) The engine will not start but does not have an overly rich smell. Follow up - does the cranking speed of the engine remain constant or does it seem to vary in speed as the crankshaft rotates? Keep in mind this is assuming the battery is charged and capable of maintaining the cranking load.

Bigtruck01

Engine cranking stays the same, while not starting. No security light,I can kinda smell fuel but I wouldn't say overwhelming.

Gumby22

Have you checked compression or done any other testing to assess the mechanical condition of the engine?

I suspect the engine has a breathing problem - checking compression or cranking vacuum can at least confirm that air is moving through the engine.

Cranking vacuum should be 1-3 in*Hg.

Compression will probably be on the low end since the engine is cold, so make sure to check the neighboring cylinders for comparison.