nbkk43f
Member
- Joined
- Aug 16, 2023
- Posts
- 37
- Reaction score
- 77
- Location
- charlotte, nc
- First Name
- Nick
- Truck Year
- 1977
- Truck Model
- c10
- Engine Size
- 5.7
Ok, it's time for the experts! My extremely reliable 96 pickup (~90k miles) has decided to not start. The truck doesn't see many miles and is mostly used around our property, not uncommon for it to sit for weeks without use - regardless, he always starts right up. I went to move it the weekend before last, it started right up, I put it in reverse and it wouldn't take any fuel and just shut off. Tried a restart, nothing.
I got it over to my shop and figured it was the fuel pump (i put a cheapo in it when I replaced it back in '19). Checked the fuel pressure, goes to about 45psi when I turn the key on and maintains it - when cranking it goes up to around 55psi.
I shot some fuel down the throttle body, hit the key and it fired up (briefly), so that eliminated "no spark". I also checked for codes (CEL isn't illuminated) and it came up empty.
I tried a new ignition control module, no luck. I then started doubting the fuel injection (spider) assembly and fuel pressure regulator. Pulled the plenum (fun job) and removed the FI assembly, cleaned everything up and replace the fuel pressure regulator while I was in there. I'm a carb guy so bare with me on this...I put 12v to each one of the injectors in the assembly and they all clicked as if they "work", besides why would all 8 go out all at once anyway?
Put everything back together and insured all the sensors were plugged back up. Crank, and still nothing.
So now lets start swapping out some parts...first on the list was the crankshaft position sensor, nope, still no start...
Throttle position sensor - nope...
Idle air control valve (why not) - nope...
So maybe I'm not getting any voltage to the main FI harness - I unplugged that and tested a few of the injector connections for voltage on crank, all that I checked had 12+ volts. For giggles I shot some more fuel down the carb to see if it would crank - yep, popped right off.
At this point, I'm at a loss and would greatly appreciate your thoughts!
Thanks in advance!
I got it over to my shop and figured it was the fuel pump (i put a cheapo in it when I replaced it back in '19). Checked the fuel pressure, goes to about 45psi when I turn the key on and maintains it - when cranking it goes up to around 55psi.
I shot some fuel down the throttle body, hit the key and it fired up (briefly), so that eliminated "no spark". I also checked for codes (CEL isn't illuminated) and it came up empty.
I tried a new ignition control module, no luck. I then started doubting the fuel injection (spider) assembly and fuel pressure regulator. Pulled the plenum (fun job) and removed the FI assembly, cleaned everything up and replace the fuel pressure regulator while I was in there. I'm a carb guy so bare with me on this...I put 12v to each one of the injectors in the assembly and they all clicked as if they "work", besides why would all 8 go out all at once anyway?
Put everything back together and insured all the sensors were plugged back up. Crank, and still nothing.
So now lets start swapping out some parts...first on the list was the crankshaft position sensor, nope, still no start...
Throttle position sensor - nope...
Idle air control valve (why not) - nope...
So maybe I'm not getting any voltage to the main FI harness - I unplugged that and tested a few of the injector connections for voltage on crank, all that I checked had 12+ volts. For giggles I shot some more fuel down the carb to see if it would crank - yep, popped right off.
At this point, I'm at a loss and would greatly appreciate your thoughts!
Thanks in advance!
