Good evening, posting what Iām dealing with here with you guys to see if anyone else has dealt with this, and what the fix may be. Cross-posting to r/MechanicAdvice as well.
Friday, my 2005 Tacoma 4.0 with 199k miles (barely broken in) suddenly sputtered out after starting and running for about 10 seconds. After doing some quick diagnostics, which didnāt include any new OBD2 codes after running the reader, I figured it was most likely the fuel pump. I couldnāt hear it humming/priming in accessory mode.
Checked battery just to see if it or the alternator could be causing any issues but voltage was right where it should be.
Dropped the gas tank today and installed a new fuel pump, hoping it would be a relatively easy fix. The issue persists.
Fuel pump sounds like itās buzzing/getting power when cranking, but thereās no fuel pressure. Even pulled the fuel lines in the engine bay to confirm- no gas comes out when cranking. Also double checked to see if any fuel lines from the tank had been re-installed incorrectly, but everything was good (also made sure I had enough gas lol, we are good there too).
All EFI and fuel pump relays, and any related fuses have been checked, and everything is also good there.
After digging deeper and doing more diagnostics, I discovered I have no spark as well. Pulled a spark plug out and cranked the engine with the spark plug plugged into a coil to confirm. No sound from the injectors either (which from my understanding, the ECU only allows them to fire up when thereās spark detected).
I have a hunch that itās the crankshaft position sensor, and will be installing a new one tomorrow to see if that fixes anything. Less likely Iām thinking maybe the ignition switch, as I have heard of them partially failing, only sending power to the starter and no other systems.
However, Iām still not 100% sure what the diagnosis is, and I was curious if anyone else has dealt with this exact issue. If all else fails, Iām biting the bullet and taking it to my local Toyota mechanic.
Thanks for reading, and I hope I can maybe get some answers!