Just bought this truck recently and have found in the morning after sitting overnight or for a day it occasionally won't start. This doesn't happen every time it sits and doesn't seem to be related to temperature or moisture. What is constant is that if it starts first thing it runs great all day.
The starter and battery work great because they crank the engine over quickly but it doesn't cough, sputter or anything when it won't start, just cranks and cranks. This problem occured before I changed the air filter, spark plugs, wires, cap and rotor and still occurs with equal frequency after the tuneup. On one occasion I pulled a spark plug and grounded the electrode with the wire hooked to the plug and there was a strong, bright spark every second or so of cranking so it appears the ignition systems works as it should. The fuel pump primes when the key is turned to ON so the relays that power the ignition and fuel pump seem to be doing their job.
I replaced the fuel pump (which is a combination pump, filter, pressure regulator, check valve) and it started and ran fine the day I changed it but this morning it would not start again.
I got my hands on a fuel pressure tester and found that when the ignition key was turned on after depressurizing the system it went to 46psi (book says 44-54psi is "normal") and when I finally got the truck started it ran steady at 50psi at idle. After I turned the truck off it went down to 46psi. I waited 5 minutes and it was at 44psi. Now, almost an hour later its at 40psi. (the Haynes manual says you have a leak somewhere if the pressure drops below 30psi in 5 minutes, but my pressure is holding much longer than that, although I don't know how well a "normal" system holds pressure.)
I plugged the block heater in this morning (it was about 40F, 10C, not cold) and the truck eventually did start (sometimes it starts later in the day at random, not sure if the block heater does anything or not). At that point my Scanguage told me the coolant temp was 96F. None of the fuel lines, rail, injectors leak externally that I can see by visual inspection (though I'm no expert there) and I'm at a loss as to what else the problem could be.
The starter and battery work great because they crank the engine over quickly but it doesn't cough, sputter or anything when it won't start, just cranks and cranks. This problem occured before I changed the air filter, spark plugs, wires, cap and rotor and still occurs with equal frequency after the tuneup. On one occasion I pulled a spark plug and grounded the electrode with the wire hooked to the plug and there was a strong, bright spark every second or so of cranking so it appears the ignition systems works as it should. The fuel pump primes when the key is turned to ON so the relays that power the ignition and fuel pump seem to be doing their job.
I replaced the fuel pump (which is a combination pump, filter, pressure regulator, check valve) and it started and ran fine the day I changed it but this morning it would not start again.
I got my hands on a fuel pressure tester and found that when the ignition key was turned on after depressurizing the system it went to 46psi (book says 44-54psi is "normal") and when I finally got the truck started it ran steady at 50psi at idle. After I turned the truck off it went down to 46psi. I waited 5 minutes and it was at 44psi. Now, almost an hour later its at 40psi. (the Haynes manual says you have a leak somewhere if the pressure drops below 30psi in 5 minutes, but my pressure is holding much longer than that, although I don't know how well a "normal" system holds pressure.)
I plugged the block heater in this morning (it was about 40F, 10C, not cold) and the truck eventually did start (sometimes it starts later in the day at random, not sure if the block heater does anything or not). At that point my Scanguage told me the coolant temp was 96F. None of the fuel lines, rail, injectors leak externally that I can see by visual inspection (though I'm no expert there) and I'm at a loss as to what else the problem could be.
Oct 25, 2010 at 12:18 PM
