My truck has always been temperamental. If I let her set too long, she always took a try or two to crank. But I just rebuilt the tranny and t-case, and she seems more so lately. It's not like her to not crank when I jumped out of her just a few minutes prior, but she does now. It's not all the time, either. It has been about three times in the past week. I worry she may simply not fire at all sooner or later. I know that if the crank sensor or the cam sensor die, she won't wake up. I replaced the crank sensor about a year ago, though. I believe the cam sensor is still original. When it happens, she spins over fast and hard, but there seems to be no fire. I have, so far, been able to overcome it by turning the key off and trying again, but today she took four tries, and I have no way of towing her. But I have no money to simply replace sensors for no reason. Any help?

 

Weak spark? Worn plugs? Low Compression? Low fuel pressure? Bad ground(s)?

 

Lets see:
I replaced the plugs and wirea when I replaced the crank sensor, about 10 - 15k miles ago.

I am pulling a steady 17" of vacuum.

However, I have not checked the ground. I will do that soon, but I've lost the ground before and it wouldn't even spin over (but the radio worked, weird huh?)

And I can hear my fuel pump engage, though I will check the pressure, but it's hard to predict when she'll do it again.

 

You'll always hear the fuel pump engage unless it's totally shot. Poor fuel sending unit ground could cause it.

 

If y'all were betting men, what would you say the chances are of my cam sensor going out? It IS one of the deadly sensors, right? Would you replace it to remove the possibility? I would get mine straight from the dealer, I learned my lesson with the crank sensor. By the way, how do you know these two sensors are in fact bad? Will the ECM sense it?

 

You can test them by checking resistance across the terminals. I don't know the exact spec that they should be but I do know if upon checking for resistance, if it reads Zero or Infinite then the sensor is bad.

 

Alright, I hooked my fuel pressure gauge up and it read 50 psi. I let her coll for about 30 minutes and tried again. This time, it slowly crept up to 30 psi. I tried cranking in this state and no fire. As it turned over, the pressure built to 40 psi, and she fired then. So I think I've found the culprit. I have a new fuel pump and I'm installing it now. Wish me luck!

 

Hope that was the problem!

 

Well, that fixed the fuel pressure problem, but she still doesn't wanna crank sometimes. What should I try next?

 

sounds like you have a pressure regulator problem. could turn key to run position then off then try starting it. should fire up. cycling the key lets the pump prime the system.