97 5.0 Sierra Won't Start

[BULLITTR6]

Ok, I have replaced the fuel filter, fuel pressure regulator (grrrr), cap and rotor. No OBDII codes present. Fuel pump whirs to pressurize with key on. Fuel squirts out at test port next to F/I. Coil tested good. Nice white/blue spark from plug tester too. Engine just spins but never even trys to catch fire. What the heck is going on? Sure could use some help. Thanks

[blabhern]

timing issue? Does the engine turn or are you just hearing the starter?

[BULLITTR6]

Well, it turned out the fuel pump was only putting out 40 psi instead of the 60-66 psi required. I mistakenly assumed that fuel under pressure at the test port and the sound of the pump pressurizing meant it was ok. Wrong. The pump can degrade as opposed to just quitting. I feel stupid for not buying a $40 guage to test the actual pressure. Live and learn I guess.

On the bright side, there are a whole lot of zero time items installed I shouldn't have to worry about for quite a while ! Too bad it took a trip to the dealer to figure it all out.

[BULLITTR6]

Originally Posted by blabhern

timing issue? Does the engine turn or are you just hearing the starter?

I did consider timing as a possibility, but it's my understanding that after 1995 the timing is controlled by the PCM and the distributer is not adjustable. I checked for compression pulses at the tailpipe to make sure the timing chain hadn't broken. That happened to my dad's bronco and the engine would spin over freely because the valves were all bent and no compression was achieved.

[blabhern]

Yes it is computer controlled but it could be so far out that the computer couldn't compensate. Glad to hear you got it fixed. Fuel pumps aren't cheap for our truck though.