99 Yukon 5.7..... No start. Have spark and fuel(?)

[OR VietVet]

Coils have a very long life span and can surprise you when they finally let go.

 

[Shibbershabber]

I think this is only 2nd time Ive had one go out in over 20yrs

 

[Shibbershabber]

Well... the coil may have been a fluke.

Son of a ***** died on me in the middle of an intersection.... towed home.

Same thing. NO start.

Still have spark and could smell fuel.

Replaced the Crank and Cam pos sensors, just because I already had them in the garage. Still no start, but we can rule them out.

Fuel pressure is about 55psi

no start
no start
no start
no start...

then it started up fine and has a few times in a row after. WTF

Not currently driving it as its not reliable at all at this point.


What more could I be looking at/testing for here?

 

[OR VietVet]

You said smell fuel and pressure at 55 psi. What don't you have when will not run/start? Is fuel up to the spider but you have no pulse? Do you always have the spark when will not start or lose it intermittently? What color is spark when does have spark but will not start? Check all wiring inside the distributor for any bad insulation or crud in there.

Hell, maybe the ignition module gets hot and shuts down and the cools off and starts intermittently.

https://www.rockauto.com/en/moreinfo.php?pk=10951604&cc=1353721&jsn=2088

 

[Shibbershabber]

Hard to say.

I towed it home and checked the pressure a few days later. First few times I just turned the key on and got 55psi.... I thought maybe the pressure drops when I crank it so I tried to start it with the gauge attached and it fired right away and has started ever since... no chance yet to check pressure under a true no-start condition.

I have always had spark, fairly bright bluish spark

Wire harnesses looked good around the distributor. I looked it over when I installed the rotor and again when I installed the Cam pos sensor. Nothing looked burnt, bent, pinched or damaged at all.

I will probably throw that ignition module at it this week and see what that does... I think its literally the only sensor on the truck that hasnt been replaced at this point.


*** How can I check injector pulse???

 

[exp500]

Time for a fuel pump. pressure should be 60. May run ok at 58. Put a long hose on gauge so it sticks out back of hood and drive it. There are plenty of threads here for no start. It's time to diagnose your problem, not throw more parts at it. Do you gave a scanner, spark tester, multimeter, test light?

 

[Shibbershabber]

got a scanner and a multimeter