First time poster long time viewer.

I have a 1999 high mileage Blazer that I have owned since new. My high school daughter uses this vehicle. Last week, took the truck to fill it up and no issues what so ever. Went to use the truck the next day and would not start. The engine cranks and almost catches but won't start. I followed the fuel pump pressure tech from the Captain and have the following results. Fuel pressure at the outgoing side of the fuel filter is 85 lbs. with the pump running. After 10 minutes the pressure drops to 70 lbs. Fuel pressure at service port is 64 lbs. with pump running and drops to 56 lbs. with no pump running. Pressure drops to 52 lbs. after 5 min and 51 lbs. after 10 min. With everything I have read, my pressures are good and not an issue with fuel delivery. Is this correct? What would make this truck go from a daily driver to a no start condition over night?

Thanks!

 

Welcome to the forum! Beautiful job checking fuel delivery! Your service port drop to 51psi after 10 minutes is a tad low, but it shouldn't cause any serious issues, and it certainly won't cause a no start condition.

Next step is check for spark while cranking: at the coil tower, and at each spark plug. Must be a blue, (not orange) rythmic spark. The coil and plug wires should jump at least a half inch gap. Post your results.

EDIT: With regard to your last question, everything works.... until it breaks

 

Thanks Captain! How do I check for spark at the coil? Can I remove the wire and hold close to see the spark?

 

Yup, remove the coil wire from the distributor, probably have to stick a screwdriver in the end, then prop it up, (don't hold it unless you want your hair curled), make a gap about half inch between the screwdriver and ground. Crank the starter and watch for spark.

 

The coil wire had an orange spark to ground. Does this suggest coil is weak?

 

How big was the gap? If the battery is not fully charged, the coil will not produce full output and may produce an orange spark. Did you check spark at the plugs?

EDIT: If you've been cranking it for a while, the battery might just need to a charge before we can continue diagnosing.

 

The gap was around 1/2". Battery is pretty good since it cranked the engine about the normal speed. I did not check the spark plug wires yet since they are a bit of a pain to get to. I guess that is next? Do I need to check all 6 plug wires?

 

Quite possible it needs a distributor cap & rotor. These things are fussy about them, if they aren't just right, it can cause a no start. Use AC Delco only!

 

I think I will start there. Thanks for all your help. I will post back with results from cap and rotor.

 

How old are the plug wires?

EDIT: if they're over 5 years old it's about time to replace them. If the coil wire has high resistance, it can easily cause the orange spark, and a no start.