Fuel Pressure Drop
 

Hey everyone. Like many others on here I have developed a cold start issue with my 2001 4x2 4.3l blazer. It ran fine then wouldn't start one day and I had it towed. Mechanic said it started right up for him and couldn't find an issue. I get it back and a few weeks later the same problem, wont start in the morning. I've tested the fuel pressure at the schrader (sp?) valve and have a strange problem. When I first prime the pump the gage reads ~60 psi but within one second drops to 50 psi and holds steady. Is this an issue with the pump not sustaining pressure or is there a bypass valve somewhere that releaves pressure if you don't crank the engine? Or maybe a faulty gage?

Also, I tried getting it to start with starter fluid and still no avail. Just a lot of cranking but no start. Getting desperate, any thoughts?

Thanks for the help.

I'm not an expert on the subject, but it sounds like it might be the fuel pressure regulator.

Working through all the steps in 96+ Fuel System Diagnosis will help you pinpoint the problem.

60 or 50 lb is no bid diff for "starting up". Also, if starter fluid still does not make it fire, I'd say you are getting fuel into the motor.

Have you checked for spark?

I checked one cylinder quickly and saw spark but I will be checking more of them more thoroughly next. If spark is present I guess that leaves an injector or spider assembly issue?