I have a 1996 chevy blazer that will not pass emissions. They tell me that the evap system is not ready to test, any suggestions

 

*Moved to '2nd Gen Tech'*

 

Yup. The EVAP system has to meet certain criteria to do self testing. Some of those criteria is to be between 1/2 to 3/4 fuel level, to cruise at half throttle for 20 mins, stuff like that. If your tank is empty or full, it will not even come ready for testing. Its not a big deal. Just look up "EVAP readiness" in your search and see what the system needs to be able to test. This is the system that takes forever to come ready. When I took mine in for testing I had to drive it for about 3 days before it came ready to test.

Im not sure what a drive cycle is on your truck, but this is a universal one that should get all your systems ready.

RUNNING AN OBDII DRIVE CYCLE
The purpose of completing an OBD II drive cycle is to force the vehicle to run its onboard diagnostics. Some form of a drive cycle needs to be performed after DTCs have been erased from the PCM’s memory or after the battery has been disconnected. Running through a vehicle’s complete drive cycle will “set” the readiness monitors so that future faults can be detected (and potentially to pass the NYVIP re-inspection). Drive cycles vary depending on the vehicle and the monitor that needs to be re-set. Whenever possible, follow the drive trace prescribed for the specific vehicle/monitor in question. Some vehicle-specific drive cycles can be found in the vehicle’s Owner’s Manual.

The following “universal” drive cycle can be used as a guide to assist with re-setting monitors when a vehicle specific drive cycle cannot be located. This generic OBDII drive cycle begins with a cold start (coolant temperature below 122 degrees F and the coolant and air temperature sensors within 11 degrees of one another). This condition can be achieved by allowing the vehicle to “sit” overnight, and then by beginning the drive cycle the next day. Most drive cycles will be difficult to follow exactly under normal driving conditions, so the driver should exercise caution, road safety, and courtesy to others.

• <LI class=paragraph1>Start the engine. Idle the engine in drive for two and a half minutes with the A/C and rear defroster on. <LI class=paragraph1>Turn the A/C and rear defrost off, and accelerate to 55 mph at half throttle. <LI class=paragraph1>Hold at a steady speed of 55 mph for three minutes. <LI class=paragraph1>Decelerate (coast down) to 20 mph without braking or depressing the clutch. <LI class=paragraph1>Accelerate back to 55 to 60 mph at ¾ throttle. <LI class=paragraph1>Hold at a steady speed of 55 to 60 mph for five minutes.
• Decelerate (coast down) to a stop without braking.

You can also have a look at this thread here https://blazerforum.com/forum/2nd-generation-s-series-1995-2005-tech-41/obd-ii-never-comes-up-ready-help-42141/#post315803

 

ok thanks for tge help today was the fourth time i went for emissions i have drove the truck for a week since the last test. guess i will keep driving and retesting