Hello all, I have a 2001 Blazer Zr2 with 114,000 miles on the clock. Ever since I bought it (6 months ago) it has always had a hard start problem and will crank 5-6 seconds before eventually starting. Once it is started it will stay running with no issues. I have replaced the intake manifold gasket, fuel filter and the spider (AC Delco) while I was in there.

I ran a fuel pressure test last night and it is not good. It will prime to 60psi and then immediately drop off and is running at 52psi when running. Once shutoff it will drop within 3 seconds from 52 to 0psi. Leaking Spider? bad check valve fuel pump?

Also, recently getting P0446 SES code. My code reader isn't advanced enough to give me any further specifics than that. I know it's an EVAP code but it looks like it can be 6 different things for that one code.?????

Here is a video link to my fuel pressure test that will hopefully help! Thanks in advance.

 

The only way to tell which one is at fault is to dead end the fuel pump ahead of the spider per the sticky at the top of this forum. Really in your case I would test and report all four values indicated in the sticky. Then the diagnosis will be complete, and will be a piece of cake to know what is wrong. Does require you to make up some fittings and do some work, but this is described in the sticky. Note that if you have the upgrade MPFI spider, about 58psi has been shown to be normal for Key on / engine off (value stated in sticky is for factory fuel pressure regulator on the poppet style spider).

https://blazerforum.com/forum/2nd-ge...eakdown-88305/

 

PO446 is an evaporative emissions code. PCM is doing a test to see if your gas tank will hold vacuum and it fails the test. Loose gas cap is common problem. Gas tank vent valves are another common problem. Know that a lot of specific conditions must be met for the test to run and code to set. So you may think it is fixed and then SES light will suddenly come on. Check for loose gas cap first. This one is a bit difficult to diagnose without the proper equipment. Then if you want to throw a couple parts at it, replace gas cap first and then then purge valve if gas cap doesn't fix it. Leaks in the filler neck/hose are also fairly common.

Any code can affect operation of the vehicle by PCM forcing into a failsafe mode, but this P0446 shouldn't be affecting your starting (so this is a separate problem).

https://blazerforum.com/forum/diagno...plained-35143/

 

Lesmyer thanks for your help, when I was doing the Intake Manifold gasket job the hose (one with quick disconnect fitting) that goes to the Evap solenoid (intake) on the passenger side of the engine broke because it was brittle. I have it just shoved on there for right now and have a hose ordered to replace it. Would it be enough of a leak for it to trip the SES? I have it just pushed on but obviously isn't locked into place because the white clip broke.

 

If it allows air to leak into the fuel tank it will fail the evap tests when they do run.