Hello, I have a 2003 Blazer ls 4 door 4WD. If I drive the blazer everyday it starts and runs fine. If it sits for more than one day, you have to crank for about 10 minutes to get it to start. During this cranking you can smell fuel and hear what sounds like an occasional backfire from the engine. I checked fuel pressure at the rail, 52 psi. After finding the excellent write up on this forum for testing fuel pressure, I checked fuel pressure at the fuel filter. Here it was 92 psi and 62 psi after 10 minutes. What should fuel pressure be at the rail?

 

After reading testing fuel pressure sticky again, I see that minimum fuel pressure at the fuel rail is 60psi. I assume there is a problem with the regulator or injectors. I think I will order the ac delco 217-3028 fuel injector kit so I will have the part when I take off the plenum. I would rather only do the job once. Is this the right part # for the 2003? Anything else I should check?
Thanks for your help

 

Your readings at the filter indicate that the pump is fine. 52psi at the service port indicates there's a problem in the plenum, either a leak, a faulty pressure regulator, or both. The AC Delco 217-3028 and the Delphi FJ10565 come with everything except the plenum gasket.


The backfire might be a problem with the distributor cap & rotor, (both need to be AC Delco).

 

If fuel pressure is the problem, any idea why the hard starts only occur after sitting for longer than one day?

I've seen pictures of the older style fuel injection with the poppet valves, they seem to just pull out. How do you remove the multi port injectors? Anything I should be aware of?

One other possible issue I have is sometimes after driving the blazer, once you turn it off you will hear a popping sound coming from the catalytic converter??
Thanks for the help

 

Without knowing the leakdown results at the service port, we can only guess. Excessive leakdown and low pressure can both cause hard start/long cranking times.


Removing the newer style injectors can be a chore, and it may involve removing the lower intake manifold.


Noises from the converter after a hot shut down is most likely the steel contracting when it cools.

 

The spider is leaking down and not holding fuel in the engine. Mine back fired and blew the pcv right off and broke the clip causing a huge vacuum leak. Replaced the fuel spider and starts every time. Make sure you grease the rubber fitting for the upper plenum. I had to go back and do it twice, thinking it was on all the way and a mechanics pointed out that it was not flush and was angled.

 

The 52 psi at the fuel rail in my first post was after the vehicle had sat more than 1 day. I checked pressure again today at the fuel rail. I have driven the vehicle everyday for 3 days including today. Pressure was 58 psi and dropped to 56 psi after 10 minutes. I will try to check again after the vehicle has sit for a day or so.

After sitting for a day or two I would think some leak down is normal, but the pump running for 2-3 seconds should bring pressure up to spec.

Any ideas??

 

Should I check fuel pressure at the fuel filter again after blazer has been sitting more than a day? Battery is only a couple months old, is it possible battery is draining after sitting?

 

The pump is fine.


At the service port, Key on, engine off, pump running, needs to be 60psi to 66psi, and it must remain above 55psi for at least 10 minutes after the pump shuts off. Your 10 minute leakdown to 56 is fine. Your 58psi, (regulated pressure) is low, and is caused by the regulator being set too low.

 

Thanks for your reply.

I don't understand why after sitting fuel pressure at the rail is 52psi. Thats when the hard start problem occurs.