long crank

[HotWheelsBurban]

It might be something with the vapor canister? My Burb is doing this lately, moreso when it's hot outside. It has 200K on all the original fuel injector parts so I figure the FPR or poppets may be a bit weak. It only does it if it's been sitting a few hours, or overnight, or if it's really hot and humid. And holding the key in Run for a few seconds seems to prime it enough to avoid the issue.

 

[Nad_Yvalhosert]

Bank 1 sensor 3? Interesting.

That's legit. I've seen that in a scan tool. Some of the 5.0L, Federal emission equipped trucks, in the early Vortec years had a y-pipe and a single converter. B1S3 is the single downstream O2 sensor

 

[Nad_Yvalhosert]

I’m having the same issue on my 98 350 replaced spark plugs and wires, cap and rotor, ignition coil, and icm. My fuel pressure is at 60 with key on and 53-54 while running. It doesn’t hesitate at all runs good just the long crank time with door on gas pedal is where I’m stuck.

That fuel pressure reading is too low. Should be 60-66.

 

[SUBURBAN5]

That fuel pressure reading is too low. Should be 60-66.

So say you have no issues in your fuel system but still read low fuel pressure 53-55psi driving around. What can you do to make it read 65psi? I understand there can be restrictions or defects but I cant find anything wrong with my fuel line for the life of me. I was thinking of adding a fuel regulator to return line but have no idea on what type and where to splice it in.....

 

[Nad_Yvalhosert]

So say you have no issues in your fuel system but still read low fuel pressure 53-55psi driving around. What can you do to make it read 65psi? I understand there can be restrictions or defects but I cant find anything wrong with my fuel line for the life of me. I was thinking of adding a fuel regulator to return line but have no idea on what type and where to splice it in.....

Since there's already a pressure regulator under the plastic upper plenum, theres no need to splice in another one.
However, they are replaceable.

 

[stutaeng]

So say you have no issues in your fuel system but still read low fuel pressure 53-55psi driving around. What can you do to make it read 65psi? I understand there can be restrictions or defects but I cant find anything wrong with my fuel line for the life of me. I was thinking of adding a fuel regulator to return line but have no idea on what type and where to splice it in.....

I know spec is like 60 psi, but my 4.3 truck always read around that 54-55 psi and it seemed like it was just fine.

When I changed the engine (did a 5.3 swap) I was troubleshooting something else and plugged the return line and pressure shot to like 75 psi, so I knew pump was capable of producing much more pressure than what regulator was reducing to.

My other truck with the 5.7 engine also reads about the same 54-55 psi. At some point I changed to the MPFI, but it started just fine under that pressure with the old poppet injectors. I had to replace them because one was stuck closed.

My point is that fuel pump is very likely capable of producing much more "head" of pressure than what your guage reads...so don't automatically condemn the pump...you know what I mean?

Are you running the MPFI set up?

 

[Schurkey]

How many of you test your fuel pressure gauge, to see if the gauge on your test equipment reads correctly?







I didn't think so. Unverified test equipment is a great way to screw the pooch. Pressure and vacuum gauges of all sorts--fuel pressure, cranking compression pressure, intake-manifold-vacuum gauges--ALL NEED TO BE VERIFIED NOW AND THEN.

 

[SUBURBAN5]

I know spec is like 60 psi, but my 4.3 truck always read around that 54-55 psi and it seemed like it was just fine.

When I changed the engine (did a 5.3 swap) I was troubleshooting something else and plugged the return line and pressure shot to like 75 psi, so I knew pump was capable of producing much more pressure than what regulator was reducing to.

My other truck with the 5.7 engine also reads about the same 54-55 psi. At some point I changed to the MPFI, but it started just fine under that pressure with the old poppet injectors. I had to replace them because one was stuck closed.

My point is that fuel pump is very likely capable of producing much more "head" of pressure than what your guage reads...so don't automatically condemn the pump...you know what I mean?

Are you running the MPFI set up?

I understand what you mean. Yes it's a mpfi. Everything practically new just periodically check fuel pressure. Runs good for the most part lol. I've just wondered why everybody says 60-66psi and I've never achieved that . Highest I've seen is 60 but that like on the first prime, then it kicks down to 55 and stays there for the most part.

 

[SUBURBAN5]

Since there's already a pressure regulator under the plastic upper plenum, theres no need to splice in another one.
However, they are replaceable.

Regulator new. I figured adding one to the return would help bring up the pressure on the inlet side. But makes sense. No need to 2 lol

 

[stutaeng]

I understand what you mean. Yes it's a mpfi. Everything practically new just periodically check fuel pressure. Runs good for the most part lol. I've just wondered why everybody says 60-66psi and I've never achieved that . Highest I've seen is 60 but that like on the first prime, then it kicks down to 55 and stays there for the most part.

@Schurkey makes a good point about checking the actual guage itself...I think something happened to mine and I had buy another guage from the local parts store, but I don't recall being any difference in readings in my case.

I actually dislike those pressure guages. The hose is really short and when you tighten up the fitting it seems like the guage dial always wants to face back. I've thought of looking for like a 3' extension or rigging my own. I've seen YT videos and the guys with the MAC and similar pro guages and those come with long hoses. Would be nice to stick to your windshield and go driving to see what pressure is under actual driving conditions for diagnosing.