Extended crank when warm or hot on crate GM L31

[454cid]

The valves look like This.
One on each corner of the tank with a tee and a hose that runs to the charcoal canister.

I definitely don't have anything like that. Are you still talking about a GMT-400?

 

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I definitely don't have anything like that. Are you still talking about a GMT-400?

Yes. A 410 to be specific. This is a suburban.

 

[454cid]

Yes. A 410 to be specific. This is a suburban.

Oh, that probably explains it. The SUVs are a little different here and there.

 

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I definitely don't have anything like that. Are you still talking about a GMT-400?

Oh, that probably eaplains it. The SUVs are a little different here and there.

Does your vent line run to the center barb on the fuel pump module? I think that’s how my pickup is.
Anyways… fuel issue solved. Extended cranking is not unfortunately.

 

[454cid]

Does your vent line run to the center barb on the fuel pump module? I think that’s how my pickup is.
Anyways… fuel issue solved. Extended cranking is not unfortunately.

Yes, I have a single line that runs to the pump.... I don't recall which connection it is on the pump, but probably the center. Too bad you're still getting an extended crank.... when I replaced my pump, my extended cranking went away. Have you checked fuel pressure? Not only was my pump wearing out, but I suspect my electrical connection was bad. I replaced the pig tail with the 2nd design, and made sure of my ground.

 

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Yes, I have a single line that runs to the pump.... I don't recall which connection it is on the pump, but probably the center. Too bad you're still getting an extended crank.... when I replaced my pump, my extended cranking went away. Have you checked fuel pressure? Not only was my pump wearing out, but I suspect my electrical connection was bad. I replaced the pig tail with the 2nd design, and made sure of my ground.

Yeah it’s got the new conmection. Have checked the fuel pressure countless times and have put two different Delphi pumps in there. Have even run two temporary wires to battery for pump. Same old story. It just seems so much like a leak down problem… but it isn’t.

 

[Schurkey]

You have appropriate fuel pressure DURING the long-crank problem?

Do you have RPM signal showing on the scan tool, DURING the long-crank? How about actual spark on a spark-tester calibrated for HEI?

 

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You have appropriate fuel pressure DURING the long-crank problem?

Do you have RPM signal showing on the scan tool, DURING the long-crank? How about actual spark on a spark-tester calibrated for HEI?

The fuel pressure is 58-56 when cranking all the time. Hot or cold.

I used a spark tester with the gap set at 25 (is that what you mean by calibrated for HEI?) on a couple plugs and it was a clean blue spark. I didn’t do this when it was acting up, because it’s hard to pin down when that will happen. Given one turn of the key it won’t start, and the next it will. But I did test it hot and cold to no change.

 

[454cid]

The fuel pressure is 58-56 when cranking all the time. Hot or cold.

I used a spark tester with the gap set at 25 (is that what you mean by calibrated for HEI?) on a couple plugs and it was a clean blue spark. I didn’t do this when it was acting up, because it’s hard to pin down when that will happen. Given one turn of the key it won’t start, and the next it will. But I did test it hot and cold to no change.

.025"? That's really small.

 

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.025"? That's really small.

No it’s 25 on the spark tester… not sure what the units are. I think it’s meaning kV. Anyways… it translates to about .65 inches gap between electrode and cathode of the tester. Sorry for the confusion…