No-Start Vortec 350

bEnC10

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I did get a new pair of spark plugs maybe 2 weeks ago when I put them in the block permanently but I can try some new ones. They came pre gapped .30 I think, anyway so I have spark, Compression and fuel. Could it be the ECU? Or any electrical component?
 

HotrodZ06

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I just bought a truck with the same issue. Guy I bought it from couldn't make it startup. After a compression test pulled the cap and rotor was 120° out. Fixed that still no start check fire at coil, it was good. Moved to fire at #1, no fire. Replaced cap with known good cap runs like a champ now.
 

stutaeng

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I did get a new pair of spark plugs maybe 2 weeks ago when I put them in the block permanently but I can try some new ones. They came pre gapped .30 I think, anyway so I have spark, Compression and fuel. Could it be the ECU? Or any electrical component?
Not likely if you have spark and injector pulse. All cylinders are getting both spark injector pulse, correct?

If the distributor is set correctly, I would also lean towards flooded engine.

Remove all spark plugs, remove the fuel pump relay and crank the engine over. That should clear the flood.
 

bEnC10

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I bought a new distributor with cap and rotor with wires and yeah I checked injector pulse so I don’t think it’s the cap. I have the old one still so I’ll slap it on there when I check if I flooded it. Even before when I first tried to start up the engine and barely connected the fuel pump, it still didn’t run. Also when I got the 97 truck to take motor out it came with 2 ECU’s I just took one and left the other one in the body. I was reading somewhere that the 98 trucks came with an anti-theft system. The previous owner might have upgraded their ECU to the 98+ ones and I grabbed it. Preventing me from starting. Kind of a stretch but I’m desperate
 

HotrodZ06

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I bought a new distributor with cap and rotor with wires and yeah I checked injector pulse so I don’t think it’s the cap. I have the old one still so I’ll slap it on there when I check if I flooded it. Even before when I first tried to start up the engine and barely connected the fuel pump, it still didn’t run. Also when I got the 97 truck to take motor out it came with 2 ECU’s I just took one and left the other one in the body. I was reading somewhere that the 98 trucks came with an anti-theft system. The previous owner might have upgraded their ECU to the 98+ ones and I grabbed it. Preventing me from starting. Kind of a stretch but I’m desperate
Possible I would look at the service numbers on the pcms that should tell you what year it is off of, as far as I know every year had a different service number but could also bleed over if early or late built.
 

bEnC10

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Ok so I spark tested and I do have spark to the spark plugs. My ECU is off of a 97 truck so I don’t have to worry about ECU. Guys honestly I’m at a loss, I feel like giving up. I don’t know what else it can be. Im going to take it to tune the ECU at a shop to see if it is actually the ECU. But not any time soon.
 

HotrodZ06

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Have you checked fuel pressure? If its not high enough it could cause a no start.
 

bEnC10

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Yeah I put the key in ACC and the fuel pressure jumped to 60~62 psi. While cranking, was getting ~58 psi but it never dropped below 55. Now when I clicked to ACC and left it there for about 5 min and the pressure slowly dropped from ~59 psi to 50 psi then kept dropping slow. I put a new fuel pump with AN lines with a return. Both lines are -AN6 and the breather for the tank is a an 5/16th? Hose with a lil filter on the end. (If this matters).
 

stutaeng

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Yeah I put the key in ACC and the fuel pressure jumped to 60~62 psi. While cranking, was getting ~58 psi but it never dropped below 55. Now when I clicked to ACC and left it there for about 5 min and the pressure slowly dropped from ~59 psi to 50 psi then kept dropping slow. I put a new fuel pump with AN lines with a return. Both lines are -AN6 and the breather for the tank is a an 5/16th? Hose with a lil filter on the end. (If this matters).
That sounds kinda normal. The pressure should hold 1-2 psi for about 10 minutes.

Regardless, you have enough pressure to start the engine.

I don't have any more advice though. :-(
 
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