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We need vehicle info.

If you still have the fuel pressure gauge monitor the fuel pressure while starting. Tell us the pressure when it starts and dies.

Do you have a meter? Monitor the ignition voltage while it cranks and fires. Make sure the voltage is good when it fires and it's still good after it dies. If not the ignition switch or relay could be bad.

We need vehicle info to know how to help you.

Ted
 

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We need vehicle info.

If you still have the fuel pressure gauge monitor the fuel pressure while starting. Tell us the pressure when it starts and dies.

Do you have a meter? Monitor the ignition voltage while it cranks and fires. Make sure the voltage is good when it fires and it's still good after it dies. If not the ignition switch or relay could be bad.

We need vehicle info to know how to help you.

Ted
1998 k1500 5.7 liter
 

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We need vehicle info.

If you still have the fuel pressure gauge monitor the fuel pressure while starting. Tell us the pressure when it starts and dies.

Do you have a meter? Monitor the ignition voltage while it cranks and fires. Make sure the voltage is good when it fires and it's still good after it dies. If not the ignition switch or relay could be bad.

We need vehicle info to know how to help you.

Ted
Relay isn't bad. We changed it and then switched it out with mine (1997 Tahoe) and it worked fine. Just changed the ignition switch because we too thought this was the issue.
 

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Thanks for the truck info.

So you have ignition voltage at the distributor while starting and after it dies? In other words you have ignition voltage with the key in "run"?

Ted
 
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If you replace parts just for the heck of it without knowing the part you replaced was bad you can introduce other problems. Don't get me wrong - substitution with a known good part is good troubleshooting. But today more and more parts are found to be bad new out of the box.

Ted
 
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See if it runs on an alternative fuel source, that should be a simple test and enough to convince you to dig a little deeper into the 50psi output. Maybe your pump is good...maybe it just has a faulty ground, or lack of a good lead from somewhere...does the relay get warm quickly? (not because its bad...it could be a sign of poor connection... Poor connections want to draw more amps to bridge the gap a side effect of this is heat) It would behoove you to heed all above advice, as these folks are spot on for the info provided...it is very hard to move past 50psi when that is at least 10 lbs to little and start and die is a well known symptom of low fuel pressure.
 

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You could try propane in a vac line or the pcv breather or take off the air filter and see if you can keep it running with brake clean (the flammable kind). Carb clean works also. Be careful of the mass bars...they don't deal with direct pressure well, and creating a lean condition can be dangerous... Ie, fire... This will also help us move away from a fuel issue if you happen to disproved it, and we can move on to other things...
 

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Tested the fuel pressure at the intake, started at 50 and dropped quickly. Tested the pressure coming directly from the pump, 65 psi. That eliminates the pump as the issue. Pulled the intake cover back off and checked each injector, got no fuel from 3. This was a set we got off of a friend's truck who said they worked great before the wreck. Ordered a new set, which will be in Saturday. I'll update when I know more.
 

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When You replaced the spider did you get an oe style with poppet valves or the upgraded one with electronically controlled injectors? If you got the poppet style you may actually be losing fuel pressure at the fpr, I would check that. The loss of fuel pressure would keep the poppet valves from opening.
 

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Sam if you have a vacuum line going to the regulator you can remove it and the fuel pressure should go to the max pressure of the fuel pump. If however it doesn't have a vacuum line you'll have to do the below to test for max pressure.

If your FPR is a bypass type with a return line to the tank and no vacuum line: If it does have a return line if you clamp the hose part of the return line with a pair of vise grips. That will force the pressure to max to the fuel rails. If you keep the gauge on the output of the FPR you will see it go to 65 psi. The truck should start and run. Don't leave the return line clamped off.

You may have installed the wrong FPR or it was bad out of the box.

Ted
 

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I replaced a fuel pressure regulator in a 1998 Chevy 3500 with 350 engine 5.7. While I had the throttle body off and access to the manifold I cleaned it because it was really gunked up. I used degreaser letting it sit overnight and then the next day sprayed mineral spirits on it and wiped it clean and sprayed with air hose. When I got everything back together it didn't want to start as easy unless you pressed gas peddle. It backfired from tail pipe. So I let it sit overnight and the next day tried again and it cranked with a really rough idle. So I replaced the MAP sensor and no change. I still get a error code of P0108 which is manifold absolute pressure circuit high input. Here is a link to a video of what it is doing: https://photos.app.goo.gl/DH4MozQRYENANMwM2

I should also mention that some type of liquid was coming from Cadillac Converter. It was slick and smelled like gas. I assumed it was gas rubbing against carbon buildup and that is why it was slick and smelled that way.

Any ideas as to why it is doing this?

Thanks, Shane
 

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@ Shane Powell
98 should have spider injectors a map and a mass. Test fuel pressure...watch leak down...start see if it jumps or stays steady...make sure both map and mass are plugged in, make sure no air leaks from mass back check vacuum... Report back.
 
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So did we ever figure out the issue? I have a 1998 K1500 5.0 shutting off after 2-3 seconds as well, cant figure it out. Fuel system is new front to back, new ecm installed, getting spark, getting fuel, new mass airflow, new tps, fairly new plug wires, plugs are new.
 
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