01 silverado fires but won't stay running

scipiothompson · March 4, 2018

Hello all. I have a 2001 silverado 1500 4.8l with 195ish on it. I recently took it off the road and didn't touch it for a couple weeks. I went to start it yesterday and the battery was low but it did crank, the engine would fire but wouldn't stay running for more than a couple seconds. Prior to taking it off the road it always started and ran perfectly. Do you think the low battery could be the cause or has it developed a gremlin from sitting for a couple weeks?

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scipiothompson · March 4, 2018

Here we go. Put the charger on the battery for about 3hrs and she cranks better but still won't run for more that a second or two. No dome lights or headlights. From what I've been able to find it sounds like a passlock issue.

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Doug_Scott · March 4, 2018

The fact that the dome light does not work, yet the battery can crank the engine over is simply not logical. On every vehicle I have either owned, borrowed, worked on, or was a passenger in exhibited the following behaviour.

Open door, interior light comes on.

Key in ignition, turn to start, interior light dims slightly, and engine cranks over. If there was a low battery, interior light still came on, and when key turned to start, dome light may go out completely and engine would not turn over, or would crank too slow to start. If the dome light did not come on when door opened, the engine would not make a sound when key is turned to start.

Disconnect both battery cables and clean them. Do not assume that since they look clean that they must be. Also check where the wire enters the terminal on the battery cables. Not uncommon for it to corrode under the insulation at the terminal. Depending on the cables, you may find white powdery stuff at the wire-terminal connection. The problem is going to be something very simple, and once located you will wonder why you didn't notice right away. Simply sitting for 2 weeks will not create some complex issue. Stick to the free things until you exhaust those things. Fix the dome light first.

Justin101714 · March 4, 2018

I’d check the mass airflow sensor for debris. Seems like it’s dying because of airflow issues. Change the air filter too

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muddkatt · March 4, 2018

Low battery along with alternator not charging COULD be the problem. See if it will stay running with jumper cables attached from another vehicle. If that makes no difference, check fuel pressure, should be at least 50PSI. The 01's have an inline fuel filter on the frame. Change it if low fuel pressure is observed. Replace with either a Delco, Wix, or Napa Gold. Do NOT use a Fram or store brand filter from Auto Zone, Oreilly's etc.

If fuel pressure remains low, will need a fuel pump. Highly recommend a Delco pump unless you like saving 20 bucks and changing fuel pumps often.

scipiothompson · March 4, 2018

Low battery along with alternator not charging COULD be the problem. See if it will stay running with jumper cables attached from another vehicle. If that makes no difference, check fuel pressure, should be at least 50PSI. The 01's have an inline fuel filter on the frame. Change it if low fuel pressure is observed. Replace with either a Delco, Wix, or Napa Gold. Do NOT use a Fram or store brand filter from Auto Zone, Oreilly's etc.

If fuel pressure remains low, will need a fuel pump. Highly recommend a Delco pump unless you like saving 20 bucks and changing fuel pumps often.

I'm going to hook the battery charger up shortly and let it cook while I run some errands. I'm hoping to get it running again without spending much time and money on it because the next place it gets parked is out front with a for sale sign.

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Doug_Scott · March 4, 2018

You don't mention location/weather, so I will assume it is winter and cold. How long was "couple of weeks"? 14 days should not create any issues, but, 12-16 weeks can. Did it go through a season change while parked? Was the truck parked in a garage or driveway? When it starts, can you rev the engine up or does it simply appear to start but quits as soon as you release the key? Something you may want to try is slowly release the key until the starter stops and see if it stays running with the ignition between start and run. Depending on your location, mice can do wonders with wiring.

Generally if the battery is strong enough to crank and fire it is plenty strong enough to power the engine to run. While cranking the battery voltage is lower than once it starts running. Even without an alternator.

scipiothompson · March 4, 2018

You don't mention location/weather, so I will assume it is winter and cold. How long was "couple of weeks"? 14 days should not create any issues, but, 12-16 weeks can. Did it go through a season change while parked? Was the truck parked in a garage or driveway? When it starts, can you rev the engine up or does it simply appear to start but quits as soon as you release the key? Something you may want to try is slowly release the key until the starter stops and see if it stays running with the ignition between start and run. Depending on your location, mice can do wonders with wiring.
Generally if the battery is strong enough to crank and fire it is plenty strong enough to power the engine to run. While cranking the battery voltage is lower than once it starts running. Even without an alternator.

Upstate NY, it was parked in 20 degree or less weather and has seen a few days near 50. Outside in the driveway. Second week of February was the last time it was driven or started. If I try to start it with any throttle at all it won't start.

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scipiothompson · March 4, 2018

Upstate NY, it was parked in 20 degree or less weather and has seen a few days near 50. Outside in the driveway. Second week of February was the last time it was driven or started. If I try to start it with any throttle at all it won't start.

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The battery is low enough that the dome lights don't come on and no door chimes with key in ignition. IIRC it had a feature that disables everything other than the ignition if the battery is low.

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Kenrbass · March 4, 2018

oil pressure sensor or wiring to it. The ecm gives it a shot of fuel with a pulse of the fuel pump relay when it first starts. The oil pressure switch is a safety thing. If you get in a crash and loose oil pressure, the fuel pump will cut off. Anyway if the oil pressure switch is not showing pressure, it will not hold the fuel pump on. Most of those have two oil pressure switches. One for the manual guage and one for the ecm. Make sure you get the right one.