Truck won't stay running
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Truck won't stay running
Hello, everyone. Long post ahead... I just wanted to list everything I've tried so far to keep my 1999 Dodge Dakota Sport truck running. I've posted in another forum and have tried a few things but I decided to post my questions in a Dodge-specific forum. I'm not a mechanic by any means but I can do some stuff... But yeah, there's a ton I don't know.
It's a truck that sits. I only use it if I need to move something or do work on my property. I try to remember to start it every month or so. The battery is only about three years old but I have to charge it/jump it when I want to start the truck because it doesn't get much use.
A couple weeks ago, the truck started up, held a decent idle for about a minute and a half and after that, the rpms started to decline until it sputtered out completely. The first couple times it did that, and after it died out, there was NOTHING. No lights on the dash, no dome light, absolutely nothing. I cleaned off the junk from the battery cables and this last time it died, the battery at least had enough to illuminate the dash and headlights and continue to try to start.
Here's what I've done: I went to O'Reilly's and AutoZone to have the battery tested and both reports were good. I have a cheap, old, analog multimeter and it hovered around 12 (ish) volts.
I know it's a bad way to test the alternator but I did the old school trick where I disconnected the battery cable while the truck was running. It stayed running (for a bit, like I said, I only have about a minute long window to work with). Someone suggested another way to check the alternator... Pay attention to the headlights. When the truck sputtered out, if the lights got brighter or stayed the same: bad alternator. If they got dimmer: good alternator. I don't know how consistently accurate that test is but I did it and the lights stayed the same. Thinking it could be Feul related, I unhooked the air intake and sprayed some starter fluid when it started dying down. It didn't do anything (except make some popping noises).
The gas is over a year old. It has about a quarter tank. It might just be bad gas but I figure if it's good enough to initially start it, it should be good enough to keep it running?
A couple more suggestions has been to clean the MAS and MAF (not sure what/where the MAF is) and to check to make sure the exhaust isn't clogged (not sure how to do that either).
IF needed, I can take out the alternator to get it bench tested but the AC lines run along top of it so I don't really see how it comes out without disconnecting them...
There it is. Any suggestions on other things I could try are welcome. Of course, I'm hoping to do what I can without spending much or any $ because it's just a farm truck. Thanks in advance.
It's a truck that sits. I only use it if I need to move something or do work on my property. I try to remember to start it every month or so. The battery is only about three years old but I have to charge it/jump it when I want to start the truck because it doesn't get much use.
A couple weeks ago, the truck started up, held a decent idle for about a minute and a half and after that, the rpms started to decline until it sputtered out completely. The first couple times it did that, and after it died out, there was NOTHING. No lights on the dash, no dome light, absolutely nothing. I cleaned off the junk from the battery cables and this last time it died, the battery at least had enough to illuminate the dash and headlights and continue to try to start.
Here's what I've done: I went to O'Reilly's and AutoZone to have the battery tested and both reports were good. I have a cheap, old, analog multimeter and it hovered around 12 (ish) volts.
I know it's a bad way to test the alternator but I did the old school trick where I disconnected the battery cable while the truck was running. It stayed running (for a bit, like I said, I only have about a minute long window to work with). Someone suggested another way to check the alternator... Pay attention to the headlights. When the truck sputtered out, if the lights got brighter or stayed the same: bad alternator. If they got dimmer: good alternator. I don't know how consistently accurate that test is but I did it and the lights stayed the same. Thinking it could be Feul related, I unhooked the air intake and sprayed some starter fluid when it started dying down. It didn't do anything (except make some popping noises).
The gas is over a year old. It has about a quarter tank. It might just be bad gas but I figure if it's good enough to initially start it, it should be good enough to keep it running?
A couple more suggestions has been to clean the MAS and MAF (not sure what/where the MAF is) and to check to make sure the exhaust isn't clogged (not sure how to do that either).
IF needed, I can take out the alternator to get it bench tested but the AC lines run along top of it so I don't really see how it comes out without disconnecting them...
There it is. Any suggestions on other things I could try are welcome. Of course, I'm hoping to do what I can without spending much or any $ because it's just a farm truck. Thanks in advance.
Last edited by Thejon; Dec 10, 2024 at 04:11 PM. Reason: Clarity
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I'll try that for sure. Thanks!
Should I start it WITH the charger connected and running or start it and THEN hook up the battery charger? Or does it matter?
Should I start it WITH the charger connected and running or start it and THEN hook up the battery charger? Or does it matter?
Last edited by Thejon; Dec 11, 2024 at 09:59 PM.
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I've heard other people say that too.. I always thought, with most vehicles, the battery pretty much just starts it and then the alternator takes over (I'm probably way off). Heck, I remember getting standards started by popping the clutch, even with a dead battery. I guess these truck are different.
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The alternator is likely charging very little at idle. With it running you should have 13.5 to 14.8 volts at the battery terminals. With engine off, battery should be at 12.5 to 12.8 volts. Dodge computers notoriously don't like low voltage, and will start acting weird under 12.5 volts.
The PCM controls the charging rate, pulsing the alternator field to maintain the 13.5-14.8 volts depending on the present load.
It might also be struggling to make the transition from open loop to closed loop. Between old fuel, old oxygen sensors, and a highly likely dirty idle port, I'd find it high likely that it's trying to look at the oxygen sensors to go closed loop, and choking itself lean. See if you can get it to "high idle" using your foot to keep the throttle cracked open around 2,000 RPM, as that will defeat the idle port and make the transition a little easier.
The PCM controls the charging rate, pulsing the alternator field to maintain the 13.5-14.8 volts depending on the present load.
It might also be struggling to make the transition from open loop to closed loop. Between old fuel, old oxygen sensors, and a highly likely dirty idle port, I'd find it high likely that it's trying to look at the oxygen sensors to go closed loop, and choking itself lean. See if you can get it to "high idle" using your foot to keep the throttle cracked open around 2,000 RPM, as that will defeat the idle port and make the transition a little easier.
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Battery also keeps PCM memory alive when it is just sitting, so, the battery will discharge over time.
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I Thought there was something wrong with the battery or I had a parasitic drain but what you said about the pcm makes sense. I started leaving the battery unhooked when the truck was not in use.
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The alternator is likely charging very little at idle. With it running you should have 13.5 to 14.8 volts at the battery terminals. With engine off, battery should be at 12.5 to 12.8 volts. Dodge computers notoriously don't like low voltage, and will start acting weird under 12.5 volts.
The PCM controls the charging rate, pulsing the alternator field to maintain the 13.5-14.8 volts depending on the present load.
It might also be struggling to make the transition from open loop to closed loop. Between old fuel, old oxygen sensors, and a highly likely dirty idle port, I'd find it high likely that it's trying to look at the oxygen sensors to go closed loop, and choking itself lean. See if you can get it to "high idle" using your foot to keep the throttle cracked open around 2,000 RPM, as that will defeat the idle port and make the transition a little easier.
The PCM controls the charging rate, pulsing the alternator field to maintain the 13.5-14.8 volts depending on the present load.
It might also be struggling to make the transition from open loop to closed loop. Between old fuel, old oxygen sensors, and a highly likely dirty idle port, I'd find it high likely that it's trying to look at the oxygen sensors to go closed loop, and choking itself lean. See if you can get it to "high idle" using your foot to keep the throttle cracked open around 2,000 RPM, as that will defeat the idle port and make the transition a little easier.