Okay... so after a run of problems that I've solved, I'm running into another that I'm having the hardest time diagnosing.
Usually (I've had the truck 10 years now), I turn the key, the starter turns the motor over vigorously (RPMs go to 1100 or so), and then they drop back to 900-1000, until the engine warms up at which point the RPMs have lowered to 600 or so.
Recently, the sequence goes like this: Turn key, engine turns over easily, RPMs go to 1100, drop to 400, rise to about 800, and then the engine stalls. Try again, and it just doesn't even try to stay started, unless I give it some gas right after releasing the key to keep the motor spinning. Once started, it drives like a dream though.
If it's not a totally cold start (i.e. less than about 4-5 hours after last running), it starts like normal.
Recent maintenance history (I figure some of this has some bearing on all of this):
Sometime before Memorial Day, my water pump bearings and/or belt tensioner got enough play in them so that the serpentine belt ended up jumping a groove or two, to eventually throwing/destroying the belt on the Friday prior to Memorial Day.
Over that weekend, I got the water pump and belt replaced. Everything seemed fine for about a week, until I started getting heinous belt squeal on cold starts. Turns out that the belt tensioner had some kind of gasket or shim between the two halves that had cracked and partially fallen out, making the two halves of the tensioner no longer parallel, and causing the belt to be misaligned. I replaced the tensioner- squeal solved.
About a week after that, I was preoccupied at work and locked my keys in the truck with the ignition turned to "ON", but not with the engine started. Ran the battery down, needed a jump. After that, for the next week, it struggled to turn the starter hard enough to actually start the engine, and it gradually got worse. Since it was a 5 year old battery in Texas, I replaced it under warranty, and now it turns over like a champ, but does that weird business I describe at the top of the post- it turns over vigorously and sounds like it fires up, but it doesn't stay started well.
Fuel pump comes to mind, but wouldn't that be an issue while driving? Alternator also comes to mind, but everything's bright and the battery seems to be charging fine - I've driven on it for a week now with no problems other than this starting business.
Any ideas?
Usually (I've had the truck 10 years now), I turn the key, the starter turns the motor over vigorously (RPMs go to 1100 or so), and then they drop back to 900-1000, until the engine warms up at which point the RPMs have lowered to 600 or so.
Recently, the sequence goes like this: Turn key, engine turns over easily, RPMs go to 1100, drop to 400, rise to about 800, and then the engine stalls. Try again, and it just doesn't even try to stay started, unless I give it some gas right after releasing the key to keep the motor spinning. Once started, it drives like a dream though.
If it's not a totally cold start (i.e. less than about 4-5 hours after last running), it starts like normal.
Recent maintenance history (I figure some of this has some bearing on all of this):
Sometime before Memorial Day, my water pump bearings and/or belt tensioner got enough play in them so that the serpentine belt ended up jumping a groove or two, to eventually throwing/destroying the belt on the Friday prior to Memorial Day.
Over that weekend, I got the water pump and belt replaced. Everything seemed fine for about a week, until I started getting heinous belt squeal on cold starts. Turns out that the belt tensioner had some kind of gasket or shim between the two halves that had cracked and partially fallen out, making the two halves of the tensioner no longer parallel, and causing the belt to be misaligned. I replaced the tensioner- squeal solved.
About a week after that, I was preoccupied at work and locked my keys in the truck with the ignition turned to "ON", but not with the engine started. Ran the battery down, needed a jump. After that, for the next week, it struggled to turn the starter hard enough to actually start the engine, and it gradually got worse. Since it was a 5 year old battery in Texas, I replaced it under warranty, and now it turns over like a champ, but does that weird business I describe at the top of the post- it turns over vigorously and sounds like it fires up, but it doesn't stay started well.
Fuel pump comes to mind, but wouldn't that be an issue while driving? Alternator also comes to mind, but everything's bright and the battery seems to be charging fine - I've driven on it for a week now with no problems other than this starting business.
Any ideas?
