Bought A '98 Yukon 5.7..

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Cwhite7089

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Okay so Im new here as of today. about 3 weeks ago I bought a 1998 GMC Yukon automatic 5.7
I love these vehicles but wasnt being picky. Long story short I needed a vehicle and stuck to vehicles I liked, didnt have much cash. Cant finance because 21 with no credit history. You get the idea. I found this gold/tan '98 for $1200 just 30 minutes from me. Only had to bypass the AC compressor to get it home (kept snapping belts). Bought it for 950. I knew for the price it would need work. 233,000 miles and 21 years old, but there are currently 2 big issues:

Saturday the 31st, I drove it to Subway down the road about a mile and a quarter, and noticed for the first time that casually acceleration between 40 and 45mph, it would jerk and shake badly before going into 3rd gear. Possibly the filter and oil, transmission itself, solenoid(s), or torque converters, but Im not sure and cant really be putting money into ALL of those plus other stuff. I make 1600 a month, have obligations each month, and still need a ride. Im hoping to be the one to get it running again but also need to take care of that as soon as possible.

Second issue is that just last Friday, I went to start it up and take it around the block, wouldnt start. No lights, no turn over, not even ticking. The chime for the door being open was dying and there was a whining sound from the same area. Before it all stopped completely. Had the battery charged from 7.5 volts to 12. It held the charge for 4 days till today i put it back in (working through the entirety of daylight hours previously). But still nothing. The ground seems okay, the connections on the battery are good except for the negative terminal connection (side mount) is slightly loose but on there correctly and connected firmly to the bolt, so it should start, right? The fuses under the hood all look good. I cant currently get to the fuse box under the dash or look at the starter. But all other things seem alright. Anyone else ever dealt with a similar situation with the battery? The motor runs good but could use a tune up. On the way home, the shifting was just slightly jerky and wrote it off as age and wear and tear. I mean there is no handle on the inside for the front passenger door and the dash has chunks missing up top and trim splitting off around the stereo and AC controls, so definitely seen better days.
I know I could have saved up for a better one but I do not regret it. Just gotta figure it out

Any input would be greatly appreciated, thank you!
 

east302

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I’d put the battery cable issue at the top of the list as that can cause all sorts of system headaches.

Check the alternator output to rule that out as the cause of the dead battery. It should be putting out around 14V at idle - measure from the alternator cable post to the battery negative. Repeat by measuring voltage at idle between the two battery posts. The difference between the alternator and battery voltage should be very low...say 0.1V or less. If it’s much more, there’s an issue with the cable between the battery/alternator and/or the connection at the battery. YouTube has plenty of “how to” videos in case you aren’t familiar with it.


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Cwhite7089

Cwhite7089

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I’d put the battery cable issue at the top of the list as that can cause all sorts of system headaches.

Check the alternator output to rule that out as the cause of the dead battery. It should be putting out around 14V at idle - measure from the alternator cable post to the battery negative. Repeat by measuring voltage at idle between the two battery posts. The difference between the alternator and battery voltage should be very low...say 0.1V or less. If it’s much more, there’s an issue with the cable between the battery/alternator and/or the connection at the battery. YouTube has plenty of “how to” videos in case you aren’t familiar with it.


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Thank you but the issue is that I cannot test at idle. As stated, it will not start. I dont get anything. No lights, no sound, no gauge fluctuations, nothing. as if there isnt a battery there. Kinda hard to start test at idle haha

Put a battery charger to it for 40 minutes and same results
 

east302

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Yeah...that was a bit of a brain fart on my end!

What is your battery voltage measured at the cable bolts?

On your loose ground connection, are the cable’s terminal bolt threads stripped? Those just pop out and can be replaced for a couple of bucks.




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Cwhite7089

Cwhite7089

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Yeah...that was a bit of a brain fart on my end!

What is your battery voltage measured at the cable bolts?

On your loose ground connection, are the cable’s terminal bolt threads stripped? Those just pop out and can be replaced for a couple of bucks.




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I dont know for sure what the issue is obviously but I am starting to believe its a loose ground or connection somewhere. The negative terminal has the loose connection to the cable but barely loose at all, as in it doesnt move, just a slight wobble (very slight). Going to put a washer there anyways. No stripping noticeable
 
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Cwhite7089

Cwhite7089

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Yeah...that was a bit of a brain fart on my end!

What is your battery voltage measured at the cable bolts?

On your loose ground connection, are the cable’s terminal bolt threads stripped? Those just pop out and can be replaced for a couple of bucks.




Sent from my iPhone using Tapatalk


I dont know for sure what the issue is obviously but I am starting to believe its a loose ground or connection somewhere. The negative terminal has the loose connection to the cable but barely loose at all, as in it doesnt move, just a slight wobble (very slight). Going to put a washer there anyways. No stripping noticeable
 

BennyR72

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Sorry if I'm stating the obvious, but have you checked the actual battery? Just cause you can get it to 12V on a recharge doesn't mean that it's able to hold that charge or that its got the CCA left to start the truck. Have you tried jumping it off a battery that you know is good?

If the alternator is doing its job, you'll have no problem driving around while the alternator is putting out power and you'll probably even be fine for short stints where the truck isn't running and you can still start it back up, but if the battery is toast then that's not gonna last for long and you'll be having the same problems. Remember that starting the truck is putting the biggest strain on your battery so even though you might have charged it to 12V, the strain of the starter is eating up a ton of power. Try charging as high as you can get it, then starting with a multimeter attached and seeing where your voltage drops to during and after you try to crank it. If your voltage is way down, that's a pretty good indicator that your issue is a battery issue, not wiring.

I'd say it's unlikely that its a bad ground causing all the havoc (other than just being a contributor to a draw somewhere), if it was the main cause, you'd probably see a stall when you were driving and the ground shorted out. You've probably got a mixture of a bad alternator, bad battery, and parasitic drain somewhere.

As for the shaking: Did you only notice it when the truck tried to drop into 3rd or was it at a specific RPM regardless of gear? Too little info to really try and diagnose, but I'd say that you can definitely rule out the need for oil or a oil filter as a cause (though they're probably things worth doing anyway if you're gonna try and squeeze some more miles out of that motor).
 
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MeNmyHoe

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On many of these Tahoe's, there is a mega fuse located just to the left of the radiator. If you follow the cable it runs to the fuse block. Check that megafuse and make sure that it is not blown. If it is good, then check the fuses in the block. If those are good, pick up a cheap remote starter button and connect that directly to the starter to bypass the ignition switch. Also, and this may sound like a dumb question, but have you wiggled the battery cables to check for intermittent connection? It is possible that the cable ends are just worn out. Also, with the age and mileage of the truck it is not out of the question to have internally corroded cables. Food for thought...
 

BennyR72

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On many of these Tahoe's, there is a mega fuse located just to the left of the radiator. If you follow the cable it runs to the fuse block. Check that megafuse and make sure that it is not blown. If it is good, then check the fuses in the block. If those are good, pick up a cheap remote starter button and connect that directly to the starter to bypass the ignition switch. Also, and this may sound like a dumb question, but have you wiggled the battery cables to check for intermittent connection? It is possible that the cable ends are just worn out. Also, with the age and mileage of the truck it is not out of the question to have internally corroded cables. Food for thought...
I think you're talking about the fusible link. That could be a cause of the vehicle simply not starting and everything being dead, but wouldn't be the cause of symptoms common to a severely drained battery (ie. dim lights, chime whine, no starter response, etc.) The fusible link (like all fuses) either completes the flow of power, or stops it entirely. Cwhite said that when he tried to start it everything was dead but there was a door chime whine If the fusible link was blown, everything would be dead as it's that line that delivers power to the main fuse box - which in turn feeds everything else.

I said it before, but I'll say it again: Everything about these power issues screams bad battery, which incidentally is about the easiest thing to test. Keep it simple until you've got a reason to look deeper.

If you just have to make it more complicated (or the battery actually tests fine),there's a few things to look at instead of just poking around wildly:

The starter runs off a relay not a fuse and that relay is located under the hood in the main fuse box at the top left (passenger/firewall). Pull it out and see if it's corroded or if anything looks melted or loose. It's a cheap (<$5) part to replace and they do go bad every once in a while, especially if you've got moisture in there.

Next you can look at the ECM-B fuse. Same under hood fuse block, but this time it's actually a fuse. It's a 20A mini that's located in the first column of the mini fuses, first one on the top. These have been known to cause all sorts of starting issues, but as far as I know you'll still get a crank but nothing will fire. Again, cheap (SUPER CHEAP) fix if that's the problem. While you're under there you can check the IGN-E fuse which is in the same column and is the third down from the top. Again, this usually will still crank the engine even if it's blown but you won't get a spark. But hell, we're pulling fuses anyway so might as well, right? And since we're onto ignition fuses now, might as well check the door panel ignition fuse. Top right corner of the fuse box on the drivers side behind the door.

Remember that there's hundreds of different wires running throughout your vehicle, so its always easiest and best to start by isolating the problem. If everything is dead - or dying - the chances that every single fuse in your vehicle is blown is pretty slim to non, especially considering that you had it driving last week. Chances are that if everything is dying, there's an issue with the source, THE BATTERY. Just cause the starter isn't cranking doesn't mean its a starter issue; the starter needs a ton of amperage to do it's job.
 

MeNmyHoe

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I missed the part about the door chime getting faint then stopping completely.
 

BennyR72

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I missed the part about the door chime getting faint then stopping completely.
No sweat, it’s good to see that folks are still interested in trying help either way; this forum has gotten kind of cold recently.

I just keep screaming battery cause this guy said he doesn’t have a lot of money or time to spend, but it seems like he’s trying to find the most difficult solution instead of the easiest.
 

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