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Won't keep a charge

3K views 24 replies 9 participants last post by  Astrofarian 
#1 ·
Hello,
This is the first time I've been on this forum so if I have done it wrong I will apologize in advance.

I have a 1993 Chevy Atro AWD that I purchased back in January. This past week it died on me as I was driving it and I could not get it restarted. Someone suggested that it may be the ECM so we had it tested and it was, indeed, junk. Replaced it and had it up and running on Sunday so we took it for a test drive. I was very surprised at how well it ran. Smooth with no hesitation. It ran better than it had since I purchased it. We didn't make it home before I started losing dash lights, then headlights, then everything. We ended up having to have it towed home.

To me it seemed like it was the alternator so we had it tested. While it passed, it was very noisy and didn't turn as freely as it should have so we replaced it. Started it again and it sounded rough this time. For some reason the battery isn't getting any juice from the alternator while running. It will run until the battery is drained and then die again. We had the battery tested and it came back fine. I got some information from this forum and took at look at the fusible links behind the battery and they are all intact (never worked on a car in my life until now) so I'm assuming they are fine. I removed and had tested the new ECM on the off-chance that it was fried again and it passed. I just started the van again and it drained what was left of the battery and died again.

I need this car for transportation and don't have the funds to have it taken somewhere. I need to try and do this on my own.

Is there something else I could look at? Is there a separate fuse/relay for the alternator?

Any information would be greatly appreciated.

Thanks so much.
 
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#2 ·
Start by testing the voltage at the battery when it is running, you should have over 12v going back into the battery, 13.5 -14 is what it should be IIRC.
Give the positive cable from the alt a good looking over, and also consider adding a ground wire from the alt case to where the battery goes to ground on the body. The alt is grounded through its' mounting bolts to the bracket, to the block. Often these connections get greasy and gunked up making the ground connection flakey.
 
#3 ·
+1 on what WoodButcher suggests. Check that voltage while the engine is running.

It sounds like your alternator tests good. Your battery tests good. We're just not getting enough Edison Medicine from the alt to the battery. Inspect and/or upgrade that connection and the ground connection. Look at the "Big 3 Upgrade" sticky in the electrical section.

Be cautious about running the battery down over and over again. That will kill the battery pretty quickly. So after you do whatever you end up doing, you may need to replace the battery anyway. But you have to do what you have to do while testing and repairing.

Good job for you taking on all this after having never worked on a car.. :rockon:

Lump
 
#4 ·
Follow all the cables. Clean the ends with a wire brush. Clean where the grounds attach with a wire brush. Reinstall with a glob of dielectric grease on everything.

Somewhere, something's corroded and/or dirty and isn't making good contact.

Oh, and double-check your serpentine belt and tensioner - if they're not good and tight, the alt won't spin properly to charge the battery.
 
#5 ·
Thanks for all of your help.

Understand that I did not put the alternator in... lol, my boyfriend did. He works full time though and we have nowhere to work on the car at night.

Wanted to add that we also replaced the starter. It was bad and had been acting up for quite some time. Seemed like while everything else was going to hell in a handbasket, we'd might as well take care of that too.

I'm assuming that the radiator shroud will have to be taken off before I can get to the alternator, yes? Now I know that the alternator has a wiring harness, could the place where that clips in be dirty? I tried finding the wires on the alternator yesterday and could not find (with the limited space I had) the wires at all. Should I also check the the wires to the new starter? Someone told me that it could be a bad ECU - you think?
 
#6 ·
Check the small wired plug that plugs into the alternator. They have been known to go bad. It is where the computer sends the signal to the alt to charge.
As for the shroud removal. It is easier to do with it off. I have done it without taking it off and it is a pain that way.
 
#7 ·
I can't remember ever having to remove the upper fan shroud to R&R an alternator. However there is a

nut or bolt in the backside and to get to it (them) youse will have to remove the doghouse (engine cover).

Tools required are; 15mm swivel socket with ratchet, and 2' extension (to make it easier) to get to firewall

fasteners, 10mm socket, ratchet and short extension (to make it easier) and a 7mm nut driver.

Be careful as most of the parts are plastic. Once the doghouse is out of the way, you will need a 10mm

socket, ratchet and a looong arm, or 2' of extension(s) (again to make it easier). Around on the front end

you will want to release the serpentine belt from the tensioner (5/8" short socket and breaker bar) will do

the trick, then remove; the battery negative cable, so youse don't weld anything under the hood, the two

wire connector on top of the alternator, and the wx-proof connection (12 vdc) that is in back of the alternator.

Remove the front bolt(s) holding the alternator on the engine. Installation is reverse of the above.

Good hunting

Uncle Bob
 
#8 ·
Can anyone tell me what this is, and whether or not this could be the culprit? If you are looking at the engine from the inside of the van it plugs in on the right hand side down lower. I took this picture to the auto parts store and they couldn't even tell me what it was never mind whether or not it could be the culprit.
 

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#9 ·
That connector in the photo may be something like the cigarette lighter or the lamp in the glove box. Difficult to tell at that close zoom. If it comes from INSIDE the passenger compartment, like hangs down from the radio area, it's probably something like that. If it comes from the engine compartment, it's probably something else.

If poking around behind the alternator, be very careful of the large, single terminal with the rubber boot. That's hot with 12v power. The two pin connector that ChevyMaher mentions is safe to unplug and plug back on. But if you want to remove the alternator, disconnect the battery first before doing anything with the larger single connector.

Lump
 
#10 ·
janeskid64 said:
Can anyone tell me what this is, and whether or not this could be the culprit? If you are looking at the engine from the inside of the van it plugs in on the right hand side down lower. I took this picture to the auto parts store and they couldn't even tell me what it was never mind whether or not it could be the culprit.
That looks like the detonation sensor plug in the head. That is a Zebra we looking for horses.
 
#11 ·
Okay, well rats!!

This is not inside the passenger compartment - it plugs right into the side of the engine and the plastic around it is broken so it doesn't snap in, it just sits there. I'll try and take a better pic and see what happens.

Thanks guys for your help.
 
#12 ·
As Randy said, it looks like the knock sensor that plugs into the passenger side head. You will need to get a replacement plug and splice it in, either from a parts house or a junkyard.
 
#15 ·
Okay, so we have removed the alternator again and had it tested - it's good. We replaced the plug that goes into the back of the alternator. Friggin thing will start and runs wonderfully, but still not charging. I'm ready to give up. I have to have a running vehicle but I'm out of options here. I don't have the money to take it somewhere and have the issue traced. At this point I"m looking at putting it on craigslist and trying to get it sold and get something else. Don't know what we've missed.
 
#16 ·
First check the basics; is the alternator charging while in car? battery voltage >13V?.

Have a very carefull look at the cabling of alternator and starter, perhaps easiest with the alternator out.

Next, try starting to unplug your fuses you don't strictly need, and eliminate the circuits one by one.

I also had a strange draining issue, and just recently with the subframe and complete wireloom removed due to other work, discovered that the alternator charging cable isolation was worn off at about the location where it splices into the main cable loom. Normally this is quite hard to access, it should be on the left side of the alt when standing in front of the van. In my case, it probably touched the body/alt,. It is very tight under there, so something like this could easily happen.
 
#17 ·
Try connecting negative (black) battery post to alternator housing using a jumper cable, see if battery takes a charge.

Who tested that battery (and the alternator)? How old is the battery? I just had a wrong diagnosis this week on my battery - screwed up half my day - "thanks" Advance Auto Parts!

How long ago was the starter installed? Those starter wires might have been reinstalled incorrectly or bent / twisted on the posts, might be touching the frame and grounding out etc.
 
#18 ·
Thanks so much for the suggestions. As soon as my bf gets back we'll start there. I honestly don't know how old the battery is - it came with the van. It was tested by O'Rielly and they said it was still good. I will have him check with the jumper cables as soon as he gets back.

This is, at best, very frustrating and tiring. I'll also have Tig check the starter wiring as well.

What really stinks is that I honestly don't what came first, the bad ICM or this lack of charging issue. It was just there once we got the van put back together the first time. I have no idea if it was going on when the ICM went out or not - I just wasn't paying attention to any of the gauges at that point. Tig put the starter in after the ICM went out so I should probably have him start there first.

Anyway, thanks again. I'll keep ya'll posted.
 
#19 ·
I just wanted to thank all of you for helping me troubleshoot the electrical issue in my Astro. I told my bf for two weeks that someone here had suggested checking the wires around the starter (because he replaced it) to make sure nothing was out of place or bent. Would he do that.... no! After me finally harping on him, he checked it and imagine what was found? He had not hooked up one of the wires. Once he did that it's been running fine.

Thanks again.
 
#21 ·
The sign of true manhood is not how many drunks you can beat up at the country and western bar. It's if you aren't afraid to re-check your wiring when your girlfriend suggests it. Just think of the prospective man-points he COULD have earned if he'd been able to say "I fixed the van honey. Saved us an 800 dollar trip to the mechanic".

Tell that guy he just got a ding on his man card.

And make him watch a weeks worth of Oprah.

Lump
 
#23 ·
You guys were so helpful the last time I had issues with my van that I'm hoping to find help again this time.

It's the same 1993 Chevy Astro. It died last night again and we haven't been able to get it started. Did many of the things it did last time when it was the ICM. I took that out this morning and had it tested. It passed. Switched out the ECU because I had a spare because of the issues we had last time. Still won't start. It will turn over. I checked to see if it was getting spark and that checked out fine.

No interior or exterior lights although the computerized dash lights all work.

I'm really stuck here. I need this van to get back and forth to work. Help!
 
#24 ·
Seems like it's getting spark.

Next thing in the "Check logical stuff" continuum is FUEL. Is it getting fuel? If you have a throttle body injection (TBI) system, you can remove the air cleaner and manually move the accellerator cable linkage (engine off) and see fuel spraying out of the injectors. They spray straight down into the TBI cups. If you have other kinds of injection, I'm not good on those.

Replacing the fuel filter and testing the fuel pressure is the next logical move. Suspecting the fuel pump is the general idea.

The cheap fuel pressure gauge from Harbor Freight will work with your year van. You may have to rig up a simple adaptor with a short piece of fuel hose. There's also a way to check the VOLUME (not pressure) by disconnecting the fuel filter, turning on the pump for X seconds and measuring the output. But I don't recall the exact procedure. Some suggest it's not as accurate as the PRESSURE measuring method, but in your case (our case) we have low pressure pumps that I think are tested just fine by that method. Newer vans have much higher fuel pressure.

If you DO NOT see fuel coming out of the injectors, or if you disconnect the fuel filter, turn on the pump and do not see fuel coming out of the open line, then first check the fuel pump relay.

FLASH - Remember that disconnected wire thing you showed us earlier - Could that be the connector to the oil pressure fuel pump sensor thing?

Short answer -
Check Spark (done)
Check Fuel (do that next)

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