intermittent discharge

Asked by Jan 28, 2016 at 12:51 AM about the 1996 Ford F-150

Question type: Maintenance & Repair

Recently i started to suspect my starter was going out acting like it's got a dead spot etc. Then on a 2 hour trip to des moines the other day i noticed i was only showing about a 10 A charge (wipers were struggling etc) but then a little bit later it came back full charge. And then the same thing happened a couple more times. On the way back out of town we happened to stop at autozone for something unrelated to any of this but when we left the starter wouldnt get past the dead spot (guessing). So went in and borrowed a hammer and it started after i tapped the starter but i observed a good size spark at the solenoid connection that seemed to 'spread' almost in slow motion causing the bakelite (?) cap to glow a real nice rose color (!) We did make it 2 hours back but the charge/discharge cycle happened about 3 more times along the way. I live out in the basic middle of nowhere, dont know many folks around here yet but do have a line on a auto electrics guy who's supposed to be back from vacation monday but not much $ to throw around. Any thoughts?

66 Answers


Obvious place to start would be to take the starter down and have it checked. If there are two wires connected on the big post, one of those is tied into the alternator system. It may be that just the solenoid would need replacing, depending on the condition of the rest of the starter.

Appreciate the quick response rowefast. My jack is shot i discovered yesterday so not able to even get it off etc. I did talk to another shop earlier today that suggested a ground issue and i did indeed find that my main battery grnd to eng block was way loose so im encouraged on that score but after tightening it the truck wont turn over. Im getting a good solid single click up top (solonoid/volt reg?) when i try to start. However my charge gage is sitting at about 10A when i energize the system. Im going to hit a neighbor up for a jump when he gets home later and see.


Ya, that is a volt gauge and it should read at l2 volts when you turn the key to on. Not start, but on position. If you have a digital multi-meter, a fully charged battery should read 12.5 to 12.7 volts.

My digital meter reads 12.39 across the battery and a jump from the neighbor produced the same single solid click on top w/ no peep out of the starter. If i can get the starter off today is there a test i can do to isolate starter vs solonoid issue? thanks


Try jumping the solenoid relay bolted to the fender well, near the battery, (for a second only) and see if the starter turns the engine to start. If it does, change the relay. It's a real inexpensive part.

Is that the same as bypassing it? and how is that done?


Yes, it's bypassing it. Use only one of ur jumper cables,. Just connect red jumper cable to ur battery and momentary connect the ither end if the red jumper cable to the relay cabke that goes to the starter. If it cranks, replace relay, if it doesn't, u have an issue with tbe starter


Make sure ur battery is fully charged because having a loose connection on the ground that u found, drained ur battery and could not charge due to the loose ground connection

Hey thanks friend ... so my battery right now is reading 12.39 ... which from what im reading and hearing is abit low but is that too low for this test?


Hey guys, he had sparks flying around the solenoid, why keep trying to put voltage to it when there was a obvious problem down at the starter? Take the starter out and check it over.

I gave the bypass a shot with no response from the starter so i'll get the starter off and then what would be next step to determine starter vs solenoid? thanks again for your help and time


Well this is back yard mechanics if you can't get the starter somewhere to be tested. Have a fully charged batter to hook some jumper cables on to. Take the positive lead and hook it onto the top large post of the solenoid on the starter. Then you take the negative battery cable and hook that up on the flange, (mounting surface) of the starter.Then you hang on to it good, in a bench vice or by hand, & jump with a screwdriver across the top post of starter solenoid to the small terminal on the solenoid. Make sure connections are good. The starter should engage and spin if it is working. If not take the cables off the starter, hook the positive onto the bottom large post on the starter, and when you attach the neg, back up to the flange, it should take off and spin only. The solenoid on the starter is what throws the starter drive to engage into the flywheel (flex plate).

well sounds like something i can handle so i'll give it a shot as soon as i can get my neighbor's jack over here ... wish we hadnt got all that snow and now its all muddy round here dontchaknow!


Make sure to check the positive cable going to ur starter, it may be intermittently grounding or could be partially cut or corrouded, causing starter and spark issues

That would be the one coming from the relay up top?



ok ... waiting on the jack now ... thanks

A couple folks said i could do a test without removing it so i got it jacked up enough to get at it (barely) and with ignition in 'on' position bridged the top positive solenoid post to the starter body with a screw driver. Got a good spark and heard the fuel pump cycle but got no other response. I should add that the inside of the insulator cap was cooked pretty good on the lower post side. And im not 'sure' since i couldnt see it directly but from what it felt like to my fingers there seemed to be a fairly thick wire coming off that lower post that didnt seem to go anywhere and actually felt like the short stub of a really cooked wire.


I do believe you are looking at the problem area.


But you jumping from that post to the starter housing is a direct short. Thats why you saw all kinds of sparks.


Well, there's ur problem. Remove starter to inspect might have a melted connector and replace cable going from relay on fender wall to the starter. Sounds like the cable is cut and grounds when u try to start it, causing the sparks that ur seeing


Hello, said all that in the beginning...very first post..

I appoligize too that i cant stream youtube stuff because of poor signal out here in the boonies so i cant get a clearer *picture* of whats what and where etc so really appreciate eveyones time and input. So about the wire on that bottom post ... wheres it going and/or coming from?


The bottom post wire is from the winding's inside of the starter. When the solenoid gets activated that wire has full juice going threw it to make the starter rotate, work.

Best Answer Mark helpful

Ah .. ok ... so for sure then the motors shot i take it 'and' possibly (?) solenoid as well? Or still an issue of getting them off and tested in a shop? And lets say one or the other is still 'good'. How good is good and should both be replaced anyway? Sorry if these are no brainer questions.


I suggest teplacing them both and get it over with

Yea sounds right ... thanks


Right. replace them both, Starter and the relay on the fender wall since you are out in the boonies.

Ah .. yea ok ... will do ... thanks

Got my Amazon acdelco reman today. .. it went in just fine and fired right up. .. now I can get to town to get the cat's dry food tomorrow and back to church Saturday .. thanks all


Good to hear! Happy travels!

Dept of spoketoosoon. .. yea well. . so Friday I go run some errands/shopping etc (bout 25 miles out) everything seemed fine and first thing I notice on way out of town heading back my transmission shifting hard (volt gage down around 10 again too) and then seeming like it wouldn't shift right. .. trouble making hills and so forth. After a bit felt like I was barely going to make it home even hearing what sounded like small backfire pulling hills. Only once did it pull out of it nearing top of a hill but gage stayed put? A minute later it's back barely pulling. Gage never came back. I get home pull in the drive and put it in park and it's acting like it's gonna die. .. rev it a bit and runs real rough so I shut it down. Didn't fool with it yesterday but this morning it starts like a champ gage is right so I go for short drive, 5mi and on way back gage drops to 10 and then maybe 30 sec it fairly slowly 'sweeps' back up then a moment or two it 'drops' back down. Stayed down till I got home but did run some hills and it pulled fine and no backfire. At home shut it off and restarted just fine but gage was still down. That's my story and I'm stickin to it. ;)


Ok so the starter works, now there is a charging problem hey? Does it seem like the engine is holding back like the catalytic converter being plugged? And you just happen to catch me here on this Sunday, But I'm here anyway.

I already know I need a pro with test equipment just thought you all would get a kick out of my tale-o-woe.


Ya but don't like to see you still having some sorts of troubles. This is sounding electrical and alternator related. Just for the heck of it follow the wires from the alternator to see if you come across any bad wiring. You have some sort of draw on the system, either bad wiring somewhere, or the alternator is bad.

Hey there rowefast . .. don't know what a plugged cat acts like but did feel like eng was holding back yup. And not seeing anything fishy with the alt and solenoid wires. Large alt 3way clip looks real good and clean inside. The small clip I can't seem to disengage but the wire looks good going in and seems to be tight in the clip. The big bolt on I guess power lead 'looks' good and tight. Nothing burnt or overheated looking at solenoid. Anything I can do with my meter?


Well I was going to suggest checking the voltage at the battery but your gauge inside shows a draw. so we know that. Answer me this, when the motor bogs down is that when the gauge is showing the 10 volts? And when the motor starts to pick up does the gauge show normal?

Just started it up and gage is right.


So how did the motor run good I suppose, what I am asking is how fast is the motor running when the gauge goes to 10?

S'funny I did have charge system check at parts store before winter set in and got an all good. Guy even said battery was awesome as old as it is right at 5yr. ... ok been purring right along 6-7 min now and gage just slipped down to about 10-11.

Other than the other day when I got home and it was idling rough it doesn't seem to affect it. Still purring right now.

Normal idle


Ok, here is what I think is going on, I do believe your alternator is giving you grief. It sounds like it is not charging all the time and when it quits charging you are running off of just the battery until it gets run down, then the motor wants to quit running. You can verify with your meter by putting it across the battery when the engine is running and check DCV. It should be at 14.5DCV.

Yea when I'm at speed there's noticeable power drain when gage drops and boost when it comes back full charge except for that one time Friday when it got that boost up a hill but gage stayed down?

Meter reading 11.9, gage I still down and net's got a little 'lope' to idle now


I am not so sure the catalytic converter isn't plugged. You can check this also when it is dark outside, have engine warmed up, take it for a ride, get it hot, when she bogs down stop and look underneath the car at the cat. If it is showing signs of being plugged it will be glowing orange. But check the voltage at the battery when idling, it should be 14.5 DCV.


What are the rpm's at the 11.9 V.?

Yup eng even feels sluggish to trying rev it

No tach

Idle seems definitely down a notch though on top of the looping. Will do on the cat check.


Look at the catalytic converter to see if it is glowing orange. It may be faint in color.


Can't see any glow from cat

Mileage on it is only 109xxx


Ok, rev it up a few times keep checking the cat. Turn the vehicle off after awhile or when she dies, and check the battery voltage. See what it is at (DCV) I have to take my dog for a walk, I'll be back in about 1/2 hr.

Serious power drop now. .. would be real hard to pull a hill. Whoops just as I'm writing that power comes back with gage up blower/heat all back. .. idle up and steady

Took a 10 mile drive. .. gage stayed up whole way. . Cat still not showing any glow but I'll try again after dark. .. DCV at battery was 13.4 before I left and 14.1 when I got back and gage was a smidge higher too.


Ok...why...Well, I am still thinking it is in the alternator. If is was a short of some sort, you would be blowing fuses somewhere. The draw is coming when the alternator is not putting out. All the electrical systems then run just off the battery. It almost sounds like the brushes in the alternator are gone making an intermittent connection. How old is the alternator and the battery?

Battery is 5 ... no idea about alt though knowing history of truck. .. stored in shed for a good while, low mi ... interior hardly sat in etc.. Could be original?


I got to know if the motor starts idling down from normal when the volt meter reads 10 or 11 volts.


Just waiting on ya,

Yea it did seem to drop


Ok then, all the info you have given me, this is what I think at this point...First on the list is the battery. I think it may have a short in one of the cells. I had all this happen to me one time, and it was a bad battery, shorted out, didn't want to run until I changed it. Second would be the alternator. I am second guessing that at the moment because it won't charge properly if the battery is shorting out. Never the less I would suggest if you can to get the battery tested, But really you have 5 yr. on it so it wouldn't hurt to get a new one. The battery could cause the alternator to be acting the way it is...Also, just keep an eye on the cat to see if it glows.

I did have the charge system checked before winter set in at the parts store. They found no issues ... even very surprised battery was 5yo based on its cranking amps

I can get a hydrometer easy enough and check each cell though. Thanks again brother


Battery can have cranking amps but still have a short. Sound good on the hydrometer, I'll check in tomorrow, gotta go watch the Super Bowl! Bronco's and Panthers,

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