A ground to ground measurement of any voltage indicates a serious problem somewhere. Any voltage measurement across any connections in line indicate a voltage drop and with 9.5 volts, I would think something would start getting hot. Make sure everything is hooked up right. If so, I’d lean towards an internal alternator issue where something inside the alternator that is supposed to be hot (12 v) is touching something going to ground like the diode block bending and hitting the case or something as drastic as that. This is a pretty strange situation, so I’m sure the final solution will be just as strange.
Did you try what I suggested below?
WATERBOY: YES, I cleaned all cable connectors and battery posts with files. Both batteries, after recharge, check 12+ volts. Disconnecting + battery cable eliminates all voltage reads. Connecting the + cable to solenoid gave 9+ volts with either small wire connector on solenoid post, 0 with both disconnectec. I CLEARLY have a short to ground!!!
I connectected the +voltmeter to the STARTER GROUND post and the -voltmeter to the battery -post and got 0 volts. With either small-wire connector on solenoid +post, I get 9+ volts. Do you accetpt the fact that this means that I have a short to ground which is FIGHTING the +12+ volts fed to solenoid/starter???
No, a ground to ground voltage measurement of any kind simply means there’s no connection. Not a short, but an open. It can’t overheat because there’s no current flow. That’s the reason there’s a difference in voltage.
There should never be a voltage difference from one end of a wire to the other. Yet that’s what the OP says he sees when he measures the ground. Measuring from the battery negative post to the other end of the negative cable, or to the engine block or the frame should all be the same reading: zero. It’s the same as measuring from one end of the negative cable to the other.
Do you, or your “experts”, have wiring diagrams for your car/truck? No? Well, here’s one: http://www.autozone.com/autozone/repairinfo/repairguide/repairGuideContent.jsp?chapterTitle=Wiring+Diagrams&partName=Chassis+Electrical&pageId=0900c15280051873&partId=0900c152800517ae Wait several minuets for all the diagrams to load. Scroll down to Fig. 46. On your pc keyboard, press the ctrl key once, and the + key twice, like this: ctrl++. Press these keys, together, several times to get the enlargement you desire.
On the wiring diagram, the starter solenoid control is different from most vehicles. See it? The red wire carries power directly from the battery positive post to the starer solenoid (which is on the starter, isn’t it?). The starter solenoid is energized when that ppl (purple) wire goes back through the ignition switch and is grounded by the ignition switch when the ignition switch is turned to START. Does this wiring diagram match the wiring diagram in your repair manual?
When the starter solenoid is energized, the current from the battery could be directed to the BODY of the solenoid and starter (internal short).
When I physically remove both the starter and alternator and hook up the +cable to the two small-wire connectors, I get +9.5V. So neither are the source of the short to ground.
These +9v readings are with the -cable removed from battery post.
HELLOKIT: Thanks for the link, but the original shop manual has all the circuit diagrams. Yes the key-to-Start energizes the signal wire that goes to the “S” post on the solenoid.
In my case, the solenoid throws the starter shaft to the ring gear/flywheel, but it just barely engages, so the starter is not energized and does not turn.
Yesterday, I removed the -cable from the battery and put the voltmeter on the ground post of the starter and the -battery post. +9.5 volts.
I speculate that the solenoid is seeing +12v from the battery and the opposite +9.5v backwards through the starter ground. That’s only a net +2.5 volts in the normal direction, not enough to engage the starter gear fully. This may be affecting/confusing the internal contacts of the solenoid, resulting in the short to ground and draining the battery to below 4v.
I’ve got to get rid of the +9.5v!!!
I disconnected all small wires from the solenoid, left battery cable on, hooked up a start button to the “S” post. Drained the first battery, perhaps because the solenoid and/or the starter internal switches were in wrong positions. [It did the same thing last Saturday on the first attempt.] Swapped out the battery and the button started the starter, turning the car engine over rapidly. The voltage across the battery dropped only to 10.4v. Several successful, long engine cranks on the same battery. [Of course, the engine couldn’t fire because of the disconnections - no power to plugs, etc.] In normal hookup, the reverse +9 volts are obviously keeping the solenoid/starter from operating normally. The test also proved that the short to ground is not in the starter or the solenoid.
I guess that is good news because you are getting somewhere, but I am having trouble pinning down such a major voltage drop. It would imho take a pretty serious cable to cause that voltage drop as most other circuits are protected by fuses. Wild guess is defrost or AC on? Can you disconnect alternator in case it is shorted? In fact maybe turn off everything electrical you can, ac, fan, lights, defrost, and give it a whirl.
On this problem, one would have to have a hands-on. I’m afraid your word-picture leaves too many unanswered questions.
You say the starter has a “ground post”. Do you mean the post the positive battery cable attaches to? Unless there is something really strange in the design, that post is positive. The starter body is ground.
[EDITED] > The purple (ppl) wire is hot (12 volts) when the ignition is at START. When you disconnect the purple wire from the starter solenoid, and measure voltage on it, while HOLDING the ignition switch to START, it should show 12 volts. The ignition switch allows voltage to the starter solenoid to engage the heavy current contacts within the solenoid which conduct current to the starter motor. Now, I’m going by the wiring diagram I saw at www.alldata.com on 04/11/09. < < [EDITED]
Does your wiring diagram agree with the one at autozone.com?
I tried your link, and just got to the site, and sign on required, I have not signed on so it may work once you create a logon.
I get +9.5 volts with alternator disconnected or out of the car. I get +9.5 volts with all fuses and circuit breakers removed from fuse panel. It must be coming from an unfused, “hot at all times” source? Everything in the car is off, ignition switch with key removed. It is NOT a “voltage drop”, it is a short from a +12 source to ground - the entire car: frame, motor, body. With ground at +9.5, the solenoid/starter malfunctions and drains the battery in “Start” mode.
What are you calling a “ground post”? Is it the post between the starter solenoid, and into the starter?
The pictures of your starter, at www.autozone.com, don’t have enough resolution to discern things in detail. If you looked at the pictures, could you describe the parts of the starter and “point” them out on the pictures?
HELLOKIT: Yea, everybody wants me to have the Elky towed to them, keep it for 3-4 days, charge me $2,000, and tell me that I have a short to ground somewhere.
On my starter, all the + red wires are connected to the large post on the solenoid. There is also a purple wire from the ignition switch connected to the small “S” post on this end of the solenoid.
My starter has a threaded “ground post” on the other end, which passes through a whole in swivel bracket, a nut tightens them to provide ground and physically support the stater from that end.
I have two connectors on the large +post of the solenoid, one single, small red wire, one with two, small red wires - either of which will cause the +9.5v to ground. But with the purple “S” wire connected, both small wires disconnected, ground = 0v, as it should be. But will try the voltage check on the purple wire. THANKS for the suggestion!!!
HK: See my 8:00PM reply to you
Do a parasitic draw test. I must say I can’t put this 9.5 volts into perspective. Do you know how to test for amperage draw? Just so you don’t blow the fuse in your meter remove the negative cable and hold a fused jumper wire (use a 10 amp fuse) between the negative post of the battery and the negative cable end.
OLDSCHOOL: I blew a Radioshack meter set on the max mAmp range trying to ascertain amps. I have an old Sears engine tester that will read amps, but don’t have the manual and don’t know how to measure amps with it [volts OK]. Can you help?
Jqutie,
I have been looking over the posts here and from what I understand there is a high current short happening while in the START mode. The only wire that could support that much current draw and not be damaged is the main starter cable. I suspect that the starter motor windings or the solenoid contact has a path to ground. I suggest you replace them both and see what happens. I know you got it work one time but the trouble may be intermittent. To prove this out you can do this. Remove the small starter solenoid lead that comes from the ignition switch and isolate it. Then try starting the car. This will activate all the circuits that are normally used in the start mode except the solenoid and the starter. If the voltage of the battery stays up you have eliminated the current path and proved the problem is with the starter.
As far as your testing method of checking the voltage on the negative battery lead while it is disconnected it really just states there is a load of some sort tied to the battery.
Well this is good and this is bad. We are going to keep a meter out of the circuit as we have a constant high amp draw associated with this 9.5 volts. We don’t need to know exactly how much just that its high enough to damage a meter set to max.
The good part is that if you have this high of a amp draw something should be getting hot and should be evident.