Apparently I may have been on the wrong track with my no start problem. Thought it was VATS but there is more to it.

So last night I charged the battery since I had started to run it down. I charged with the neg. cable unhooked. After the battery was charged I tried starting the car. It turned over 1 time and then everything went dead, no dash lights or interior lights and of course no crank, atleast before I had dash lights. So I check the battery and it only shows ~9 volts(touched the cable ends with the meter terminals). I found this very strange so I went this morning and had the battery tested and it tested bad so I got another one, optima red top. I got home and put the battery in the car and upon hooking it up all the lights came on as they should. I tried to crank the car and same thing as before, 1 turn and everything went dead. I checked the battery at the cables again and same thing, 9 volts (actually that is what it averages it jumps constantly between 8.5-10). So I measured the battery across the top posts that aren't being used, 12.5 volts with the cables hooked up to the side terminals. I unhooked the cables and measured across the side terminals and 12.5 volts. I hooked the cables back up again and only 9 volts across the cables and no lights ect. I also cleaned the cables with no results.

Here is what I have done thus far. I unhooked the neg. cable and read the amps across it to the battery and had 30. I checked the ohms as well and showed .410, which I assume is 410 ohms. I then had some one hold the meter terminals across the cable ends hooked up to the battery where it would read 9 volts and pulled the fuses one by one, no change on any fuse or circuit breaker. I also verified that the negative cable is still hooked to the frame. I can get the car to start if I use my jumper box to give it the 12 volts it needs, but I turned it off right away in fear of damaging something if it is shorted.

Any suggestions as to what would cause this? I am usually pretty good at tracking the problem if I know what to look for, but I am at a loss on this one as to where to start.

 

Starter and lead to it. Sounds like a partial short. Could cause a fire so do not hook up the battery till you find it. Use an Ohm meter on it from ground wire to hot wire and report back what you get.

 

.410 reading on your digital ohmeter could mean .41 ohms, about what you might get if you touched the ohmeter probes together (usually they are 0.2 ohms or less). Most digital ammeters won't read higher than 20 amps, so your reading of 30 amps is suspect. Also, if your electrical system is drawing 30 amps, you would notice a pretty good spark when you connect the neg battery cable to the battery. When cranking an engine, the battery terminal voltage should never fall below 9.0 volts or you have a discharged battery, poor cable connections, or a battery at the end of its life. Battery voltage should never jump around like you observe. Possibly you have a battery cable that no longer has a low resistance connection from the battery lug to the wires in the cable. Where do you connect your jumper battery cables to start your engine? If you connect them to the car battery cable lugs, then you have another defective battery. If you connect the jumper battery ground to the engine, then you might have a bad neg batt cable or its connection to ground. If your new battery has 12.0 or lower voltage, charge it up. No load battery voltage tells you the state of charge, 12.0 or less, discharged and 12.9 or higher, fully charged and linear in between (12.5 v is 50% charged).
With the battery charged and cables connected, measure the voltage from the neg batt terminal to the engine and first turn on the headlights, the voltage across the neg cable should be very close to zero. Then have someone attempt a crank, again the voltage should be very low, under 1 volt. If you see high voltage (more than 1 volt) during cranking, then check the condition of the neg batt cable connection to the frame and also check the large wire from the frame that goes to the rear of the left head. Starter current flows throught these two wires and they need to have low resistance connections.

 

First off thanks for all your help with my posts. I'll try charging the battery to get 12.9 or better volts unloaded. I can't help but think that if it is just a bad battery then something on the car is causing it. The one I just replaced was a red top only 3 months old. Also I don't have a "large wire" going from the frame to the left head, I have a metal strap going from the left frame rail to the left side of the block and a large wire from the battery to the same place on the block, I assume this is what you are talking about. I will pull all the neg connections from the battery and clean and report back.

Oh and about the ohm reading, when I measured my key pellet it measured .877, which several of you said was 877 ohms, so I assumed that the .410 reading was 410 ohms. I will also verify the apm reading I got. The meter I have does not have the manual with it so I'm guessing on the operation of it and the screen does not tell you much as to what setting it is on when it comes to anything like amps and ohms. I mainly use it for voltage readings.


Redeasysport,

I'll check out the starter too like you suggested, I already got under there and made sure the wires weren't loose or had gotten burnt, my headers run pretty close to there.

 

Little more info. Didn't test the ohms, but I did take the three wires off the starter, two power red wires, one with fusable link and the other from the battery. Tested for continuity from the block to the two red wires, no short. Tested from purple wire to the block(ground) and had continuity, this is with the wires disconnected from the starter. I referenced my electrical helms manual and if I am reading this right, that purple wire should be a power wire coming from the neutral switch in the console which is fed directly from the ignition/starter enable relay, not a ground wire and therfor should not have continuity to ground. Let me know if I am incorrect on this, but if I'm right that should be whats causing the problem.


Edit - Just pulled the trans postion sensor and wiggled the wires going into the dash, no more short to ground on the purple wire. Guess I'll be going into the dash . Do either of you see a problem with simply running another wire from the switch to the starter, I would think this would be easier than tearing into the harness in the dash.

 

The purple wire on the starter motor is the solenoid connection and this purple wire goes to the gear selector switch and it should read infinite resistance, ign off. This wire has 12v on it when you hit , "crank". The starter solenoid requires moderate current to pull in the solenoid and if you have a poor connection to the battery (through the ign sw start contacts, start enable relay contacts, and the gear selector switch, then the starter solenoid won't pull in hard enough to force the large copper contacts together at the end of its stroke to supply enough current to the starter motor which requires 100+ amps. Another possibility is that the copper contacts in the starter are burned and pitted and don't make a low resistance enough connection to supply starter motor current. If you can repeatedly hit crank and finally the starter cranks the engine, then you need new copper contacts if you want to work on the starter. A good test is to jump 12v to the purple wire and see if the starter cranks. If it cranks this way and won't crank with the ign sw, then something in the solenoid circuit has resistance preventing the full 12v from being applied to the starter solenoid on the starter (purple wire).
This may not be your problem, but we have had more than one CFer get defective Optima batteries from the dealer. It worries me that your jumper battery starts your car but your new Optima doesn't.

 

Charged the battery to 13.5 volts out of the car. Within an hour it was down to 11.X volts. I'll be getting another battery tomorrow.

 

Don't get another Optima! Get your money back and buy a conventional battery, they cost less, they have higher amp hour capacity, and they work from the dealer!

 

I know the gripes on the Optima batteries. I am however one of the big believers in them though. I have one in every car/boat I have, and this is the first time I've had a problem with one. The one in my boat cranked right off after being set up for 5 months over the winter and runs a stereo for hours without having to worry about it. I guess I've just had good luck with them thus far is the reason I won't discount them yet.


Secondly though the battery was not in the car when I tested the purple wire to the starter and found a short to ground. My meter has a setting as most do to touch the leads together and it beeps when they are connected. I didn't think this was supposed to happen when one lead was touched to the wire end and another to the block(wire was unhooked from the starter when this was done). Any thoughts on this. You seem to be in the know on electronics.

 

Your ohmeter beeped with the purple wire disconnected at the starter because the cold start injector has a thermostatic timer connected to the purple wire to ground. You can unplug the cold start injector and the purple wire should be open circuit when disconnected from the starter and the ign is off.

 

'90 model, no cold start inj. Don't have time to work on it today. I'll post back later this week with results and/or more questions. Thanks for all your help.

 

Was there ever an official resolution to this?