Team, as some know I have been chasing electrical gremlins. I think we have fixed the shorts, but have damaged another battery, third this year. Unless it sits on the charger and is at peak power it won't start the car. I am getting free replacements and installs from my shop, but it means we keep using World Pack batteries. They don't seem to take well to being drained. I am looking for recommendations on a stock size battery that can take some abuse.

Based on my charger I seem to need 13.5v in order to start.

Anybody know what the behavior of the cars security system relative to starting?

 

Security system - What year car are we talking about?

When you say it won't start the car, does it turn over at a good speed. If it does, have you checked for spark.

Draining a battery is not good especially for any legnth of time. New batteries will tollerate it more so than an older batttery. Did you ever do a current draw from the battery when all is off?

I think we need to get to the root of the problem but not exactly sure what it is till I hear more detailed information.

What happens if the voltage is below the 13.5 when trying to start.

 

I think I have read a couple of your previous threads.

Before you replace the battery, check again for a parasitic drain on your batter. With the car off, doors closed, and hood lights off (a lot of people miss those) you should be pulling less than 0.1 Amps. 0.05 and below would be what you really want.

If you don't have a draw while the car is off and you are still blowing batteries, it's a problem with the ignition. Starter or even the distro/spark. Going dead isn't the only thing that kills batteries. If your distro is sucking down a lot of amps constantly, then your battery gets hot and breaks down.

I use interstate batteries and have never had a problem with them.

 

Agreed...

see if there is a real problem first. If there is a big drain thats a short or some other drain on the system, the battery is the victim, not the bad guy.

If/when all is well with the charging system, make sure the cables are good, and starter connections are tight. New cables on 25 yr old cars is advised.

I had an Optima ($200 battery) that was actually shorted on 1 cell and got replaced under warranty by the top of the line that O'Reillys carries...duralast gold? I'll have to go look. The Optima spun the starter pretty good...long cranking when needed. The new wet-cell dura... spins it like it was new. Its got at least 150 more CCA than the stock requirement, and I've replaced cables and even added heavy grounds. You are stuck with the dimensions of the stock battery because of size limitations so get the best that money can buy in that size. AT least a 3 to 5 yr replacement warranty. The less the warranty the less the battery.
I would run an Optima again...they just did'nt have my size when I turned my old one in for warranty so I took whatever was available. It works...5+ yr full warranty...I'm happy.

Your starter is suspect....or the connections. It does not take 13v to crank. A decent starter on a near stock engine will spin it at 10.5 to 11volts. Takes more voltage to fire the HEI than it does to turn the starter...
Its the amps that matter more. Poor connections mean less amperage (weaker) getting to the starter motor or not enough to throw the solenoid. If it cranks slow...the starter might be dying. Check for too much advance in the base timing too.

 

Car is a 1990 Z51 6sp. Battery, Starter, Fuel Pump are all new in the 8 weeks. There was a short in the dash after the steering column rebuild and that was corrected last week. There is fuel pressure at the rail. There are two behaviors, on is the car cranks but doesn't fire, this can be fixed by upping the battary charge. The other is it doesn't crank at all, maybe you hear the solinoid. Problem existed before all the afore mentioned parts were replaced.

 

Agreed need a lot more or better detail on what is going on. But if you are talking a fully charged battery and slow crank you need to check how many amps your starter is drawing, Voltage drops ect. One thing that does amazie me is they keep replacing the batteries. I have never heard of that brand of battery nor do I have any idea who your shop is but I would think that the batteries have to be testing bad for them to replace them. There are some real junk batteries out there.

 

when it cranks and as you say no fire is it cranking at a normal speed? And what happens or how long do you have to wait for it to crank when it will not crank

 

It sure sounds like a bad connection between the battery positive terminal and the starter or the battery negative terminal and the engine block.

I had a battery leak acid and it ate up the wire in the cable. You couldn't see that anything was wrong on the outside but the copper was gone...

 

Sounds like a bad solenoid …bad starter. It might need full voltage to pull it in. Aside from the possible bad battery connections as already discussed, the starter is just probably old and tired and a new one might be a good start to resolve the problem if nothing else is found.

When you get the cranking problem resolved, and if the spark looks OK, you might turn your attention to the injectors on that year car. They can definitely cause a starting problem.

 

Starter is brand new, and the old starter behaved exactly the same way. Pretty sure it's not the starter.

 

If you have a spacing or shim problem with the starter to the mounting, you may have a mechanical probelm rather than an electrical problem.

 

Has anyone at this shop removed the battery tray and checked ALL the fusable links and connections to the Positive jumper post behind the battery? These links cannot be seen even with the battery out...it takes a little effort but many low voltage/poor connection issues begin within 10" of the battery in the small and larger gauge wire thats exposed to fumes, electrolysis and plain ol aging.

The cranking but not firing are unrelated. That well might be a VATS issue. There is nothing that I have ever seen that makes me believe that the ignition will not fire if there is enough power to run the starter. Upping the voltage can only damage things...
A voltage surge can do all sorts of damage to solid state circuits. Thats why our voltage regulators are so critical...if we allow much of an over charge we destroy other things. About all out system can tolerate is slightly over 14. If its ever hitting 15+ there is a problem. The alternators will give that much or more, but the system can't handle it.

If that HUGE draw starter motor runs...there is enough voltage to power the HEI or Opti, whatever your ign system is.

 

If you connect a voltmeter to the positive big wire terminal on the starter, then you can monitor what voltage the starter is getting. Use some long clip leads to connect the voltmeter so you can have it on the top of the car and see it. If you have voltage drop of more than 1/2 volt or so compared to the battery voltage (like 2-8 volts drop) then there is a cable problem.

Then at least you will have some real data and have a better idea of which way to go without guessing.

 

Are we fixed yet?

 

nope some more parts in bound to bypass VATS.