Testarossa Battery Question

My Testarossa started up just fine yesterday morning as it always does. I restarted it after a 5 minute trip to a store close by and the battery was dead. I jump started it and tried to drive home but after about a mile everything on the car started shutting down until the engine finally died. I pulled the battery and replaced it with a new one and everything is honky dorey again.

My question is this, does the alternator not generate enough current to power the engine while it is running? I am wondering if my alternator is not putting out enough current and is the real problem of if I got off lucky with just a battery replacement. If so, this is the cheapest repair I have ever had. But my experience has me doubting this and thinking that there is a bigger Grimlin lurking somewhere else.

 

Better have the charging system checked. Sometime the internal regulator of the alternator can play tricks. The other thing that leads me to beleive that this is the case, is because of the fact the car started to shut down. That is a classic example of the alternator not charging.

 

Thanks for the quick reply. Moorespeed is at the races until May 11th so I'll have to wait a bit.

 

Is the red charging idiot light on? Sometimes you have to check it when dark outside, as it does not light well. If on, then the charging system is not functioning. If off, then something is not right in Denmark. Sounds like inadequate charge.

Jim S.

 

I had the same thing happen in a pickup truck I had. Drove about 5 miles, shut off, then it wouldn't start. I couldn't even jump it. The battery was about 5 years old and it just died. Apparently something was shorting out on the inside of it too, keeping me from jumping it. Replaced the batterery and drove it with no problems for another 3 years, then sold it. Definately the simplest solution. Hopefully it's the same for you...

 

Hi Kelly. Do you have a multimeter? Since you just replaced the battery, I would do a quick load test to check the voltage drop. With a functioning alternator, a new battery and car at idle you should see 13.8-15 volts no-load and no less than 12.5-13 volts with load at the battery (lights, radio on, etc). Any lower would suggest a problem in the charging system. Good luck & please let us know how this all turns out.

Shan

 

Just as a point, There have been quite a few problems found with a poor connection at the battery shut off switch. If there is a poor connection, the battery will not charge properly.

I would as others suggested, check the charge system but also check all the ground and power feed connections along with that switch.

best regards, Jim

 

My Generator light comes on momentarily when I start the car to indicate that the bulb is working. Then it goes off and does not come back on unless the engine dies.

I have a little gizmo on my boat that plugs into the cigarette lighter and gives a digital read out of the volts in the system. I'll drive down to the marina tomorrow and plut that little thing into my TR and see what happens. Thanks for the idea Shane.

I'll check the battery kill switch as well. I've never used it. I drive the car several times a week. Great ideas guys. Thanks for the help.

 

Usually, when the alternator starts to go, it's the rectifier bridge. As one or more of the diodes start to fail your warning light should "flicker", but we all know that our electronics are not outstanding..

Here is exactly what happened to me one day after I bought her.

Car was stone dead at the library about a mile from home.

The wife loved it, stuck in a Ferrari. - there was a police officer in the parking lot and I was about to go ask him for a jump (if you ever do this, disconnect the battery & let it charge for about ten minutes to have enough juice to get you home), but she jumped out and said: "I'll do it!" , ran over to the guy, and sweetly asked "can you give us a jump?
"Sure lady, which car is yours?" "Oh, it's that *Ferrari* over there."

He couldn't have gotten to the car any faster if I was giving away free doughnuts.

You can can change out the alternator yourself.

Go with the Ferrari Bosch item and it's about $600 -$800 from the dealer, but its the exact same item used on any number of US cars. I think mine was an exact match for a cadillac model.

I just bought mine to an alternator shop. They replaced the rotor and stator, the bridge and electronics, and did something to clean and brighten the case.
Basically, it was a new alternator. -$149.00 No more problems.

 

I think my TR uses an...... get ready for this one: <drum roll please>

AC DELCO!

should be able to get anywhere. if I remember right. its quite a high Amper.

Bill

 

You can take your car to any Advance Auto Parts store and they have a tester that will test the battery, alternator and wiring system. They do the test for free. Good luck. If it turns out to be the alternator, you can have it rebuilt for $100 or so.

 

Or, here's a quick hands on test:

Before you start the car, loosen the negative cable clamp enough so that you can remove it by twisting it off.

Start car. Twist off negative cable. -Car stops running = non functional charging system.

Car keeps running = defective battery

Of course an intermittent problem might be missed with this, but it's a fast & free test.

 

I tested the voltage with a voltmeter today and here are my readings:

12.3 to 12.4 volts while engine is off and nothing is turned on

11.9 to 12.0 volts while the engine is running 2k rpm and nothing is turned on

11.8 to 11.9 volts while the engine is running and the headlamps are on

I would have expected to see higher readings while the engine was running than when it was at rest. I'm pretty sure I've got alternator issues now. I'll take it by somewhere and get it tested next week. It's supposed to storm all weekend here in Austin.

One more thing, the red battery light does not come on in the instrument cluster. Does that idiot light come on when there are alternator problems or when the battery is low? Nothing comes on when the battery is low so that doesn't make sense.

 

I believe one possible reason that the alternator warning light may not come "on" is that there are multiple diode networks involved -- the output of one network does the actual charging (call this the "charging output"), and the output of the other network (call this the "sensing output") is just used to run the warning light stuff. The warning light only comes "on" whenever the battery "+" side (which is the higher of either the battery self-voltage or the charging output) is different (either higher or lower) than the alternator sensing output. If your alternator internals have failed in such a way that both the charging output and the sensing output are just the battery self-voltage then the warning light does not illuminate.

I can check the TR wiring diagram later to confirm that architechture, but not measuring ~14V at the battery at the 2K RPM is a bad sign either way.

 

Thanks Steve. I'm not an engineer or a mechanic so most of that was over my head but I did understand the last sentence. I'm pretty sure that I'm running on battery only right now and no charging is taking place.

If it wasn't so darn much fun to press that far right pedal it wouldn't be worth it to keep a TR running. I feel like a drug addict, I need a fix. Give me some 12 cylinder hard acceleration and a Tubi to boot. These cars sure are worth it all when they are running properly. Enjoy yours this weekend.

 

Kelly -- I checked the WD, and TRs alternators do have that set-up so the warning light system can only reliably detect (or indicate) the "alternator rotor's not spinning" problem rather than an "internal electronics bad" problem -- good luck with the fix...

PS -- I sure hope too -- it's been raining/snowing for the last three days!

 

Agreed. Sounds like it's time to get your alternator checked out as well as the contacts and grounds in the charging circuit. Also would suggest disconnecting your battery and attaching a trickle charger for now. Your battery is losing charge. With your new battery you should see a strong 12.6V (2.1V per cell) with engine off & no load. For comparison, 12.4V=25% discharged, & 12.2V=50% discharged. Below 12V is basically the "dead zone". Keep us updated.

Shan

 

Hi,

you should get around 14,5 volt at 2k rpm at the battery. 12,0 is too low.
Would check the regulator/alternator wires first. What about your belt
tension? Maybe the next Bosch Service helps.

good luck

cinquevalvole

 

I hooked up a battery charger tonight and checked the alternator belt and it is still in place. My next step is to have the alternator checked. Here are a couple of pics of my battery and alternator. I don't have a battery hold down strap. Isn't there supposed to be something to hold it still?
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Well, it's not a leather strap with a buckle

The TR's battery restraint is a "toe clamp" arrangement with a fixed bent lip on the back edge of tray 33 and the moveable clamp 34 held in place at the front by special bolt 35.

You should not have a "loose" battery (especially not the liquid-filled type)! -- but can't clearly tell from your jpeg (or your description) if yours is actually present or not.

 

There is nothing holding my battery down other than gravity. I'll have to order the special bolt and accessories in the diagram you sent.

I started the car today and removed the ground lead from the battery and the engine died immediately.

 

khayes - Gabriel's suggestion of removing the battery cable has to be examined. When removing the battery from the system, everything will die. The electronics and ignition system need the 12 volts to operate. Alternators do not generate voltage. They generate current, that when passed into the battery, produce a voltage. Thus, unlike old systems (pre-electonic ignition), removing the battery will lead to the "door nail syndrome", as in, dead as a door nail.

I am not sure that you can read much into the result.

Jim S.

 

Jim, I did not know that newer systems needed a battery to operate once the engine was running. - Learn something every day here.

So, does that also mean that a battery with an impared function, such as a bad cell, will degrade system performance?

Also, if the battery is somehow damaged while driving, such as in racing conditions, or running over a curb, or simply fails in some manner, the car dies?

 

Gabriel - Yes - cars with electronic controls, ignition, computers for timing and fuel injection, etc., need the battery to function. If one removes the battery from the system, the car will stop.

A failing battery is one that does not hold a charge. One or more lead plates have failed. However, while in the charging system, current pumped into the battery by the alternator will find a resistance, and consequently a voltage will be created (volts = current x resistance). The current flowing through the battery will move electronics from solution to plate (or reverse), and this is how a charge is induced between the battery terminals.

Batteries rarely, if ever, fail catastrophically. They die a slow, low voltage death. Hope this helps.

Jim S.

 

Wow Jim, that is very informative. -Does then a spark plug (gap) have the resistance nesessary to create firing voltage?

I'm just trying to figure out how the older pre-computer controlled car will run with no battery.

On my 69 Boss 302, I had installed a dual battery system with a large relay setup. One just to start, the other for everything else.
I put one in the trunk, the other in the factory position.