1990 Volvo 240 DL Charging System Problem

PaulSimonon · Post by **PaulSimonon** » 27 Jan 2010, 09:27

I'm attempting to sort out some problems with my 240. When driven with the headlights on for more than 20 minutes or left overnight, the battery will die and the car will either not start or will begin to die. If the battery is recharged, it will start up again.

When driving, the headlights and interior lights begin to dim, the radio is cut off, but the car will continue to drive for awhile. Eventually it will stumble and sputter off.

The battery has been recently replaced and there is no corrosion on the terminals. The last time I checked it before it ran, the voltage across the terminals was appx. 12.67V, then after being started dropped and remained for the next minute or so at around 12.48V. This leads me to believe the alternator is failing?

I also attempted a parasitic draw test, but I am not confident that I performed it correctly. With the car off I removed the neg. cable from the terminal, connected the pos. probe of the DMM to the neg cable, then connected the com of the DMM to the neg terminal. In the 200mA range on the multimeter, I recieved readings that would jump anywhere from 12-24mA. The battery had not been recharged at this point, and was at somewhere around 8.5V.

Is this the proper procedure, and do the readings seem to be within spec?

Also, the car will sometimes decide that it does not want to go forward in D, but will drive fine in R,2, and 1. I'm not really sure where to begin looking to figure this one out.

Thank you for your patience, I know it was long but I'm trying to provide as much information as possible. I appreciate any help provided.

Post by **jblackburn** » 27 Jan 2010, 09:41

The last time I checked it before it ran, the voltage across the terminals was appx. 12.67V, then after being started dropped and remained for the next minute or so at around 12.48V. This leads me to believe the alternator is failing?

Yes. That voltage is far too low, a healthy alternator will put out upwards of 12.8+ V even under a heavy load. Without a load, you should be seeing numbers in the 13's or more.

I think 12-24 mA is acceptable for everything being switched off, as some things remain in 'standby' mode, but with a fully charged battery that current could be higher, and would explain draining it overnight. You did the test correctly in my book. Pull fuses and see if you can get that number to go down. What happens if you leave the battery disconnected and reconnect it in the morning?

I don't know about the 240 transmissions, but low battery voltage on most cars will cause strange funky things to happen. My Honda idled at nearly 3 when its alternator went kaput.

PaulSimonon · Post by **PaulSimonon** » 27 Jan 2010, 10:00

jablackburn wrote: I think 12-24 mA is acceptable for everything being switched off, as some things remain in 'standby' mode, but with a fully charged battery that current could be higher, and would explain draining it overnight. You did the test correctly in my book. Pull fuses and see if you can get that number to go down. What happens if you leave the battery disconnected and reconnect it in the morning?

I don't know about the 240 transmissions, but low battery voltage on most cars will cause strange funky things to happen. My Honda idled at nearly 3 when its alternator went kaput.

It's sitting on the charger right now, and I figure I'll redo the draw test with a full charge and see if the current is increased and either way begin pulling fuses.

I haven't tried to leave it disconnected overnight, but I will tonight and see what happens and let you all know.

What would be the most inexpensive acceptable route in the event that I have to replace the alternator? Any rebuild kits floating around?

Post by **jblackburn** » 27 Jan 2010, 10:03

What would be the most inexpensive acceptable route in the event that I have to replace the alternator? Any rebuild kits floating around?

Junkyard/used one, but then you don't know how long that's going to last either. Look on Ebay. 240 alternators are pretty cheap though, you can get a rebuilt one with a 12-month warranty for ~$130.

http://www.drivewire.com/vehicle/volvo- ... ator/#1990

Post by **cattledog** » 27 Jan 2010, 11:13

Voltage should be between 13.8 and 14.2 when running.
On the back of the alternator is a voltage regulator with integral brush set, it's probably worn out. remove the regulator, go to the dealer and get a new one, as I recall about 75.00. Make sure you disconnect the battery before you mess with it. Oh yeah you may have ruined your battery if you discharged it too many times...that is unless it a deep cycle marine battery.

Post by **billofdurham** » 27 Jan 2010, 12:19

Your procedure to trace a parasitic draw was correct but your battery voltage was way too low. This test should be done with a fully charged battery or the draw readings will be wrong. You should wait 30 minutes after disconnecting the negative lead to allow all systems to go to sleep.

Before checking for a parasitic draw you should test for a major short. Remove the positive and negative cables from the battery. Put an Ohm-meter across the positive and negative cables. If your reading is close to 0 Ohms then you have a direct short. A normal reading will be about 150 Ohms.

For parts for the alternator check our sponsors at the top of the forum. I have only looked at one and a new regulator is between $24 and $32.

it does not want to go forward in D, but will drive fine in R,2, and 1.

First step is to check the transmission fluid for level and quality. The level should be checked when the transmission is at working temperature, usually a run of 15-20 miles will achieve that. With the vehicle on level ground and engine idling select each gear in turn, pausing in each one until you return to P. With the engine still idling remove the transmission dipstick, wipe it with a lint free cloth, replace it and then remove it again. The fluid level should be between 'min' and 'max'. The fluid should be red in colour and not smell of burning.. If the quality is good but level low, top up the fluid. If the quality of the fluid is suspect, change it. The fluid on 1990 240s should be changed every 20,000 miles.

Bill.

PaulSimonon · Post by **PaulSimonon** » 28 Jan 2010, 12:36

I retried the current draw test on a fully charged battery, and got similar but slightly higher readings, still less than 40mA.

The battery held its charge overnight with the cables disconnected, and the car started fine when they were reconnected.

I tested for the short and had readings of between 160 and 180 ohms.

I have also not tried to see what happens if I try to let the car sit for awhile with a full charge and start it later, I'll investigate further tonight.

The transmission fluid will be checked shortly and I will let you all know the results. I have already checked it while it cold, and it was within spec on the cold side of the dipstick, but I'm gonna let it get warm and recheck as suggested. The fluid was red and did not look to be contaminated.

Is there a way to check my current regulator to see if it's functioning?

lummert · Post by **lummert** » 28 Jan 2010, 14:09

Is the alternator belt tensioned properly? A loose belt will cause the battery to discharge while driving with the headlamps turned on.

Post by **cattledog** » 28 Jan 2010, 14:17

What's the voltage at the battery when the car is running?
13.8-14.2 is what you should see, if not, the regulator or the wiring is goofed. Did you check all the fuse and roll them all, spray them with contact oil.

PaulSimonon · Post by **PaulSimonon** » 28 Jan 2010, 17:06

The voltage drops when running, immediately to about 12.46V, and continues to drop from there.

I would suspect that the fuse is fine, since the starter is run on the same circuit and the car starts alright as long as the battery has a decent charge on it.

How would I go about checking belt tension, just check the belt's deflection?