Volvo 240dl station electronic problems, alternator?

Hi, I've been reading a lot on alternator problems in this group. My problem is similar to the ones I've read but just a little different (of course). Car: Volvo 240 dl station 1986 manual. Problem: In a week time the car would start less well untill one day it wouldn't. Couple of guys pushed me and it worked fine driving for 10 min to a mechanic.The mechanic measured a 12.65 V over my battery with car running. He concluded that the alternator needed replacement. After replacement the V was still 12,65. Both alternators were tested outside the car and both the new and the old were good. The battery was also good although empty. The mechanic put my old alternator in, charged my battery and my car ran fine for a couple of weeks (also after not using it for 10 days, so no leak while standing still I guess). Then it started starting less easy again untill it wouldn't, I got a push again, drove home (I think the engine almost stopped a couple of times). The next day I went to my garage were I explained the story. After checking it out they told me it was the alternator and maybe also the alternator belt that needed replacement. Thanking them for nothing I went home with an according to them fully charged battery (altough they were a bit vague). A couple of days later I went for a

120 mile drive (each way) on the way back my dashboard fuelmeter and engine-temp. meter slowly went down to almost 0 although fuel and temp were fine. Also the speedometer only showed the right speed when I took my foot of the gas (otherwise to low a speed). The overdrive stoped working. To me it seemed the battery was totally empty and the alternator was not keeping up. I stopped allong the road. The fuel and temp went ok again but as I moved on everything stopped working as described before. Coming home the car wouldn't start. The V over the battery with the car off is still just above 12. The lights on the dash with key in position II work (I presume battery lamp is alternator lamp). Their are 3 wires from the alternator: Two red and one blue (thinner one). I think they're ok but i'm no expert. (wich one is the ground?, blue?)

A few things I did right before problems started occuring: I pluged in a missing fuse (the one for back-up lights etc.) and replaced some others. Since than the speedometer has been shooting up and down at certain moments. This same day I replaced some speaker wire leading it behind the dash. Since that day the "lights-warning light" also pops on when I turn on the head lights. It goes of when I turn on and of my direction lights. (:-?) Since I thought I might have pulled some wires doing that I checked the dash wiring. It looked ok apart from to loose wires of which I don't know if I need them. 1: a solid blue one. 2: a red and white one. Does anyone know what they're for. (I noticed there was another solid blue one that was connected in combination with 2 other wires (black and white and an other color if I recall correctly).

Hope anyone can help me I'm gonna be roadtripping for 3.5 weeks in 2 weeks, hopefully with this car.

Thanks. Gilean.

Reply to
Gilean
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Hi Gilean, please take a look at this link, it describes in detail the charging system of a 740 (almost the same as the 240).

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addition to that link, check the ground connection to the alternator(blue wire). If you have a volt meter, with the engine running and headlamps on, check from the negative of the battery to the following points:-blue, ground wire 0 to 0.1 Volt-Thick red wire, should be 14 Volts.-Third wire should be about 14 volts. The 3rd wire is what turns thealternator on, it applies switched power through the battery warning lighton the dash board to the brush/regulator assembly, if the battery warninglight is burnt, the alternator will not charge. Check the link, take the measurements, and report back.

Arnold

Reply to
Arnold

Hi Gilean, please take a look at this link, it describes in detail the charging system of a 740 (almost the same as the 240).

formatting link
addition to that link, check the ground connection to the alternator(blue wire). If you have a volt meter, with the engine running and headlamps on, check from the negative of the battery to the following points:-blue, ground wire 0 to 0.1 Volt-Thick red wire, should be 14 Volts.-Third wire should be about 14 volts. The 3rd wire is what turns thealternator on, it applies switched power through the battery warning lighton the dash board to the brush/regulator assembly, if the battery warninglight is burnt, the alternator will not charge. Check the link, take the measurements, and report back.

Arnold

Reply to
Arnold

Hi Arnold, Thanks for the info. I did the tests and this came up: between:

- and Green (third wire) at first 12.1 V later when remeasuring after thick red: 10.6 V

- and ground .05 V

- and thick red 10.6 V Then some other measurements:

  1. Voltage between the alternator power terminal and the battery "+" terminal should be well under 0.2V (did not know what the power terminal is)
  2. Voltage between the alternator body and the battery "-" terminal should be well under 0.2V : mine was .055 V
  3. Voltage between the battery "-" terminal and the engine block should be well under 02.V :mine was .006 V

So those last 2 look ok. Then I started measuring while revving the engine:

- and green or thick red: 9.5V then with the fan on high while revving:

- and green or thick red: 8.5V hmmmmm I thought: interesting.

The V over the battery is also going down when revving. At a certain point (I meassured this later on) 12.6 to 12.3 or so.

Then I remembered something else. The first time when they replaced my alternator and put it back in. They left out one part which they said wasn't important.. They thought it was a noize reductor but I don't know. It's a small black box (lxwxh: in cm: about 2.5x1.5x0.7) with a small metal plate with screw hole for connecting to alternator and a 3 cm black wire with a small plastic thing that says :AMP and looks like is made to glide over something for electric connection. The black little box says: Germany

2,2microF 100V- 0 290 800 036 I wanted to send a picture but my server is down.

Thanks for all the help. I hope I'm on to something. I'm suspecting there is something with my regulator or so, but shouldn't the voltage go up above 14 then???

Thanks, Gilean

Reply to
Gilean

Hi Gilean, I think that the control voltage is there to "turn on" the alternator, that is the 12.1 Volts that you measured on the 3rd wire (green). When you started the car, since the alternator is not producing voltage, the electrical load keeps draining the battery, and that is why the battery voltage keeps going down. The next step would be to remove the voltage regulator/brush assembly and inspect the brushes. It is easily done. This is a black piece located on the back of the alternator and held in place by 2 Torx screws. If the brushes wear out, the regulator will not be able to pass the voltage through the rings to the field to "turn on" the alternator. The mystery piece you are talking about is a capacitor, it is mainly there to help with ripple noise that would affect your radio, mainly in the AM frequency band, it will not interfere with the electrical operation of the alternator. You were measuring earlier voltage drops which are helpful in determining wiring conditions when the alternator is producing power, but in your case it is not. My suggestions are: -With the engine off, check the resistance from the negative of the battery to the alternator housing, it should be zero ohms. -Remove the green wire, and connect a 12V 5w bulb from the alternator terminal where the green wire was connected, to battery + and see if the battery voltage goes to 14V with the engine running. -Check the regulator brushes.

How was this alternator tested outside the car? did they put it on a test jig, or just measured for bad diodes?

Arnold

"Gilean" wrote in message news: snipped-for-privacy@y41g2000cwy.googlegroups.com...

Reply to
Arnold

Hi Arnold,

This is what came out of the tests:

-battery to alternator housing = 0.0-0.1 Ohm

- I didn't get the bulb yet.

The brushes look like this:

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(Medium).JPGOn the short side?

Then I have an other question: The fact that the V output with the new alternator was also 12.6V doesn't that mean that it can't be the brushes (or any part of this alternator for that matter)? What is left then? wiring (have I checked that all with the test i did, what about the bulb test, is that important, what do I test than?1)?

Both alternators were brought to an other garage then the one I was at and then tested, so I guess it was on a test jig... I wasn't there though , but I presume they're telling the truth about them both being fine (otherwise they would've sold me an alternator).

Thanks again for your quick response. Great help! Gilean.

Reply to
Gilean

This should be the picture link and should work this time... othewise just paste it all back togheter

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(Medium).JPG Gilean

Reply to
Gilean

Reply to
Gilean

The third time with the picture link was the charm ! The brushes look fine, there is a lot of them showing. We are running out of options here. The resistance to ground is fine, the only other advice I have for you is to check the belt tension, tighten if necessary, disconnect the 3rd wire from the alternator and connect a 5W bulb from the battery positive (also available closer at the alternator) to the control terminal (Where the green wire was connected), start the car and put some load on, lights etc. And measure again. If the voltage measured at the alternator output terminal (the big red wire at the alternator) comes to life 14 to

14.4, then the wiring to the battery charging light on the dash, (maybe the light bulb is out) is to blame. If it remains dead, check your connections at the alternator, and have it tested in front of you on a shop.

please report back, I am losing sleep over your problem.

Good luck

Arnold

Reply to
Arnold

Hi Arnold,

It seems to be very hard for me to reinstal the regulator. Is there a special trick to it? Or should I just keep trying to find the screw holes untill I go crazy (almost at that stage). I presume the brushes should be pointing upwards. Do I glide it in and then upwards so I feel pressure on the brushes? Any more things to be aware of?

Then something else: I bought this, to do the bulb test cause they didn't have anything else...

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(Medium).JPG

(again a space between ..03814 and (Medium)

Do you think it'll work with this piece of equipment?

Then I looked under the protective cap of the regulator and to me it looked a bit funny... Is that black stuff supposed to be there as protective cover or has something melted and leaked in there (I know this is probably not the smartest question, but I'm losing sleep as well, so checking everything):

formatting link
(Medium).JPGI'm almost taking this alternator out and having it tested again (Iheard of a place where they do it for free). Is it easy to take it out?But more important: also to put back in??? :-) Thanks for the help again. I truly hope we're gonna beat this quizmaster volvo.

Gilean

Arnold wrote:

Reply to
Gilean

I have vague memories of the regulator replacement in the Volvo, but normally the brushes have to be pulled back against the springs to get it to fit. IIRC the Volvo regulator has tiny holes where straight pins can be slid in to hold the brushes back, but on some regulators I've had to use thread (often tied to the braided brush wires) run out to where I can keep tension on it and then cut it when the brushes are in place.

Mike

Reply to
Michael Pardee

Hi Gilean, I have not looked under the protective cover, but that black goo could be epoxy to seal moisture out and make this regulator immune to moisture and humidity. I would not be too concerned. You will have it tested outside anyway. The tester looks, good, tie the red clip to the battery +, (if you touch the tip of the tester to chassis, the bulb should light up). Remove the green wire from the alternator, start the engine and touch the tip of the tester to the terminal where the green wire used to be, this should feed voltage to the field of the alternator, and the output voltage should go up to 14.5 V. If it does not, have it checked outside, I think it would be defective.

Good luck. Arnold

Reply to
Arnold

Hi,

I did all the test, took the alternator to a test jig and... it was fine. Whilst there I thought, why not buy a new belt... replaced it and... everything is fine.. I couldn't see the old belt slipping or anything like that.. but anyways.. problem solved, thanks very much for all the help.

Gilean

Arnold wrote:

Reply to
Gilean

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