Once again when they were tested at the store did you read the VOLTAGE output and was it 13.8 or better.

 

Thanks. but this is the 4th new alternator I've tried. The first three from AutoZone - all tested ok on AZ equipment. They finally banned me from the store! So this 4th one is new and I had it tested at ORyley's before it left the shop. I think it's safe to say something's wrong with my wiring.

 

charge the battery.

1) start the car. put one volt meter probe on the ground screw of the alternator, and the other one on the battery - terminal (poke hte terminal not the clamp). should be very close to 0 v.

2) put one volt meter terminal on B+ and the other on the battery + terminal, again should poke hte battery terminal itself, NOT the clamp), also should be very close to 0V

3) stop engine. turn key back on, does the battery light on the dashboard come on? start the engine, does that light go out ?

 

I think its a good idea to go back to the beginning! I think the OP is just going around in circles.

Although I asked earlier ,what is the voltage at the D+ wire when it's NOT connected to the ALT. Is it still 1.5v or battery voltage??

 

Sorry but you didn't answer the question I asked. So did YOU see a volt meter and was the voltage output 13.8 volts or more when the alternator was tested. If it was then you have a wiring problem.

 

Do we assume that this has been resolved.

 

Mr. Jagtoes! Happy to see you remember my problem. I wa s going to respond to you and Pierce's latest comments but in getting my numbers together forgot to get the voltage at alt. D+ with OUT the wire . . . I did a diode test on that 4th new (rebuilt) alt and thought I shouldn't get readings in both directions from the D+ post - and so traded that alt for the now 5th one since November.Then I realized my mistake - that diodes behind the D+ make it a Ground when not spinning. But still - no charge. Still get about 1.5 volts at D+ with everything hooked up and running. This 1.5 volts seems to be the only clue. Tested all resistances, cleaned all grounds and hot connections - dash light goes on and off when it's supposed to - and linking D+ to B+ on the alt does not produce a charge.
Curiously - if the car had been running in November I'd have returned to New Mexico
and now I've been offered a tiny house in the first tiny house village in the country! But still no wheels!

 

Try reading my last post (get someone to translate it to you) and tell me what your reading is. The voltage at the BIG RED WIRE. My bet after all of these posts is that there was nothing wrong with the alternators but a problem with the operator.

 

Jagtoes - Great, so now you want to get rude. Read my previous posts and you will see I've left no stone unturned. If you don't have the attention span for that, get someone to translate it for you. My figures for every aspect of the situation are posted. I'll add the latest - .o4 volts at the D+ post, car running alternator spinning, wire to dash light disconnected. The voltage at the BIG RED WIRE only ever matches the charge of the battery - as is posted four or five times in this string. I can understand that your brain could be frozen with the weather you're getting in NY.

 

dagaan, stop right there. I've asked multiple times for you to take a very specific set of readings, in a particular order to help trouble shoot this, you've NEVER replied with anything but bull**** answers, you've never given me the readings test. not sure why I'm even bothering anymore.

each of those tests, there's things to look at if the test gives different results, I'm not about to spell out the whole trouble shooting tree again. this is basic electrical troubleshooting. telling us you tested everything is NOT THE RIGHT ANSWER.

 

Sounds more and more like a troll here. I'll leave it to him to solve his own problems as he has demonstrated his inability to accept any support. We're done here. Time to move on.

 

Pierce - I don't get your response here. I appreciate your info based responses (unlike Jagtoes who doesn't appear to have read the figures I've posted) and have tried to give you every detail of my situation with figures across a few of the strings I've started on this, that you've responded to. I sense there is DISBELIEF that my non charging alternator(s) could be impeded by some AS YET UNKNOWN FACTOR as all the usual diagnostics for this problem do check out; resistances to main + and - cables are .o1; ground and positive connects to battery have been cleaned and re-attached. From batt - POST to alt. case .01V's; My warning light functions - goes off with engine start - light comes on if D+ grounded; in shop tested alt.(s) show only 1.5 V's with engine/ atl running; (this is the only clue out of spec, as you told me that V should be 7-9V's from both your manual and from testing your 740) - Alt. spinning, engine on, shows only the exact voltage at alt B+ post as current batt B+ post reading with engine running. Not anywhere near 13.5 or 14.5 - only 12.2 when battery is 12.2 . With D+ wire off alt, and alt spinning, D+ post only shows .04 V. These are all the possible readings. Since it's a closed circuit - not involving ECU or Throttle PS - and all five new, remanufactured, shop tested alts were good - the alt not producing 14V's has got to be due to the regulator informing the alt to NOT produce juice. But why? This problem is not unique to me -as on YouTube there are half a dozen different vehicles that have this problem - with no one posting a solution. I've found a 'self exciting Delco alternator with no D+ post - only has a B+ post , that I am going to put in, as ONLY something going on with the D+ circuit has to be preventing a charge. Again there seems to be just plain disbelief that this problem can exist - but it does! Thank You for participating. Amen.

 

this is strange... re post #9 + #16 did you try revving the engine up
to see if the alt would 'self excite' ?

 

Before you get to deep into this discussion ask how is it that 5 alternators were tested at the suppliers and they all worked meaning that the output met specifications . So if that is the case it's not an alternator problem it's an operator problem.

 

yeah one or two maybe, but 5? sounds odd...
i guess if the OP didn't ground them properly that would explain it..

 

Strange is the right word. Yes I triy revving up past 2000 rpms with each new test. Supposedly you can also excite the alt by linking B+ and D+ posts on the alt - no luck there either.

 

Ha ha! Now we're getting somewhere. Yes, how could an alt test (or 5 ) on the in-store equipment yet not work on my '86 240 DL. But then why, all other elements of the circuit functioning, does the alt only put out 1.5 volts, engine/alt spinning - when the specs call for (from the great Pierce) 7-9 volts? Jagtoes - I'm not intentionally trying to complicate things with misinformation. I've tested every aspect of the circuit and get no charge. I tried new alts because it doesn't make sense so I concluded I was somehow getting faulty rebuilt alts from Mexico. My problem is not unique to me as I've come across numerous posts on YouTube of people with this strange problem on different types of vehicles - and they were also baffled. Thank you for your interest. Dagaan

 

Silvermine - I did resistance tests on both ground and hot cables from battery to the starter and from there to the alt. I disconnected and cleaned and re-attached each connection. In case the hot cable that goes from the starter to the alternator (which vanishes into the harness) was somehow faulty, I replaced it, going outside the harness. No differance. Likewise with the D+ wire that vanishes into the harness - I replaced it straight from the D+ post to the relay box on the firewall. The D+ circuit from D+ to relay on the firewall to key, light, fuse - works and does go off when engine is started. Neither the ECM or throttle postition sensor is involved, on this year's model, (according to Pierce) with that charging circuit (but I did clean the TPS and used electrical connector spray in reconnecting) - so that it SHOULD be a simple closed circuit from D+ back to B+ on the battery. The only clue I think is the 1.5 volts on the D+ wire, engine/alternator turning - above 2000 rpms. Why is it not 7-9V's?

 

What is the voltage on the D+ wire when it's disconnected from the alternator, engine off? Does the voltage go up when disconnected ?
If the voltage go's up, that may indicate that there is a bad connection somewhere in the harness going back to the "Battery" indicator.
If you have bad connection due to corrosion on that wire that feeds D+ will not supply enough current to regulator circuit for the alternator to start charging.
The reason your charge light go's out is because the output is from the alternator is enough so that the "light" is longer at ground and no current is flowing.

 

"a bad connection somewhere in the harness going back to the "Battery" indicator.
If you have bad connection due to corrosion on that wire that feeds D+ "

The car is an '86 model year. I wonder if the engine harness has ever been replaced. If it's original that might very well be the source of the problem...a corroded engine harness.

From what I understand that a common issue for Volvo in that year... and other years as well.

Its just one of the reasons I limit myself to only '89 and later redblocks.