• Hello Guest, welcome to the initial stages of our new platform!
    You can find some additional information about where we are in the process of migrating the board and setting up our new software here

    Thank you for being a part of our community!

Volvo 240 alternator issues

At this point, I would try disconnecting the exciter circuit from the instrument panel side instead of at the alternator. Unpin the red wire from #11 and see if that changes the scenario.

What your maps don't show is D+ is used as an "engine turning" indication by both SRS and ABS in later models, and for AC delay in earlier models.
 
Try removing your MS3x relays, and your AC relay (right side of console) and see if the symptoms change.

Assuming the '87 USA greenbook is similar to your wiring, and that it's intact and non-shorted, then I think the behavior you've described follows this circuit path:
- Alternator D+ wire to dashboard 31/11 pin (big round connector)
- Through battery warning lamp to speedometer(tachym?tre) connector 233/3
- To ignition switch pin 15 via R-SB wire
- Through ignition switch to pin 15l (or whatever it's called, it looks like the 2 pin 15s are connected within the switch) to BL-Y wire
- And the BL-Y wire goes to lots of other stuff that uses switched +12v.

The strange part is that unplugging the ignition switch stops the engine. Are any of the MS3x relays wired to the coil or switched BL-Y wire?

[I'm assuming that the green headlights-on lamp is for European daylight running lights, and is behaving normally.]
 
bobxyz said:
Please post a diagram of your MS3x relay connections. I'm wondering if you have some weird backwards power path that provides enough voltage on the switched +12 wire after turning the ignition off to keep the LH ECU/EZK on.

Normally, the ECU senses the switched +12v voltage and energizes the two halves of the system/fuel pump relay.
Click to expand...

I put a new fuel pump relay, and new wires all the way back to the walbro in tank.

I put a new big gauge wire from the battery to a distributor, then relays and fuses. All new. I didn't want to mess with any of the existing harness.



Here is the engine :




Now you should know that apart from all that, car works like a charm (well apart the ****ing TTV flywheel / 850R clutch combo slipping on me whenever i see boost).

I will take a picture of where i spliced in for switched +12v to trigger my main relay.


cleanflametrap said:
At this point, I would try disconnecting the exciter circuit from the instrument panel side instead of at the alternator. Unpin the red wire from #11 and see if that changes the scenario.

What your maps don't show is D+ is used as an "engine turning" indication by both SRS and ABS in later models, and for AC delay in earlier models.
Click to expand...

My 240 has none of these option. You sweat like a man, brake like a man an die like a man lol :rofl:


bobxyz said:
Try removing your MS3x relays, and your AC relay (right side of console) and see if the symptoms change.

Assuming the '87 USA greenbook is similar to your wiring, and that it's intact and non-shorted, then I think the behavior you've described follows this circuit path:
- Alternator D+ wire to dashboard 31/11 pin (big round connector)
- Through battery warning lamp to speedometer(tachym?tre) connector 233/3
- To ignition switch pin 15 via R-SB wire
- Through ignition switch to pin 15l (or whatever it's called, it looks like the 2 pin 15s are connected within the switch) to BL-Y wire
- And the BL-Y wire goes to lots of other stuff that uses switched +12v.

The strange part is that unplugging the ignition switch stops the engine. Are any of the MS3x relays wired to the coil or switched BL-Y wire?

[I'm assuming that the green headlights-on lamp is for European daylight running lights, and is behaving normally.]
Click to expand...

I remove the original coil for a wasted spark VW Golf one.
About the lights, i had them on because it was dark outside. But yeah it is normal.
 
kingkong said:
...
My 240 has none of these option. You sweat like a man, brake like a man an die like a man lol :rofl: ...
Click to expand...

I think I'd still try disconnecting the other end to see what happens. I'll tell you why. Indeed, in North America, the 89 year did not offer ABS or SRS, and by then the AC delay took its motor-running clue from the ignition-switched battery, not from 61/D+. But the cluster still had foil between connector 31 pins 11 and 6. In your map I see 6 being shown for the Japanese market exhaust gas temperature sensor (item 152), so I'm curious what is actually pinned on the harness in your car.

The warning lamps just can't supply enough current to keep much more than a relay coil pulled in once already energized; certainly not enough to generate spark, but as Bob wonders, that is what seems to be happening. But a second path, external to the instrument panel could indeed find its way to the engine management.

Edit: I think Bob is right. I know nothing of megasquirt/spark, but I might design it so the power consuming stuff like the ignition coil gets current from unswitched battery by providing its own switch or relay, thus offloading the car's ignition switch and only sensing its voltage to turn it on. The warning lamps could provide enough current to keep that sensing on from the output of the turning alternator on D+. Easier than unpinning the red wire: Pull the 4 lamps. Maybe pull the service lamp if your car is so equipped; the drawings here don't show that one. If that's it, a simple fix might be just adding a decent load taking from switched battery, such as a courtesy lamp for example.

A common example of this symptom where the car could not be shut off at the ignition switch occurred frequently as a result of the faulty engine harnesses with crumbled insulation of 1980-87 where the red wire for D+ shorted to the blue ignition-switched battery wire inside the vinyl sheathing near the firewall plug. No reason for me to think your 89 has insulation problems, but the symptom was identical.

Your connected D+ wire should have about 1.8 volts, thereabouts, with engine stalled key on. That provides about 10 volts for the lamp test.
 
Last edited:
cleanflametrap said:
In your map I see 6 being shown for the Japanese market exhaust gas temperature sensor (item 152), so I'm curious what is actually pinned on the harness in your car.
Click to expand...





I don't know what is the purpose of this part and i don't know if i have it in my car.

cleanflametrap said:
The warning lamps just can't supply enough current to keep much more than a relay coil pulled in once already energized; certainly not enough to generate spark, but as Bob wonders, that is what seems to be happening. But a second path, external to the instrument panel could indeed find its way to the engine management.

Edit: I think Bob is right. I know nothing of megasquirt/spark, but I might design it so the power consuming stuff like the ignition coil gets current from unswitched battery by providing its own switch or relay, thus offloading the car's ignition switch and only sensing its voltage to turn it on. The warning lamps could provide enough current to keep that sensing on from the output of the turning alternator on D+. Easier than unpinning the red wire: Pull the 4 lamps. Maybe pull the service lamp if your car is so equipped; the drawings here don't show that one. If that's it, a simple fix might be just adding a decent load taking from switched battery, such as a courtesy lamp for example.
Click to expand...

That makes perfect sense because all my relays are downstream of the main relay. So your theory could be right, as it would only require the power to keep only one relay ON in order to keep the engine running, including fuel pump, coils and injectors.

I will try to remove the bulbs right away and report back. Thank you.
 
You guys are ****in rockstars.
I put the exciter wire back in the alt, and pulled out the battery bulb in the dash and guess what, it stalls perfectly.

This is a great temporary fix.

Now here is where I picked up my switched +12v for the MS relays. Right behind the glove box.
The pickup is the yellow clip on the red wire.





So before I go deeper in the dashboard, looking for the AC relay (dunno why I should have one since the car never had it?), do you guys know what this plug is feeding, and does it confirm your theory even more?
 
Seeing your pictures, and re-reading your posts, I misunderstood your setup. I thought you were still using the original LH ECU and Ignition setup, with a piggyback MS3x. Instead, you're using only the MS3x, with it's own wiring.

So, the current issue is that MS3x doesn't shut off when turning the key off. An example MS3x wiring diagram is shown here: http://www.msextra.com/doc/pdf/html/MS3XV30_Hardware-1.5.pdf/MS3XV30_Hardware-1.5-17.html

Do your main power and relay connections match this diagram exactly? If not, please post your power/relay diagram.

From your original pictures, I noticed that the gas gauge drops, but doesn't go to zero, with key off. This implies that there is still voltage at the cluster, maybe 7volts as a guess. I don't know if running your alternator originally without a proper big ground wire could have damaged it. I'd pull the alternator and get it tested at an auto shop to see if there is some sort of leakage to the D+ wire.

You could also try pulling the battery lamp from the cluster and see if the issue goes away. You'll still get exciter voltage through the diodes of the other lamps when starting, so it should be charging, but you won't have a warning if it's not.
 
It looks like you're tapped into power for the passenger side power windows. This is a poor place to use - from the ignition switch, it goes through a fuse and through the main power window relay. Try moving the switched +12v to MS3x connection to anything that's directly connected to the ignition switch -- see the fuse diagram on page 1 of the greenbook. (And those yellow or blue "vampire" tap blocks are awful and unreliable.)

With your power-window connection, the alternator D+ through the battery warning lamp may have just enough current to keep the power window relay energized when there are no other loads on the switched +12. This would keep MS3x energized. If you shift to reverse, to turn on the backup lights, when running with key off, does it stop?
 
bobxyz said:
Do your main power and relay connections match this diagram exactly? If not, please post your power/relay diagram.

From your original pictures, I noticed that the gas gauge drops, but doesn't go to zero, with key off. This implies that there is still voltage at the cluster, maybe 7volts as a guess. I don't know if running your alternator originally without a proper big ground wire could have damaged it. I'd pull the alternator and get it tested at an auto shop to see if there is some sort of leakage to the D+ wire.

You could also try pulling the battery lamp from the cluster and see if the issue goes away. You'll still get exciter voltage through the diodes of the other lamps when starting, so it should be charging, but you won't have a warning if it's not.
Click to expand...

Yes my wiring scheme is like the diagram you posted.

I pulled the battery bulb and it solved the problem.

bobxyz said:
With your power-window connection, the alternator D+ through the battery warning lamp may have just enough current to keep the power window relay energized when there are no other loads on the switched +12. This would keep MS3x energized. If you shift to reverse, to turn on the backup lights, when running with key off, does it stop?
Click to expand...

Will try that an report back.
 
Your main MS3x relays are not connected directly to the ignition switch, but are instead connected to the power window relay. This allows the alternator, through the battery warning light, to supply enough back power to keep the power window relay energized after turning the key off. I'll post a picture tonight showing the back-power path and why your MS3x won't shut off.

If you move your main MS3x relays to the actual ignition switch wiring (as shown in the MS3x diagram), you'll have a total of 3 relays off the ignition switch. This should cause a large enough load that the battery lamp can't back power all 3 relays and thus the engine will shut off correctly.
 
Good to see you got the main issue firgured out. I would to look for an open right side terminal on fuse 12 or 13. They are usually the fuses used for turning on stuff like the ignition and cluster. There are usually open terminals on the right side of the fuse box for you to tap into.

Also if those are full then the lower fuses like 14 and down are also usually igntion key switched and even more likely to have an open right side terminal.
 
Here's a diagram of what's going on with your wiring:

back-power-ms-from-alt1.png


When the key (C on left) is shut off, the engine is still running and the alternator spinning. The alternator back-powers the switched +12v wires (ignition switch pin 15) through the console battery warning lamp (B). As a guess, this provides maybe 7volts instead of the normal 12 to 13 volts on switched +12v wires. This is just enough to keep the main power window relay (A in middle) energized. Since you've tapped off of window power, instead of direct from the ignition switch, the MS3x stays powered up and the engine continues to run.

With the key out but still running, if you add any additional load to the switched +12v wires, it will be too much for the battery warning lamp to supply. This will cause the power window relay to open and MS3x to lose power. I think turning on the backup lights or turn signals will load down the switched +12v and cause the engine to stop.

In a normal LH2.4 setup, this isn't an issue because there is much more than a single relay on the switched +12v wire, including ECU/EZK, coil, injectors, etc. One wimpy little dashboard lamp can't back power that big of a load.
 
Time flies. I realized i never updated you guys about my problem, because the car didn't drive too much, house, baby, you know the drill.

To BOBXYZ : you are a genius. While i do believe i got a very logical mind, i never would have thought about this issue. Your drawing is 100% true.

I had the alternator fail on me a few weeks ago, so i changed it for a new one. Put all new bulbs in my dash (for other reason) and boom : again, engine wouldn't stop. I forgot i had removed the battery bulb as a temporary fix 2 years ago.

It would stall, if the key was off, AND i put it in reverse. This is when i thought : damn that guy is smart. Without even seeing the car in flesh.

AAAAAANYWAY : turned out that it was just a user mistake, as usual :

the D+ wire (on alt side) had a spade connector (maybe i changed it at some point) so i thought it would go on the spare spade on the alt, which happened to be a B+ and not a D+. No wonder the battery light went on when key off.
Cut the spade connector and wired it on D+, the real one.
At the same time, i wired my megasquirt main relay on a spare switched +12V supply on the OEM fuse box.
Guess what : all is well in the world now.
14v idling, and the usual 1.65bar boost with a big ****in smile on my face. God i love this car.

Thank you all for your great help.
 
You must log in or register to reply here.
Back
Top