98 S70 electrical issues Topic is solved

[shegarty]

Morning all - I think the alternator on my 98 S70 took a dump on me this morning on the way to work. Luckily, I was able to limp it back home and take another vehicle.

Background - I have owned the car for 10+ years now and do all my own maintenance. I have noticed over this time that the voltage seems to dip when a high draw accessory (blower fan, headlights etc) comes online but then quickly returns to normal range (13.2-13.7V). It also does this on startup but returns to normal after 5-10 seconds. I replaced the battery about 5 years ago with a walmart house brand and only got about two years out of it, the next replacement lasted about 3 years and I just swapped it out a month ago. More recently (last week), I had an incident where the "flashing arrow of death" came and the transmission seemed to be in winter mode (very slow from a standing start almost like it was in second gear). This was cleared by turning off the car and restarting it. I scanned it when I got home and didn't find any stored codes. I didn't have a voltmeter installed yet but grabbed one that fits in the lighter socket that I've been using to monitor it since then. On the way to work today it was fine until I attempted to merge onto the highway, then the flashing arrow came on again and the voltage dropped to below 12V. I limped it to the first exit and then back home again and most of the time there was no charging at all and the voltage was steady around 11.9-12.1V. There were a couple of instances where the voltage appeared to jump up again to 13.3V or so but then dropped back down again.

I am assuming that the charging system is faulty but I haven't had a chance to see if the accessory belt is slipping. I have already replaced both the main wire between the starter and the battery and the B+ cable to the main fuse box with quality welding cable with soldered ends. I am assuming that the alternator (likely OE) has failed and as such have a couple of questions. First, do these version have an external voltage regulator like the older redblock engines? Second, if I have to replace the whole unit what brands/remans should I stay away from?

Thanks folks

[scot850]

If the bearings are good, typically it is the replaceable voltage regulator that has worm out. It seems to be hard to find voltage regulators in Canada for some reason, probably as the sellers would rather sell you a whole unit. Only place I could find them was FCP Euro or EBay. Bosch only.

Re-built/remanufactured alternators these days are a crap shoot, Even 'new' builds are poor. Maybe worth seeing if the is a reputable rebuilder in your area. I even read variable comments on Bosch re-manufactured alternators these days.

Good luck with the fix.

Neil.

[shegarty]

I've heard this about rebuilds in general. I've been doing some research this morning and have found the iPd option but I don't think FCP has the right one in stock. I'm also leaning towards the regulator as there has been no other issues (ie. bearing squeak). I might get lucky and find a used one in my spares pile when I get home but if not I'll pull the trigger on one of the US suppliers and I should get it within a week or so. Thanks for the insights.

[foggydogg]

Another possible issue might be grounds, our old P80s like to get crusty in those areas.
I put a regulator/brush pack on an XC at the 275k mark, still doing well at 325k when I parked it under the pin oak. I swapped a used one into another car, also did fine. They are pretty durable units. I have no experience with rebuilds but as always, avoid anything that says Cardone.

[shegarty]

Another possible issue might be grounds, our old P80s like to get crusty in those areas.

I will be checking these as well - acted up today in very wet conditions but then it happened before when it was dry. Are there any easy to read wiring diagrams for ground locations?

[misha]

Did you performed a voltage drop test?
That will tell you everything you need to know.

I assume that you checked battery voltage on battery terminals.

When car starts to act up again...measure voltage output on battery terminals and also directly on alternator(+ on b+ and - on alternator housing).
If alternator shows good output...then your rebuild cables or crimping are not good...or battery is bad(again).
Cig.lighter socket will ALWAYS show lower reading than it actually is.

[misha]

Did you performed a voltage drop test?
That will tell you everything you need to know.

I assume that you checked battery voltage on battery terminals.

When car starts to act up again...measure voltage output on battery terminals and also directly on alternator(+ on b+ and - on alternator housing).
If alternator shows good output...then your rebuild cables or crimping are not good...or battery is bad(again).
Cig.lighter socket will ALWAYS show lower reading than it actually is.

[shegarty]

Did you performed a voltage drop test?
That will tell you everything you need to know.

I assume that you checked battery voltage on battery terminals.

I plan to do this tonight or within the next couple of days - the only cable that I haven't replaced is the B+ from the alternator to the starter

[shegarty]

Cig.lighter socket will ALWAYS show lower reading than it actually is.

I have been running the lighter socket one just to monitor how things have been acting since replacing the battery (which load tested bad). My thoughts are that the alternator has been undercharging for a while now which cause the battery to go bad.

[jmartin919]

Is the + cable within a few inches from the battery hot to the touch after driving?