From strange bad smell to regulator problem

[brd]

Well... started having a strange smell inside the car recently... quite strong, even though good weather means all windows open and fan on. More unpleasant that anything really. Couldn't figure it out. It had a sorta familiarish smell to it, little rotten, little oily... but couldn't pin it down.
Started checking for oil leaks and possible drips onto the heat exchangers... nope... all looked pretty good there. Then I thought about the ventilation system - which I had recently got and put back in the car - the last guy had hacked out allot of stuff and left a wiring disaster (part of another story: Road trip in a 930). I was wondering if there was gunk or something in the ducting from age and if this could be causing the smell. So I took apart the fan unit.. easy enough job.. but no, pretty clean and definitely not the issue. Then I started thinking about the hot air routing (I haven't got the back part connected up.. and may not actually do it as it doesn't get so cold here in the south of France along the coast)... and was wondering how I could check it.

Then the other day I noticed the car was lazy starting... battery wasn't good. Strange, as it is only a few months old. This morning going to work, it barely started (its a daily driver)... even though I had stuck a battery charger on it over night a few days ago. I have a spare, so chucked that in the front with jumper cables just in case. Coming home, it JUST about fired so I decided to start checking the charging circuit... There was a funny air releasing noise from the area when I started removing the carpet and opening the smugglers lid (I have the battery there with an isolator switch under the dash for security)... but thought it was the fuel tank or something as it's hot out.
I stuck a multi-meter over the battery and saw 13.6V with engine off - bit high I was thinking. Then started the car and it was 16V on tickover! Not good. I took the battery out and it had lost its straight lines a bit... sides were bulging out slightly... and the hissing noise was from the battery itself.

So... regulator must be knackered I was thinking. So, a bit of Pelicaning and I see that the regulator is not on the back of the alternator on 81SC engines (SC engine in a 1970 T). Strange.. I didn't see any regulator on the left of the engine bay. And it starts to make sense. The previous guy must have bypassed where the regulator was (some strange botch job cabling where the regular would be).

So... strange smell was probably the vapours from the battery acid boiling and I was lucky it didn't burst and leave a mess in the smugglers box!

Next up is a good check of how the charging circuit should be and sort it out. I have all the wiring diagrams I can find, so ok there. But if any of you have pictures of 81SC (or similar config) rear left side in engine bay would help - showing relays and cabling... much obliged!
At the moment I only have one relay, the rear window defroster relay and the CDI.

And you know.... I bought the car so that if I ever had to work on what I use for transport, that I would enjoy it ... and I most definitely do. I always get the sense that it is WORTH working on because of what it is.

Thanks.

[Peter Zimmermann]

Originally Posted by brd

Well... started having a strange smell inside the car recently... quite strong, even though good weather means all windows open and fan on. More unpleasant that anything really. Couldn't figure it out. It had a sorta familiarish smell to it, little rotten, little oily... but couldn't pin it down.
Started checking for oil leaks and possible drips onto the heat exchangers... nope... all looked pretty good there. Then I thought about the ventilation system - which I had recently got and put back in the car - the last guy had hacked out allot of stuff and left a wiring disaster (part of another story: Road trip in a 930). I was wondering if there was gunk or something in the ducting from age and if this could be causing the smell. So I took apart the fan unit.. easy enough job.. but no, pretty clean and definitely not the issue. Then I started thinking about the hot air routing (I haven't got the back part connected up.. and may not actually do it as it doesn't get so cold here in the south of France along the coast)... and was wondering how I could check it.

Then the other day I noticed the car was lazy starting... battery wasn't good. Strange, as it is only a few months old. This morning going to work, it barely started (its a daily driver)... even though I had stuck a battery charger on it over night a few days ago. I have a spare, so chucked that in the front with jumper cables just in case. Coming home, it JUST about fired so I decided to start checking the charging circuit... There was a funny air releasing noise from the area when I started removing the carpet and opening the smugglers lid (I have the battery there with an isolator switch under the dash for security)... but thought it was the fuel tank or something as it's hot out.
I stuck a multi-meter over the battery and saw 13.6V with engine off - bit high I was thinking. Then started the car and it was 16V on tickover! Not good. I took the battery out and it had lost its straight lines a bit... sides were bulging out slightly... and the hissing noise was from the battery itself.

So... regulator must be knackered I was thinking. So, a bit of Pelicaning and I see that the regulator is not on the back of the alternator on 81SC engines (SC engine in a 1970 T). Strange.. I didn't see any regulator on the left of the engine bay. And it starts to make sense. The previous guy must have bypassed where the regulator was (some strange botch job cabling where the regular would be).

So... strange smell was probably the vapours from the battery acid boiling and I was lucky it didn't burst and leave a mess in the smugglers box!

Next up is a good check of how the charging circuit should be and sort it out. I have all the wiring diagrams I can find, so ok there. But if any of you have pictures of 81SC (or similar config) rear left side in engine bay would help - showing relays and cabling... much obliged!
At the moment I only have one relay, the rear window defroster relay and the CDI.

And you know.... I bought the car so that if I ever had to work on what I use for transport, that I would enjoy it ... and I most definitely do. I always get the sense that it is WORTH working on because of what it is.

Thanks.

If the fan pulley nut is 22mm (check with a wrench or caliper) the alternator requires an external regulator. If the nut is 24mm the alternator has been upgraded (a common practice) to an alternator that uses an internal regulator. That alt/reg has failed, and allowed the battery to overcharge and boil itself dry, which produced your rotten egg smell. The early alt will also have a flat-tipped shaft (seen in the center of the fan belt pulley), while the '82> alternator w/regulator will have a place to insert a hex wrench.

[brd]

Ah... very useful that!! And an easy check to do... so easy in fact that I'll just grab two sockets and go have a lookey see right now.

Thanks.

[goat]

Had the same experience about a year ago.
Boiled over an optima battery, and made quite a mess. If your battery boiled over check to make sure acid did not spill down onto your framework.

[darrin]

I'd strongly recommend removing the battery and carefully examining the area below the battery and under the car for signs of acid leakage. The rotten egg smell you had came from the battery boiling over and when this happened to my carrera when I first received it, I found that the boiling acid had done a number on my battery box and the crossmember under the car. Hopefully, yours has been caught early enough and/or your battery is vented under the car (mine was not) and some good cleaning with baking soda, etc. will get yours back as good as new.

[tcar]

Exactly the same thing happened to me w/ a 6 month old Optima last fall.

Bad smell for a couple weeks (don't drive it every day). Didn't know what it was.

Gauges started jumping all over, wipers started and stopped on their own and it died.

Optima battery case was 'soft' like jello.

Regulator gone.

Get it fixed NOW.

Your electrical system will only take 19 Volts for so long before you have a FIRE or melted wires somewhere or everywhere.

Know someone that had it happen and had to replace the ENTIRE wire harness. $7k dollars.

BTW, Optima gave me a new battery on warranty.

[brd]

OK... will do.

I checked and it appears to be the upgrade that you mentioned Peter. So I'll have to go in behind.

Sparse fuse/relay area


Overall view with 24mm socket on nut for size


24mm nut with Hex centre (thanks Peter)


Now I guess I need the rear mounted voltage regulator. Could I assume that with the alternator putting out 16V on tickover (with blown regulator), that the alternator itself should be fine?

Thanks for your help!

[tcar]

The early SC's had v. regulators on the console (LR) as shown, but if it's ever been replaced, you probably have the integral VR.

My regulator on my '80 was still sitting there on the console just like yours, but no wires to it. Check it.

I Think they switched to integral V.R.'s in '81 or '82. Virtually all have been replaced by now.

If the regulator is integral, so you almost have to get a rebuilt alternator.

[Peter Zimmermann]

I would locate an expert to rebuild the alternator (something about slip rings and diodes), including, of course, a new voltage regulator. The regulators are available as the small original, or a slightly over sized one, your re-builder should know that. Use the bigger VR, and then cut/modify as necessary the gray-colored air guide that fits over the back of the alternator to clear the new VR. The small VR will be silver, the big VR will be black.

[brd]

So an alternator rebuild is necessary?
Would just replacing the voltage regulator be all thats needed?

I don't mind getting the alternator done, if necessary... but if it is clearly charging, don't know why it would need to be done too... but you guys prob know more than me about these things.

Thanks.

[mike the snake]

I had a VW van that the alternator burnt up while I was driving, kind of smelled like rotten pumpkins. Not sure whether it was a regulator that caused it, but the Alt. windings have a certain smell when burning.

I'd definitely check out both the regulator and alternator, and the battery as well.