99 S320 112k

Have had parasitic drain for years I could not locate. Installed neg. grnd. switch to deal with it (what a pain of a solution). Finally battery died and replaced with new MBZ white. Now alternator is dead and so I bought a rebuilt.

Now with the alternator out, I put a meter across the negative side of the new battery, and I am getting a drain of only .120 on the milliamp scale. I pulled every fuse in the engine compartment and in the trunk and the .120 never dropped. Seems to me it used to be much higher drain.

Questions:

1) Is it possible that the parasitic drain for all this time was in the old alternator or old battery? Can an alternator drain a battery in the off position?
2) Is there another fuse block I am missing?

3) Is a .120 drain in the realm of normal?

4) The pulley on the rebuilt alternator I bought is shorter requiring that I switch the old for new prior to install. Any help with how I get the pulley nuts off without damaging the new unit? Or where I might take it to have this done?

Thanks for any help,

Chris

Oops, that info I gave was wrong, in case you or others saw it. I misread. That seems way too low, (initially I thought it was too high)
Normal would be eh around 20-40ms or so. Check your scale on the meter. If it's 12ma, that would be still low, but would be OK.
Gilly

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AND now just noticed it's a 140 chassis, yeah .120ma is way too low, on a 140 chassis, even a S320, normally they run a bit higher than most other cars of the period, 40-50ma not unusual or a tad higher. Should be something way higher than a tenth of a milliamp, need a few digits AHEAD of that decimal, again I'd check the range on the meter.

Gilly

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solved #4) 20 bucks @ machine shop.

but I have a new #4 to replace it: Tricks to getting belt back on. It has the automatic tensioner.

I'm thinking it may be 120 ma- .12 amp

Chris

Do you have the trunk fooled into believing it's closed as you're measuring your drain? Not sure, but there may be control units that wont go to sleep with the trunk open, not to mention the courtesy light. Also, you will want the hood shut. 120ma I believe is too much. Yes it could have been caused by a bad alternator, but you now have that amount of draw with the alt. removed, correct? Do you have the key out of the switch when you measure? How long is the 120ma present?

After a good long period (30 min) the draw dropped from 120 to 100 ma, but no lower. Again, pulling fuses one at a time, no fuse drops it any lower, using the two fuse boxes, trunk and engine compartment.

The trunk is open to measure the draw but the lights have been removed, no key, battery disconnected on neg side with a cut off switch and measuring the draw across the two poles on the switch (in line on the negative cable).

The new alt. is on and I am still trying to figure out how to spring the auto tensioner enough to get the last pulley on. I figure the the little pulley that doesn't run anything directly above the alternator is the one to go for last?

Once I make the negative bridge with the meter, is it possible that something like the like the vacuum pump can do some drawing, though I don't hear anything?

Thank you, Chris

Need to figure out what the Ma is that it's drawing, it's getting very confusing. Remember 1000 Ma=1 amp. On a 140 you might expect it to be 40-50ish Ma. 100Ma is too high. A bulb left on, on the other hand, even like a glovebox light will be a couple amps, so 2000Ma or so, not 125Ma. (reading over 1000Ma you typical can find, a light is on or you'll notice something is still on, radio or whatever) Yes you do want to wait awhile with a 140 for all the control units to go beddy-bye, close up everything, get the trunk latch tripped so the car "thinks" the trunk is closed and locked, then "sneak" the neg cable off with the ammeter inline like you have been doing, and wait a good 1/2 hour for everything to go into sleep mode, see what it is after that. Oh before diconnecting the neg cable you even want to lock the doors, you can leave a window open though, just in case.
Gilly

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OK, the new alt. is in and putting out 14.2V at the battery, idling.

Everything is turned off, car locked, battery unhooked on neg side, trunk open but fooled closed, hood closed. Now waiting for an hour.

Right now, the meter reads .110 0n ma; 1.1 on micro amp; and .011 on 10A scales DC, 12.91 V. I'm not sure what that is but it is a pretty decent meter (Mac Tools M710). I'm still thinking it is 110 ma.

Chris

That's what I'm getting at-take a screwdriver and trip the trunk latch, wait a while and see if that 100ma dissipates. Try to remember not to slam the trunk shut before you again open the latch.

Waited an hour and....you guessed it, Murphy's Law......instead of dissapating the drain has now INCREASED ......to .130-.140 must be right in the middle, vascilillates back and forth on the meter.

I guess i'll leave the battery connected overnight and see what the voltage drop will be over 12 hours.

Does anyone know anything about something called a "Priority Stop" that kills a battery circuit if it drops to 11.9v? Is 11.9v enough oomph to start an s320 in a warm climate?

Not happy with what the meter is telling you, can you check the fuses in the meter? What is the reading if the meter is set to the Ma scale and it's not connected to anything, does it go to zero or fluctuating? Can you also try setting it on a 1-10 amp scale and turning on the trunk light (that should be well under 10 amps), I want to see if the meter will show a couple amp draw or what's going on, with a relatively "healthy" car there is no way it can be reading this low. We're all just assuming what the drain is, by looking at what the meter is reading and what is assumed it MIGHT actually be, that's no way to test anything.
Gilly

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I have never heard of a priority stop. I don't have a silver bullet for your situation, but here are a couple of things I would do now: If you can get that car in a really dark place, look for something that glows. Make sure to check the glove box courtesy light and the vanity lights on back of the sun visors.Another thing to do is try touching all the relays and all the modules, radio amps, etc. you can find-even better would be to use an electronic non-contact thermometer and with either method, look for anything warmer than the it's surroundings. The last thing I can think of to suggest is, with your ampmeter showing that 100 or 140 ma draw, start unplugging relays. Remember when you're inside the car to trip the door latches; ditto the hood or trunk latches. Oh, I almost forgot-anything on that car that isn't stock is suspicious. Aftermarket stereos and anything plugged into the cigarette lighters deserve some attention. Sorry about all the generic advice, but I'm short on specifics on your car. I do hope you'll post when you get it figured out.

Still assuming on what the draw is. All the readings he is getting seem to indicate 1 microamp, not 100Ma, which we know is wrong. Plus even if it were a bulb staying lit, it would be a couple amps, way over what is being assumed (probably incorrectly) is 100Ma.
Gilly

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I agree the numbers are a little confusing. In post #8, the meter contradicts itself. It reads .110ma AND .110A. I believe he has 110ma (.110A) because I have seen autoranging multimeters do misleading things, and I sure don't buy that a 140 could ever have a .110ma drain. Also, the fact that he's always had this drain, and even installed a shutoff switch because of it lends credibility to the idea that there IS a parasitic drain. I'm not familiar with that meter-the Mac717 or whatever it was, but I always put my meter on the 10A scale to look for a drain, and I either see(depending on the situation) a whole number (or none), followed by a decimal point and 3 numbers to the right of the decimal. So on my meter, the 10A scale is straightforward to me. I agree that 110ma does not represent an incandescent bulb burning. I was thinking more of the vanity lights, but I'm not sure what they pull either. I would say that if a person put a 12-volt test light in series with either battery post, if there is indeed a 110ma draw, the bulb should glow, probably not very brightly, but .110ma probably wouldn't be visible. Getting a non-autoranging meter hooked up would also clear up some confusion!

you have something on somewhere? it could be the radio. somethings,s on start pulling fuses until you find what circuit it is on and then go from there, just my guess that is what i would do..