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#1
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BAttery reads fine but won't start
I replaced the battery in my 300D recently and it is fine. The starter turns perfectly. I replaced the voltage regulator yesterday.
For some reason the car needs a jump to start and a lot of times it needs a very long charge to jump. In the mornings it needs a long charge but once I have it up and running it will start fine for up to about 30 or 40 minutes and after it has been sitting longer than that I need to jump it off. Once I have it running the battery reads fine. The alternator is reading a little low but not drastically low. So ya'll think it could be a connection or the laternotor or what?
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http://www.libertyagrifuels.com 1984 300D Turbo 1980 300SD Sold 1983 300TD Sold Dagger 16 ft. Legend Canoe (for the weekends) Marin Northside Trail Mtn. Bike |
#2
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What is it reading? Belts tight? Probably a short in the system somewhere.
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http://superturbodiesel.com/images/sig.04.10.jpg 1995 E420 Schwarz 1995 E300 Weiss #1987 300D Sturmmachine #1991 300D Nearly Perfect #1994 E320 Cabriolet #1995 E320 Touring #1985 300D Sedan OBK #42 |
#3
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As an experiment, try disconnecting the battery negative cable overnight. If you have a "leak" somewhere in the electrical system, that will stop it from draining the battery. While you're in there, make some measurements so that we have numbers for the charging system rather than "fine." If the alternator voltage is "low" it may not be delivering any current to charge the battery.
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"Buster" in the '95 Our all-Diesel family 1996 E300D (W210) . .338,000 miles Wife's car 2005 E320 CDI . . 113,000 miles My car Santa Rosa population 176,762 (2022) Total. . . . . . . . . . . . 627,762 "Oh lord won't you buy me a Mercedes Benz." -- Janis Joplin, October 1, 1970 |
#4
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when this happened to me, the first thing i did was check for corrosion at the battery terminals and cable, have you done this?
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#5
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have you checked the belt's tension? alternator needs very good belts, and your battery is not fine if it will not start the car.
in the morning before you touch the key, get a good digital voltmeter, and check the battery voltage. it needs to read 12.75 or above. if not it's low. and weak due to it's discharge state. also, when the car is running, the battery voltage needs to be 13.5 or higher at idle, and it should go to 14.1 when revved.
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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread "as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do! My drivers: 1987 190D 2.5Turbo 1987 190D 2.5Turbo 1987 190D 2.5-5SPEED!!! 1987 300TD 1987 300TD 1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere! |
#6
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Disconnect the ground wire from the battery, put it on a charger overnight.
In the morning put your multimeter on the battery and crank. How badly does voltage sag during cranking? Its entirely possible to get sold a bad battery...
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Sadly Benz-less |
#7
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If the battery checks out fine, you may want to check the starter draw with an inductive ammeter. Could be a bad starter.
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1977 300d 70k--sold 08 1985 300TD 185k+ 1984 307d 126k--sold 8/03 1985 409d 65k--sold 06 1984 300SD 315k--daughter's car 1979 300SD 122k--sold 2/11 1999 Fuso FG Expedition Camper 1993 GMC Sierra 6.5 TD 4x4 1982 Bluebird Wanderlodge CAT 3208--Sold 2/13 |
#8
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I would also check for a voltage "leak", using an amp meter and test it at all fuses to see where the power draw is.
I left the rear dome light on when I first got my car, because I did not know that the switch worked independently of the rear doors. Also I did not notice it until I went out when it was dark out. Then I saw the light...
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RRGrassi 70's Southern Pacific #5608 Fairmont A-4 MOW car 13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete. 91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K 90 Dodge D250 5.9 Cummins/5 speed. 400K |
#9
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Some of your time frames indicate the glow plug relay may not be releasing. Just use a test light or voltage meter to read the glow plugs. If voltage is present after the car has started the relay is staying closed.
Some of your information indicates a pretty heavy drain. Todays car batteries really do not appreciate being drained down. It tends to damage them in my experience if it is repeated multiple times. Car batteries are not deep discharge cycle designs. Since the battery is under warranty being a recent battery. Have it properly checked out just before the 100 percent replacement portion of the warranty expires. There is also a slight chance your new battery is defective and will not hold a charge. It will accept one just not hold it. This is not as likely as an external to the battery drain situation. When you say the alternator seems to be a little low on output I assume you are reading the battery voltage with engine running. This could be consistant with the glow relay being constantly on as well. |
#10
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I have lots of experience with batteries being drained, from my spare cars sitting. I can tell you if you completely drain a battery 5 or 6 times forget it. It's toast. I don't remember the electrochemical reason why but the battery just gives up if you drain it too many times.
I had an old Porsche that I let sit too much, and over 6 years I probably had to put 5 brand-new batteries in it 'cause of that.
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'81 300CD - 180K, cannot be killed by any conventional means '99 Ford Escort - good MPG |
#11
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Quote:
Drain the battery for storage. When you want it back in service dump the electrolyte back in. The battery will return to the same charge state as it was prior to dumping the fluid. American naval forces use this method to store their lead acid batteries for as long as 15 years. I know of nothing else even the effort of using regulated trickle chargers that works. I too have lost far too many car batteries in the past. |
#12
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Quote:
FYI, you'll need to store the electroyte or replace with fresh full-strength sulphuric acid to reconstitute. The charge is stored partly in the acidity level of the electrolyte -- pure water = dead battery.
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'83 300DTurbo http://badges.fuelly.com/images/smallsig-us/318559.png Broadband: more lies faster. |
#13
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check your neutral safety switch if you determine that you have a good battery. a bad neutral safety switch will cause the car not to start.
Also check to make sure you are getting fuel. Check your starter too.
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1986 300SDL, 211K,Dealership serviced its whole life 1991 190E 2.6(120k) 1983 300D(300k) 1977 300D(211k) |
#14
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Quote:
Needless to say best to put the electroyle under lock and key. At least use safety appliances like a full face shield and gloves etc when inverting the battery. |
#15
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Thanks for all the help. I am an extreme novice to testing electrical hookups but I think that there is enough info for me to figure things out here.
My main question is this. What setting does my standard volt meter need to be on. IT has like 19 different settings. It is the one withe the turn dial. I got it Auto Zone for like $17. Thanks again Guys, Zack
__________________
http://www.libertyagrifuels.com 1984 300D Turbo 1980 300SD Sold 1983 300TD Sold Dagger 16 ft. Legend Canoe (for the weekends) Marin Northside Trail Mtn. Bike |
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