Starting a little harder.

[psaboic]

1983 300D began starting a little harder recently. Only happens if the engine is stone cold or has sat for about 2 hours. Warm starts are fine. Sounds like classic glow plugs right? I thought so too. All the glow plugs read .4 ohms, the glow plug wires read .01 ohms. I have battery voltage at the glow plug relay and on both sides of the strip fuse. Turn the car to glow and all 5 plugs have battery voltage to them until the relay times out, so it seems the glow plug system is fine. No air in the fuel lines either. The only thing I think it could be is the battery. Battery still holds a charge of about 12.3 volts, and a little over 13.5 or so with the alternator running. However the battery is a 75 Month NAPA battery that according to the sticker has been in the car for roughly 100 months (Jan 2011). Suggestions?

[Shern]

When I had that issue, turned out I was getting some leak back somewhere in the fuel system. Try pumping the primer like 10-20 times before starting. If that helps, find the air ingress. Mine was very subtle and came down to a crush washer near the secondary fuel filter.

[psaboic]

Worth a shot......thanks

[INSIDIOUS]

Or try a cold start on a charger

[gregp1962]

When mine was starting slow, it turned out the starter was turning slow. The problem was, it was almost impossible to diagnose. I blindly replaced the starter. All was well after that.

Maybe take it in to O' Reilley or Autozone and have them test the amp draw.

[psaboic]

Worth a shot....thanks

[Diseasel300]

An 8 year old battery has been on borrowed time for a while now. You'd be time and probably money ahead to replace it just on principle, but you could have it load tested at an auto parts store. A fully charged battery should be ~12.6V. If the battery is tired, you can expect slow cranking.

[psaboic]

Yeah, I know......8 years is great for a battery. I'm going to check it with a meter in the morning and see what voltage I have after sitting over night, and then what it is with the glow plugs heating.

[psaboic]

Ok, as promised, I checked the voltage on the battery this morning after sitting all night, temps in the mid 40s. Battery read out at 12.65 volts. Turned the key on to activate the glow plugs and it predictably dropped to 11.32. Battery is still pretty good voltage-wise, but is most likely getting tired.

[barry12345]

Get a free check for current delivery at many auto parts stores. Battery may indeed be tired but you want to make sure it is before replacement. Eight years is suspicious but not conclusive. Or borrow a load tester.

[HuskyMan]

I'm having the same issue. When the battery has been on the charger, the car fires right up. After a few days off the charger I can tell the starter is turning somewhat slower......which means time for a new battery......


Our cars eat parts parts and more parts, it is just the nature of the beast....

[dieselworks]

My 1985 300sd began having starting problems. My battery was 6 years old and I didn't drive it every day. Checked voltage and it was a little over 12 volts.
But a fresh battery will charge to around 14.6 volts.
When my battery got tired I started to put it on a charger and had good results but knew it was time to get a new battery. I did and when I put it on the charger it had 14.6 volts.
My experience is when the voltage is around 12 volts it's time to get a new battery.

Sent from my SM-G900I using Tapatalk

[barry12345]

Originally Posted by dieselworks

My 1985 300sd began having starting problems. My battery was 6 years old and I didn't drive it every day. Checked voltage and it was a little over 12 volts.
But a fresh battery will charge to around 14.6 volts.
When my battery got tired I started to put it on a charger and had good results but knew it was time to get a new battery. I did and when I put it on the charger it had 14.6 volts.
My experience is when the voltage is around 12 volts it's time to get a new battery.

Sent from my SM-G900I using Tapatalk

While on a charger be it a external one or the cars alternator. Unless the battery has a shorted cell the reading is not too signifigant. A normal battery will read about 12.6-12.7 after sitting for some hours. This is just a superficial test though. The ability to deliver current is far more important.

This is why a load test is so important. Any car this old or at any age can develop bad circuit connections that can mimic a bad battery.

It varies a little with temperature but in general about 12.7 is considered a fully charged battery. It just may have had the storage ability reduced by age or has too much internal resistance when asked to deliver a lot of current.

This is what determines how good the battery really is. Always check the internal fluid level before rushing to judgement. An alternator that is over charging will boil off the fluid. Use distilled water to top it back up.

I have had very poor overall usable battery lifespans on cars not used frequently enough. I have never really looked for information. If batteries last longer on average in one temperate area of the country versus another.

I have heard that batteries do not like a lot of heat. True or not I do not know.

There is not much sense taking a reading right after a battery charge either by an alternator or external charge. You will only read what is described as a surface charge that will bleed off after sitting awhile.

[sloride]

I realize this was a month old thread, but have the valves been adjusted? To tight leaks compression and needs more cranking to build the heat needed to start. Sounds like the battery may be the issue, just my $0.02.