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  #1  
Old 02-01-2013, 01:15 PM
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Question Persistent cold start problem - now below -11 C / 12 F

Story ('85 300d, 105k miles, Rotella synthetic, car runs very well and started last winter without effort):

- October - replaced glowplugs with Bosch duraterms. Strictly a preventative -- old plugs of unknown age.

- Late November - intermittent 'no-glow' (no glow light illuminating, no relay engagement. Eventually found retaining nuts were loose on 3 of 5 plugs. Tightened nuts, problem seemed gone.

- January - onset of cold snap (-18 C / ~ -1 F) resulted in no start when car left for day at work, no block heater etc. No fuel getting to injectors. Ran through Diesel 911 additive to remove any moisture in fuel, replaced fuel filters after. Tightened clamps on fuel lines (found one very loose, assumed this contributed to fuel gelling). Never had time to test this out properly as extreme cold ensued (-26 C / - 15 F) so car was either left running (at work) or plugged in. Fired right up in mornings, after two glows, at home with block heater.

- Yesterday morning - only -5 C / 23 F, car not plugged in, was very surprised it would not fire after the first glow cycles. After two cycles, ran unevenly once started, like the glowplugs were tired.

- Last night - came out yesterday from work, -11 C / 12 F, was stunned when car took a lot of cranking to fire. Again typical of what I would expect from weak plugs, one or two pots fired first but had to keep starter engaged to get the rest going.

Checked when I arrived at work and I have 12v at the plugs with the relay engaged. Don't carry an OHM meter in the car.

Right now I am leaning toward replacing the glowplugs over the weekend.

What am I missing here?

Thx

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Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22
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  #2  
Old 02-01-2013, 01:38 PM
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Could be tight valves....valve adjustment is probably needed if it has been done recently.
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Old 02-01-2013, 01:48 PM
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Could be a single bad plug. My daughter's 84SD with a relatively new engine won't fire below about 20 degrees with one plug out. I'd also use PowerService anti-gel if temperatures were consistently that low.
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1977 300d 70k--sold 08
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1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
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1979 300SD 122k--sold 2/11
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1993 GMC Sierra 6.5 TD 4x4
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  #4  
Old 02-01-2013, 02:26 PM
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Quote:
Could be tight valves....valve adjustment is probably needed if it has been done recently.
Valves were adjusted in August. Usually tight valves will show up at even higher temps, in my experience.

Quote:
Could be a single bad plug. My daughter's 84SD with a relatively new engine won't fire below about 20 degrees with one plug out. I'd also use PowerService anti-gel if temperatures were consistently that low.
I had not thought of the single bad plug angle, I was banging my head on how an entire set of plugs could be no good. Will check them with a meter tomorrow when cold.

The Diesel 911 I used is the PowerService product they sell here for ungelling fuel (you can get an even stronger one from heavy equipment dealers that guarantees complete degel in 20 minutes). I guess I could add more now.

I suppose I could try filling up somewhere else too, though I would wonder how the station I am using could have that much water in their diesel tank. They're relatively busy, and installed new tanks six months ago.
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Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22
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  #5  
Old 02-01-2013, 03:29 PM
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Do not replace the glow plugs again since they are recent. The problem is elsewhere. MY guess: air in fuel.
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  #6  
Old 02-01-2013, 03:56 PM
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Quote:
Originally Posted by funola View Post
Do not replace the glow plugs again since they are recent. The problem is elsewhere. MY guess: air in fuel.
I would be willing to work with that, but where do I look?

I have tightened every fuel line clamp under the hood. There isn't any smell of diesel anywhere nor signs of a seep. The cigar hose is brand new. The return lines were done at the same time as the glowplugs.

The primer pump is the new style. Do they leak with age, like the old style?

Why would it start fine, with the block heater, if the issue is air in the lines? I would expect it to still need more cranking.
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Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22

Last edited by Zacharias; 02-01-2013 at 04:16 PM.
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  #7  
Old 02-01-2013, 04:36 PM
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Quote:
Originally Posted by Zacharias View Post
I would be willing to work with that, but where do I look?

I have tightened every fuel line clamp under the hood. There isn't any smell of diesel anywhere nor signs of a seep. The cigar hose is brand new. The return lines were done at the same time as the glowplugs.

The primer pump is the new style. Do they leak with age, like the old style?

Why would it start fine, with the block heater, if the issue is air in the lines? I would expect it to still need more cranking.
Do you have a clear line in line with the cigar hose? If you have solid fuel there at all times (including when the engine is off) then you have no air problems. If you see any bubbles after the engine starts you have air in fuel.
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  #8  
Old 02-01-2013, 05:59 PM
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Quote:
Originally Posted by Zacharias View Post
Don't carry an OHM meter in the car.
But, you do have one at home.

So, check all the plugs and see if any good info comes from the resistance check.

If not, the requirement from Roy is to pull all five and glow them in a vice to see what you have.
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  #9  
Old 02-01-2013, 06:04 PM
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Last cause scenario it may be time for new injectors....perhaps one or two aren't spraying correctly.
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  #10  
Old 02-02-2013, 02:40 PM
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Are your glow plugs getting power? That is an easy test even without more than test light.
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  #11  
Old 02-02-2013, 03:03 PM
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OHM test

Checked with the OHM meter today.

Number 3 gives a different reading each time it's checked, between 4.2 and 8.6.

The other four are 1.1.

What I don't get, is how in this parallel system, one defective plug (other than #1) would effect the glow cycle like that. Can someone explain in 'for dummies' terms?

Just for insurance, I also dumped in more Diesel911 and filled up at the station I used last winter.

Thx
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Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22
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  #12  
Old 02-02-2013, 03:20 PM
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Quote:
Originally Posted by Zacharias View Post
Checked with the OHM meter today.

Number 3 gives a different reading each time it's checked, between 4.2 and 8.6.

The other four are 1.1.

What I don't get, is how in this parallel system, one defective plug (other than #1) would effect the glow cycle like that. Can someone explain in 'for dummies' terms?

Just for insurance, I also dumped in more Diesel911 and filled up at the station I used last winter.

Thx
The 1.1 ohm reading itself indicates a questionable glow plug. As for the inconsistencies, I'd question the quality of the battery powering the meter. Particularly with DVOM's, a weak battery will cause some pretty strange readings.
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  #13  
Old 02-02-2013, 03:23 PM
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Quote:
Originally Posted by Zacharias View Post
Checked with the OHM meter today.

Number 3 gives a different reading each time it's checked, between 4.2 and 8.6.

The other four are 1.1.

What I don't get, is how in this parallel system, one defective plug (other than #1) would effect the glow cycle like that. Can someone explain in 'for dummies' terms?

Just for insurance, I also dumped in more Diesel911 and filled up at the station I used last winter.

Thx
Clearly, #3 is toast.

Change #3 and see if the capability to start is improved.

If not, the readings of 1.1 ohms are at the very bottom end of acceptability and it might be time to pull them all and give them a bench test.
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  #14  
Old 02-02-2013, 09:40 PM
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You did not mention if you cleaned the Carbon out of the Glow Plug holes before you installed the New ones?
Some Members have said pulling the Plugs and cleaning the Carbon out made starting easier.

I had a Glow Plug that Ohmed out OK but when I tested it over the Battery Terminals it got hottest in the Middle instead of at the Tip where it is supposed to be hottest. That meant the Heat was heating up the Cylinder Head instead of the Air in the Prechamber.
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Persistent cold start problem - now below -11 C / 12 F-glow-plug-test-bad-jan-13.jpg  
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  #15  
Old 02-02-2013, 10:13 PM
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Did you unplug the harness from the relay when ohm testing? If you don't you can get funky readings.
I don't know now and why a single bad plug causes a no start condition. I was surprised when I discovered it happening on my daughter's SD. It happened at least twice on that car.

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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
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