Long time reader, first time poster--but I know there are plenty of sagacious folks on this forum...

A cold snap just hit, and I forgot to plug in my block heater. Previously, my Benz didn't like to start when it was under about 40 degrees (had to hold the accelerator down after ignition to keep it running for 30 seconds) but now it's 15 out, and I can't get any ignition at all.

Battery is good, starter cranks fine (as far as I can tell). I plugged in my block heater about 6 hours ago, so that should've helped by now...?

I also tested the glow plugs and the relay--I'm getting 12v at the plugs, and the relay works fine. I even jerry-rigged a straight line from 12V+ to the glow plugs, bypassing the relay, and that didn't help either. The glow plug indicator light hasn't been working for a few days--I assumed it was a bad bulb, but maybe there's a systemic issue.

Finally, since I know fuel leaks can be an issue, I used the hand primer pump, and then loosened the bolt on injector 1 and cranked away--no luck. Frankly, I think less fuel was spurting after I tried this then when I used the same trick after replacing the fuel filter a few months ago.

I have not yet pulled the plugs...but again, it feels like 15F thanks to the wind, and the plugs check out electrically, so I'm hoping I don't have to.

Tips, pointers, complaints, or suggestions? Call our hotline at, er...here.

I wonder if you have some water in your fuel. Do you have any Diesel911 by any chance?

If the block heater is working (mine just died and that cold weather is coming to my area tomorrow... I feel your pain) it will take a good six hours to make much of a difference at those temps, in my experience.

When you used the primer pump, did it feel like you were pumping anything?

You didn't specify how long you glowed it for. At those temps I would leave it for at least two cycles (not just until the lamp goes out, the full 40 seconds or so).

The only two other things I can suggest:

- try putting a trouble light (incandescent bulb), or some other lamp with at least a 60w bulb, under the hood for a couple of hours, as close to the injection pump as possible.

- you can use WD40 sprayed into the intake while cranking as a starting aid. But I would wait to do that until after I tried it, giving the block heater and the lamp a bit of time to bring more heat under the hood.

Good luck with it....

__________________


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

Thanks, Zacharias.

I'll need to buy a light for that purpose, I'm afraid. I put half a bottle of Diesel Klean in the engine, but I don't have the actual 911 rescue fluid variety.

Edit: Yes, I could hear the liquid being pumped, I could see it in the secondary fuel filter, and I could hear it starting to return to the tank (I think).

Is my fuel gelled? Or is the fuel pump going the way of the buffalo?

I've been pluggin', so to speak, for a minimum of 2 cycles--sometimes 3--so I doubt it is a lack of glow plug convection (right term? eh, sure)

I'm starting to doubt my block heater. When a block heater is working does the engine actually feel warm, or is the heating internal or small enough, so you can't feel it by touching the block?

I don't see any testing procedure which would warrant the statement 'glow plugs tested out electrically.' All the evidence points to bad glow plugs, including the non-functioning glow light. What year and model are we talking about here?

__________________
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

1983 CD Turbo.

I pulled off the relay connector and used a multimeter in ze following vays:

1- tested for ohms: neg. multimeter lead on negative battery pole, and the positive testing each socket of the relay connector: all under 1.5 ohms (wouldn't this indicate that all plugs work, since none of them have high resistance?)
2-testing for ohms: neg. lead on engine block, positive lead on the glow plug itself: each one under 1.5 ohms.
3- tested for volts: neg. multimeter lead on neg. pole, positive lead tested each relay post: 12V on each (so, power is being supplied effectively to the relay itself
4-tested for volts: neg pole to both sides of the fuse (just in case): 12v on both sides, even with the ignition turned off.
5-put a wire into each connecting hole on the relay, bundled them together, and ran that to the 12v+, to bypass the relay entirely (just in case). Counted to 25, put connector back on (since the plugs were by now at least warm) and then cranked ignition: engine turned over but wouldn't fire

That's all the electrical testing I could come up with--obviously some of the tests logically overlap, but I couldn't come up with any other directions--they were ways to confirm my other tests (hopefully).

Along with my electrical testing, the key reason I haven't pulled the plugs yet is that I replaced them only a month ago!

I'm still curious about a block heater and just how warm that should make your engine, cuz my engine doesn't feel any warmer than the frame (i.e., really cold).

Thanks for the advice so far--gentlemen and scholars, all!

Procedures seem good. I'd look for less than 1 ohm myself. Oh--if they were just replaced they're probably good. Should see some movement on the temperature gauge from a block heater after an hour or so.

__________________
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

This statement is telling.

I'm assuming that this level of performance has been the standard for some time...........??

I'll also assume that the glow plugs are working fine............as evidenced by your testing procedures and your recent change of plugs.

Therefore, the problem is elsewhere. You have sufficient heat for start.

The only remaining item other than fuel is compression.

I'm assuming you have fuel as the lack of fuel wouldn't be related to a drop in ambient temperature. Unless the fuel gels, the system doesn't care if it is 20 degrees or 80 degrees.

So, that leaves us with compression.

The engine can suffer from lack of compression due to worn rings or leaking valves. The intake valves can and will leak in very cold ambients when they fail to seat. This occurs when the owner operates the vehicle for 50K miles or more without a valve adjustment. The intake valves fail to fully close when it gets very cold.

If the valves are properly adjusted and are not leaking, this leaves you with questionable compression due to rings. Not a lot you can do economically to fix that condition, unfortunately. However, the cranking speed of the starter will greatly influence the compression that is available for a start in the cold. If the battery or the starter are not in very good shape, the cranking speed, and subsequent compression, is reduced...........thereby negatively influencing the start.

You might attempt to bring the battery indoors for a few hours and fully warm it up. Make the start attempt with a warm battery and see if it improves cranking speed.

One final item that greatly affects cranking speed is synthetic oil. If you're running dino in the winter, you're struggling to get sufficient cranking speed in the cold.

Good luck.

Valves, eh? *grimace*

I got the car from my cousin in California in July, and drove it all the way to Missouri. Just this Christmas break, I drove it from Missouri to my parent's house in Seattle, and then back again without incident (well, it was little tough to start some mornings, and occasionally would lose power on the steeper parts of the Rockies...).

Could a car with bad compression make such a journey, or do you think I was just marginally able to?

Any other theories? I just don't want to say curtains on meine liebsten Der Kaiser without being sure it's really dead... *sigh*

Valves can be adjusted--how difficult is this process? And how about compression? I'm figuring the latter requires an engine rebuild.

The terminology of "bad" implies a black and white situation. In reality, we all have shades of grey, unless the engine is brand new.

Engines that have been properly maintained with frequent oil changes, proper valve adjustments, synthetic oil, and working glow plugs generally do not have starting problems down to zero degrees or sometimes less. You'll find that someone will definitely chime in because they cannot resist chirping how they started the diesel at 40 below.................

Those that have a more colorful past, with unknown valve adjustments, unknown oil type, and unknown battery condition will begin to have trouble at colder temperatures.

Whether you have one or more than one of the aforementioned ailments is unknown. But, to attribute your issues to the lack of compression due to rings is a bit premature.

There are no other "theories".

The requirements for a proper start are well known. You must rule them out one at a time.

If you wish to adjust the valves, and I strongly encourage you to do so, here is an excellent pictorial on how to do it:

Mercedes Diesel Valve Adjustment Procedure

I wouldn't do anything without doing a compression test. Typically takes about and hour or so. HF has an inexpensive diesel compression tester.

__________________
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

I would adjust the valves before performing a compression test.

I would also change the oil to synthetic before performing a compression test.

I might even change the battery before performing a compression test.

Why?

Because we frequently find compression figures that are somewhere around 280-300 and it is difficult to make a conclusion based upon those figures.

Furthermore, the test is usually done without any resistance in the remaining cylinders, thereby increasing the available cranking speed, and providing a result that is not comparable to the actual condition when cranking under full compression from all five.

Do the simple things that are absolutely required............first.

Thanks for the advice. I'll be adding Diesel 9/11 tomorrow, in hopes that i can at least get her running again and garage her for further work.

If that doesn't work, I'll try the drain process; then to valves, and so on.

Thanks again, everybody.

If you've got gelled fuel, the addition of Diesel 911 won't help it to start. The 911 cannot get down the lines to the injectors.

If you believe the fuel is gelled, get yourself a pan of charcoal, light it up, wait until the flame goes out and the coals have turned almost white...........and place it beneath the oil pan. Leave it for about 90 minutes or so. If there is gelled fuel in the lines under the hood............the heat from the charcoal will alleviate that condition. Then, the addition of 911 to the tank can have some benefit.

Get it in the garage, do the valves and change the oil to Rotella 5W-40 synthetic (usually available at Wal-Mart).

If the battery is more than five years old............or if you don't know how old it is...........replace it with a new group 49 battery from Autozone. You get an 84 month warranty without the need to save your receipt.

Spend a few dollars on it..........and my bet is that it will reward you with a start in the cold.