hard start when engin cold and glow plug cycles continuously

[technor]

:confused: 83 240D just under 300K runs great and just under 28-29 miles /gal.
Started getting hard to start when engine cold even in 50- 60 deg weather. Cranks well yet sounds dry as in not getting any fuel.
Letting glow plugs cycle several times (10-15 seconds after light goes out) does not seem to make a difference. When cranking get a white-ish smoke out tailpipe.
After 4-5 long cranking times...engine starts and runs fine once it clears fuel loading as in flooding engine.
Once warm, starts normal runs great.

No bubble in secondary fuel filter. Primary filter appears full and no air. Tightened connections, no difference. It seems to me that I might have a leak somewhere in the system but there is no fuel on floor nor wet spots that I can see.

After thinking about it, and poking around, I plugged in the block heater and after an hour or so it started right up.
Also, I have a electrical problem that I think could be connected.
When driving when headlights are needed, glow plug light cycles continuously, but not when headlights are off.

So do I have a glow plug issue, a cycle problem or something else?

Any help / direction to look would be great.

[JIMZ-MBZ]

Ive a 82 300Dt,123

your glow plug relay keeps plugs hot for 30 seconds then clicks Off. You can test it by turning the key to 1st click, and count to approx 30 seconds,,,and,,,you will hear the relay "clunk-OFF" --its located inner-fender drivers front.
(not sure what you mean by 'cycles' ){Im not 100%of all about the relay workings}

I had trouble w/ mine starting when cold,,,changed GP's, EZ (for DIY'R),,,, you can test the GP's and wiring harness w/ohm meter,, follow wires to relay on Drivers-front inner fender probe in the socket holes each should read 0.8 Ohms,, if more than GP-or-wiring faulty,,,,suspect GP first they do get less hot over time.
>>>>just replace GPs

-- advise from here is to wait for approx 10 seconds After the GP Light goes out,
""" the GP relay time "reduces w/ age" and is not accurate, --your GP temp/time is a guess, and NOT an actual reading (( like a water temp ))
>>>>>> I always count to 10 after light goes out,,it starts quick and smooth

--advise from my owners manual says something-to-the-effect-of; "repeated attemps to start the engine will result in increased difficulty-or-Non start of the eng." --> I will be glad to quote it <----
>>>>>> when starting; hold key against stop (engaging starter motor) until engine fires-- even up to 20-30 seconds------>> this is generally acknowledged as sound advise from this forum, for the starter motors are very heavy-duty<------

-- dont pump the 'gas' pedal
>>>>>> you may floor-it and relese it b-4 starting,,,,,, mine starts w/no pedal movement


I had 1 GP out of spec and it caused problems
++++ there Could be other factors at play,, fuel injectors,valve adjustment,etc >BUT< your stated gas mileage seems OK and doesnt point towards these, First.


======= i really am PERPLEXED by your statement about "GP light cycling" GP light should light Once w/ First Click of the key and 'time-out'
>>> PLEASE detail the exact actions of the light,,,maybe someone else has had a similar experience


Jim

[Maxbumpo]

Technor,

Sounds like you have one or more failed glow plugs. Also, when was the last time that the valves were adjusted? They should be adjusted every 15k miles.

A quick test of your glow plugs is to unplug the glow plug harness at the relay, then measure resistance to ground at pins 1 thru 4 (which correspond to glow plugs 1 thru 4). Resistance should be around 0.6 ohms; you need a pretty good digital multi-meter to measure such a low resistance accurately, and you will have to correct for the resistance in the glow plug leads. However, even a simple meter will show an open circuit (infinite resistance) which is the typical failure mode for glow plugs.

When one or more plugs fail, the system will let you know that it needs attention by flashing the glow light in the dash (this is covered in your owner's manual). It may also flash when the relay has an internal fault.

[sbiggers]

What would make the glow light stay on until it starts?

[Maxbumpo]

What would make the glow light stay on until it starts?

According to the owners manual, anytime the light is energized outside the normal glow cycle, the relay is telling you that there is a fault in the system, and the most common fault is failed glow plug(s). You will need to investigate/test to determine the fault.

[technor]

All thanks for the support.
Replaced glow Plugs and started right up. no hesitation. dash glow plug light comes on whith key and 'times out' as you described.

Ive a 82 300Dt,123


======= i really am PERPLEXED by your statement about "GP light cycling" GP light should light Once w/ First Click of the key and 'time-out'
>>> PLEASE detail the exact actions of the light,,,maybe someone else has had a similar experience


Jim


However when I turn on the headlights, the dash GP light comes on as if the key was just turned on and it 'times out'… Remember the engine is running all this time.
And then the light comes on again and 'times out' , then on again, and again and again. That’s what I meant by cycling.

This only happens when the head lights are turned on.

As I work only 10 miles away I do not drive for great distances or time. The last mile or so the temps gauge tops out (water is no way near that hot) so I am getting a false reading.
And when I go through the base entrance you are required to turn your light out as you pass the guard station, all returns to normal. Turn the lights on for the rest of the trip on base and back to pegging the temp gauge.

[Maxbumpo]

Sounds like a ground problem somewhere; a bad ground can force electricity to flow in places and directions it was not meant to go, causing all sorts of gremlins like what you describe. Start looking in the light circuit and look at the battery cables for a poor connection.