Improved starting in 300GD? Please help...
Now I love my '87 300GD, but my wife isn't keen and now isn't prepared to start it. Let me explain, and note this problem has only really started with the colder weather (and we haven't had a really cold spell yet);
Fires up great...
...however then keeps stalling...
...trying to depress accelerator has no effect (well cough splutter and then stall)
...restarts fine but same problem - and each time copious (and I mean street filling) levels of exhaust smoke (this is what embarasses my good wife)
...after a minmum of 30 seconds and usually multiple starts fuel finally seems to get through, accelerator comes to life and able to drive away. Once warm then turn down accelerator advance.
Once going all fine and dandy - exhaust emissions look OK (?)
Now I don't mind the time delay between starting and driving away, old car so mind set is not one to rush... the smoke and stalling however is somewhat embarassing for this 'special' vehicle. Have used injector cleaners etc (supposedly only 65K miles although no supporting documentation but seems realistic to my limited knowledge) and fuel filters replaced last month. Any suggestions?
Hello Stewart & Em,
What colour is the smoking, Black or White? Whilst on starting from cold, you might have a wing nut type black knob on the dash; this is the fast idle, to manually increase idle speed, when the engine is cold. Try using this to see if a difference is made. The idle increase is minute, but sufficient to keep engines ticking over when cold. If the fast idle is automatic then have that checked.
I would look at the glow plug function, that is the relay initially and the plugs themselves. I would have the compression tested and the valve clearances checked and adjusted as necessary. Note: whilst checking out the glowplugs, the chambers might do with reaming; clogged chambers can affect the glow plug performance and affect the plugs service life.
Things start getting more involved from now on, the injectors spray pattern may need looking at then finally the injector pump re-calibrated.
Regards,
Rather than just changing them, and i'm guessing one or more have failed and therefore this is your problem, suggest you test them 1st:
http://www.dieselgiant.com/glowplugrepair.htm
NGK glowplus are £9 ea. from a motor factor. Not Bosch but tbh I've always found NGK to be better quality.
Russ,
Thanks for the link - know what I'm doing next time I get some free time. Now, where did I put the multi-meter...
Has anybody any ever encountered problems removing glow plugs in past? Rakesh also noted reaming - special tools needed or how could I go about this e.g screwdriver in and wiggle without damaging thread?
Cheers,
Stewart
Reply to Thread number Two:
The fast idle is meant to be used during warm up only, to be turned down when warm otherwise the engine will run on as you have experienced when shut down. This must be avoided as there can be engine damage in the long run.
Another suggestion I have, before you reach the stage of servicing the injectors or the pump, there is a cheaper alternative; that is to get a diesel specialist to use a concentrate cleaning agent to run through for a short while, to clean the injectors and valve ports. After that, cleaning adopt the use of injector cleaning additives to a full tank of fuel every six months or so to keep the injectors clean. These can be got from your local fueling station. You can use the concentrated cleaner yourself with some instruction, it is a messy job, that's why I have suggested a garage to do this, should they have the purging equipment otherwise it means adapting to improvise. When and if you reach that stage I can give further instructions, PM me about this at that time.
At a slim chance you may get improved starting, should the glow plugs be an issue, and that is to engage the glow plugs by several attempts to warm up turning the igniton on consecutively in succession until the glow plug extinguishes and then cranking to start up, it may improve starting or not, no harm in trying it.
Cheers,
A few random thoughts:-
Does it have to be turned over quite a bit before starting or fire first turn?
If the steam is white you could have a little water in the fuel tank that is getting sucked through just after starting and while the car is still stationary - this would cause the stuttering.
Have you checked for any air getting into the fuel lines at the filters.
The fuel hoses could have become porus (exacerbated by the PO using bio fuel or something other than diesel).
All simple stuff to check before spending money.
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Hi Rakesh,
Fast idel does make a differencee and I do use, perhaps a small extra tweak on this could help but your advice goes some way to suggesting better maintenance principles. As an aside, if I don't turn the fast idle down, once warm when I turn off ignition the engine will continue to run for a substantial period - could this be linked? Don't remember the name of the unit controlling engine stop but diaphragm was replaced earlier this year in it as engine kept running after ignition removed.
Strangely enough I considered for a long period this year replacing glow plugs and reaming (but finances/time and other considerations - such as last time I changed glow plugs one snapped (the last one typically) in the engine block and the head had to be removed to bore it out - admittedly not G wagen but Freelander) meant I kept putting it off. Even contacted http://www.mercedessource.com/node/4767 (some videos also on his site including checking injectors and compression testing) but never ordered... $90 seems a good deal but alternatives in UK.
Anyway - worth doing plugs?
Thanks