More Rough Cold Starts...

Mitsubishi Delica L400 production commenced in 1994 -- After much anticipation, the L400 arrived on Canadian Soil in 2009!
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Mr. Flibble
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Vehicle: 1995 L400 Royal Exceed
Location: Issaquah, Washington
Location: Issaquah, Washington

Re: More Rough Cold Starts...

Post by Mr. Flibble »

403delica wrote:Yah i agree! but i would still love to know why it runs rough after the glow plug cycle
My best guesses are:

You don't have enough compression (try a leakdown test?) because compression produces heat in a diesel.
Your timing could be off, injecting fuel at the wrong part of the cycle, causing the engine to not fire at the right time and produce less heat.
Dirty injectors.

Since you say that the smoke is black, here is a listing of black smoke diesel problems that should help you track it down:
Black smoke is the most common smoke emitted from diesel engines. It indicates poor and incomplete combustion of the diesel fuel. There are many causes, including…

Incorrect timing

Dirty or worn injectors

Over-fuelling

Faulty turbocharger (ie not enough air to match the fuel)

Incorrect valve clearance

Incorrect air/fuel ratio

Low cylinder compression (eg sticking piston rings or worn components)

Dirty air cleaner

Restricted induction system (eg system too small or kinked inlet piping)

Other engine tune factors

Poor quality fuel

Excessive carbon build up in combustion and exhaust spaces

Cool operating temperatures


Obviously, worn or damaged components must be replaced, and the earlier you identify and fix the problem, the less damage will be done. Keep on top of engine tune issues, including valve adjustments, and regular servicing of air, fuel and oil filters. Do not buy fuel from suspect outlets. Dirty components, such as injectors can be easily restored to full cleanliness by using an effective and reliable fuel system cleaner.

Black smoke is high in carbon or soot, which is an undesirable product of diesel combustion. Now, the combustion of diesel is a complicated process of breaking down the various hydrocarbon fuel molecules into progressively smaller and smaller molecules, by burning in the presence of oxygen. The main and ideal end products of combustion are CO2 and H2O (carbon dioxide, the greenhouse gas and water). It is believed that the last step in the process is carbon monoxide (the poisonous gas) to carbon dioxide. This is also the slowest step by far, and when combustion conditions deteriorate some upstream bottle necking occurs in the chain of combustion reactions. This results (according to some authorities) in polymerization of smaller partly burnt molecules into much larger ones, which become visible as soot, or black smoke.
Canadian living in Washington USA
psilosin
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Vehicle: L400
Location: BC

Re: More Rough Cold Starts...

Post by psilosin »

My money is on the cold start injection timing advance mechanism not functioning properly.

Not a very common thing to screw up but you have ruled out the usual cold start suspects, and since it runs fine when warm I do not believe the overall timing is out.
403delica
Posts: 270
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Vehicle: LWB L400
Location: Calgary

Re: More Rough Cold Starts...

Post by 403delica »

yah timing an compression are fine... the wax thermostat in the cold start idle circuit might be at fault. it apparently can be rebuilt with the pump... but have not gone down that road yet.
JazzyBC
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Vehicle: Delica

Re: More Rough Cold Starts...

Post by JazzyBC »

Mines been doing the exact same thing. Fine for start up, then a couple of minutes later it conks out. If I keep on it and rev it up, I can usually keep it running, but if it dies on me it takes a bit more for it to catch and start again. After it stops running once, it is usually fine to drive as soon as it warms up. Any fixes sure appreciated!
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