Td42 Hard To Start When Cold

[Prisc Chandola]

Iresently dropped my 2002 GU 4.2 in a bug hole and got the cold start timer wet. The pre heat light kept going on and off on my way home. Then hard to start for the next 4 days. Got a new timer fitted. (After market). Car was ok for two days but this morning it struggled to start, ran rough and blow white smoke until it warmed up.

Firstly check if the control system actually powers up the glow plugs, then depending on the results measure each plug's resistance or continuity individually. Resistance should be low, around 0.6 Ohms, if open circuit or high resistance means failed plug. You'll need multimeter to do those checks.

Diesel smoke (like blowby and oil use) is a worrying engine symptom which indicates that an engine is not running well, and its service life is likely to be shortened considerably, unless remedial action is taken.

Basically, smoke from a diesel engine indicates that something is not right. It should be taken as an indication that there is a problem existing (or developing), that will potentially shorten the engine life, or result in unnecessary costs. It should be regarded as an opportunity to take measures that will save you money in both the long term and also the short term. At the least, that smoke may be due to a simple problem, that is causing poor combustion efficiency, and costing you in excessive fuel bills (eg carboned up engine from excessive idling, stop start operation or short run times). At the other end of the scale, it may be your last chance to act, before a catastrophic engine failure occurs (eg piston seizure, valve or turbocharger failure).

A diesel engine in good condition should produce no visible smoke from the exhaust, under most operating conditions. A short puff of smoke when an engine is accelerated under load may be acceptable, due to the lag before the turbocharger speed and air flow is able to match the volume of diesel injected into the cylinders. That would only apply to older technology diesel engines, but with modern type diesels, no smoke at all should be evident.

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. If you choose from our range of products, Cleanpower is what you need.

Common rail diesels are the new hi-tech breed of diesel to meet ever increasing emission standards. Operating pressures and temperatures are several times higher than older technology, and tolerances are much finer, making them more susceptible to fuel and deposit issues. Injectors and pumps are naturally more expensive, but problems can, and do, melt pistons and destroy engines. CRD Fuel Enhancer is fast becoming the standard for correcting and prevention in Australia.

Cleaning of internals of engines has usually only been possible at overhaul, however, Cost Effective Maintenance provide two products to enable vehicle and equipment owners to quickly, safely and cheaply restore full cleanliness to combustion and exhaust spaces (FTC Decarbonizer) as well as piston rings, oil pumps, oil galleries, oil coolers, piston skirts, valve gear, etc (Flushing Oil Concentrate).

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.

At cold start, blue smoke is often evident, and can reflect reduced oil control, due to fouling deposits around piston rings or cylinder glaze (which is actually carbon deposited in the machined cylinder crosshatching. These tiny grooves actually hold a film of oil, which in turn completes the seal between the combustion chamber and the oil wetted crankcase). Blue smoke should not be evident at any time, but it is worth noting, that engines with good sound compression can actually burn quite a lot of oil without evidence of blue smoke. Good compression allows oil to burn cleanly, as part of the fuel. It is not good though!

Once again, restore physical cleanliness to all components. Replace worn parts where necessary. In some situations, where the engines are pretty worn, but you just need to keep them in service, cleaning with the previously mentioned products, followed by effective additional anti-wear protection, will reduce internal stresses on all those tired components, providing extended service life. Our AW10 Antiwear achieves this for many of our customers.

When white smoke occurs at cold start, and then disappears as the engine warms up, the most common causes are fouling deposits around piston rings and/or cylinder glazing. Use of our Flushing Oil Concentrate and FTC Decarbonizer address these respective problems.

Water entering combustion spaces will also create white smoke. Faulty head gaskets and cracked cylinder heads or blocks are a common cause of water entry, and are often to blame. Unfortunately, expensive mechanical repair is the only proper solution here.

BLOWBY (or BLOWBY SMOKE) is the emission of crankcase pressure (and fumes/smoke) out the crankcase ventilation system, and generally regarded as a clear indication of an urgently needed, and expensive, engine rebuild.

It is evident as pressure coming out the crankcase ventilation tube, valve cover breather or dipstick tube. Engine oil leaks can also result from excessive cylinder blowby, as the excess pressure finds the weakest point. Some causes include

In practice, only about 20% or less of diesel engines have suffering excessive blowby caused by worn or damaged parts.

Over 80% are attributable to piston ring deposits that cause the rings to bind in their grooves. Cost Effective Maintenance has demonstrated that excessive blowby in these units can be minimized at low cost and without downtime.

A hard starting engine is the most common indicator of damaged glow plugs. In cold conditions, without correctly functioning glow plugs, the combustion chamber may not reach the right temperature to ignite the fuel and start the engine. If there are no problems with the fuel or the battery, then glow plugs should be checked.

The combustion process in diesel engines requires a high rate of compression, fuel injected at the correct time and in the correct amount. This ignites the diesel fuel, resulting in combustion. Misfires can be caused by issues with fuel quality, compression and fuel injection.

The combustion chamber heat comes from compression pressure and glow plug heat. It needs to reach at least 450 F / 232 C for ignition to take place. If the glow plugs are faulty, the engine chamber will not reach the required temperatures.

If one or more glow plugs have burned out, are carbon fouled or damaged, the engine will become progressively harder to start as temperatures drop and will idle roughly and produce white smoke from the exhaust for several minutes once it finally starts. If all the glow plugs are burned at their tips, check the fuel injection timing.

Based on local climate, diesel may be blended with specific additives during the cold months to lower its freezing point. The blended fuel will most likely have a lower energy content and provide reduced fuel efficiency. Engine operating temperatures should be adjusted to ensure all the injected fuel is completely burnt. Glow plugs help to provide the additional heat in the combustion chamber.

Damaged glow plugs or a faulty glow plug control module can cause white smoke on engine start up. There are also many other possible causes for an excess of white smoke, including low engine cranking speed, low compression and air in the fuel system. If white smoke is still visible after the engine has warmed up, the engine may have one or more bad injectors, retarded injection timing or a worn injection pump.

DENSO Aftermarket has an all-makes, OEM quality glow plug programme. From superlative start-up performance to extended post-heating temperatures, DENSO Glow Plugs offer complete choice. The programme encompasses all current glow plug technologies including single coil, double coil, extended post-heating, ceramic and instant heating.

Suits: Nissan Patrol GQ Y60 & GU Y61 with TD42 engines.

This listing is for a Set of 6 Glow Plugs.

Common Diagnosis of a Faulty glow plug can be hard starting when cold, or White smoke on startup, when cold.

We only stock Japense Brand of glow plugs.

Sometimes Bosch, HKT, or Dreik will be supplied, it will depend on what is available at the time. All 3 brands that we stock are quality Japanese brands.

If you are after a particular brand, please contact us before purchasing to check to see what is available at the time.

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