Thread: Question for the diesel mechanics

2l engines are pretty bullet proof. Blocked fuel filter will make it run slow under load but have minimal effect no load,blocked air filter will make it hard to start (same effect as a flat battery or weak starter motor)smooth idle but rough at 1500rpm suggests to me it isnt running on 4 ,the lumpy running and smoke suggests unburnt fuel from cylinders not firing. This can be due any number of reasons but mainly a lack of compression .I would leave it running a while to see if it clears its self but if youve done the normal things like changing filters,draining the old fuel(diesel bug) and its still faulty you will need to dig a bit further. Firstly bleed the injectors and check fuel delivery to each. The injectors on 2l are a pintle nozzle and pretty rugged but can fail if blocked with crud. The injector pump can be erratic if left unused and the o rings and seals fail especially on older units that were run on high sulphur fuels from the 80,s and 90,s.You can normally see fuel seepage from the pump top housing and side fittings. This normally doesnt cause erratic running but I have had an occasion when it did. A kit of orings seals and gaskets fixed the fault. Remove the radiator cap and run give a few revs,check for bubbles in the water(this can mean a head gasket failure between cylinders and water jacket,but not always) Under no circumstances add water to a hot engine even when running as this will crack a 2l head instantly(the thermostat housing dumps directly to the cylinder head) If after all this the fault is still there then you will need to do a compression test. At this stage you can expect things to get expensive.