Thread: 1997 300tdi Auto Massive Fuel Guzzler

Doubt you would smell it in the oil, it is a diesel! Not that I haven't tried... All silicon hoses mate. I don't think its leaking out of the timing hole. I do get oil out of there but its black. I just checked the engine oil level and its on low after 8 thou since last change. I know, I know, bad me. It's not only the mileage mate, its my wallet. I used to fill up every 8 days at about 700+ after flooring it like fuel was free. I could get better when I drove properly. Now I need to fill up every 5 days for the same cost. Not only does my speedo tell me I'm doing less kms but I drive about half as far as I used to. I used to get another 60-70 kms once the empty light lit up now I'm lucky to get 30. I discovered this recently when I ran out of fuel doing under 60kph on a dead flat rd. I managed to coast 150+m into a servo with five turns, two elevations, three speed bumps and filled up on the correct side!

Sherlock is always right mate! Current thinking is, and feel free to tell me if it's incorrect, to fit a boost gauge on my manifold to ensure I'm getting correct pressures at the intake throughout the entire rev range. If its under I can definitely eliminate the auto, torque converter, brakes, injectors, IP, and the rest of the diesel system. I can then focus on the intake side. That would also mean that its burning the excess fuel, which seems unlikely with the lack of smoke.

Regards,
Lane

You could also check your wastegate actuator[if that hasnt already been mentioned], if the spring has gone soft you wont be getting full boost and will be down on power/smoky/thirsty but with higher egt's

You don't appear to be leaking fuel out therefore you must be burning it, but you say there are no clouds of black smoke. As I understand it, no smoke means air/fuel ratio is correct. Lots of fuel being used with no smoke, so safe to assume lots of air getting in somewhere to maintain correct ratio. Sounds like you need to concentrate on intake. A boost gauge would definitely help here wouldn't surprise me that you are running over boost. Good luck,

I can move the waste-gate actuator with a pair of pliers, just. Seems to have the right tension. Pete, the weird thing is the symptoms don't match each other. It has some pointing in one direction and some pointing in another. I'm leaning towards it leaking and evaporating somewhere I haven't found. Can it evaporate after it is mixed with oil?

Regards,
Lane

I have a Kubota tractor where the injector pump connects to the internal cavity of the engine block. A seal failed at one point on the injector pump, causing fuel to leak into the sump. If fuel leakage into the sump is greater than oil burn through normal running, then you will get a rise in dipstick level. Eventually the sump fluid level will start to cover the bottom of your piston cylinders resulting in rapid loss of power. But if you're leaking oil out the rear you could be outpacing your diesel input (it may be your 't' seals leaking rather than the rear main). As a previous poster said, your fuel lift pump is the most likely possibility, otherwise injectors. With my tractor, the engine oil smelt of diesel and felt thinner.

I doubt diesel will evaporate from engine oil unless your running temperatures equivalent to a fractionation tower 200-300 c GCSE CHEMISTRY - What are the Names of the Fractions of Crude Oil? - Uses - Number of Carbon Atoms - Boiling Points - GCSE SCIENCE. but I could be wrong.

PS earlier you seemed to discount the timing belt out, but even earlier you say not sure when belt was changed - has the belt actually been looked at ie the timing belt housing has been removed?

If we go by the mileage figures on your op from 800 to 600 kms, and assuming you tank is same as mine, about 90l you appear to be losing about 200 kms of travel. Assuming about 11 l/00kms (which is my fuel consumption) you are losing about 15-20 litres between fill ups. That's a lot...If it was leaking or filling up sump I would think it would be visible somewhere? I know posters have mentioned timing belt out, I would think it would be noticeable in rough running or poor starting. Having said that, there are people on here who know a great deal more than I do. I'm sure someone will come up with an answer for you and it will be a "D'oh" moment.

This is sounding like who shot JR Ewing?

If it is getting into the engine then you are either not getting enough air into it resulting in black smoke or the injection timing is stuffed. If diesel is not getting into the cylinders it is either in the sump or on the ground.

Are you always getting your diesel from the same place? Do you need to get weights and measures onto them? Some one is syphoning your tank?

Is 'jumping one tooth' a myth?

I've done a number of timing belt changes on Tdi300 engines and find it difficult to see how a properly set up belt can jump a tooth. The only examples I've come across of belts one tooth out are on forum threads and once when I did it myself, and those instances seem to be where the belts were set up one tooth out by mistake at the outset. One tooth out seems to be the margin of error when setting up the belts.

Has anyone actually experienced a tooth jump? This would imply a vehicle that ran perfectly for many weeks or months, getting good economy and throttle response, and then through some event 'jumped' to poor economy, poor throttle response, black smoke etc. And why just one tooth (the typical margin of error in original set up). Again, the implication would be that the engine was put under significant load to cause the jump - but if that were the case I think we would all be experiencing 'jumps' as we drag raced other 4x4s at the lights.