I noticed yesterday morning there was a lot of white smoke, it usually happen only when it is cold. but this time it was all the time, so I decided to pop the hood, I noticed the fuel was not returning back to the tank. I installed a clean line back when I was burning WMO to monitor the fuel returning, as the car idled nothing was flowing through the line back to the tank.

So I decided to replace the filter, it was back to normal. I still got some white smoke. Where and what happens when the fuel does not complete return back to the tank?

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1984 300D, 1972 LT1 Corvette, 2014 Artic White 3LT/Z51 C7, 2013 650i Convertible BMW, 1994 Kawasaki Vulcan, 1992 Yamaha Seca II and 1996 Dodge Ram 2500.

The interesting point to me is it appears the low fuel pressure to the base of the injection pump can cause white smoke. It had to be enough smoke for you to notice as well.

The sequential timing of the injection pump was involved or changed by lack of fuel to fill the elements equally. Some cylinders late in the cycle may have introduced fuel so late so it could not burn properly. You saw the results perhaps of a partial burn in those cylinders. The white smoke.

This is just another coffin nail in my long held belief now of possibilities for the number one rod failures.

Leaving fuel filters in service till this point is reached is not economy in action. I believe at least somewhat that it contributed to engine damage. Especially more pronounced on the four cylinder 616 though. Again just an opinion or belief of mine.

Not substantiated by proof but highly suspect. I never see anything that makes me question this belief so far. It has been years now that I have held this belief .

I almost wish a poster had not asked me years ago why the number one rod bearings where failing in these engines . I thought that I should find an answer for him as he was right. Failures where consistant and occurring frequent enough to have a look. It was a mental struggle that probably brought on derision in some quarters.

It also took me some time and effort to figure that the understood and long standing belief of the cause was wrong. It just made no sense to me on examination. Yet still was the almost an absolute belief. Lack of adequate lubrication to the number one rod bearing in relation to the others was the belief.

Failure of the number one rod bearing in most cases will occur with prolonged running with low fuel pressure in the base of the injection pump. The causative of this is it makes the number one cylinder work much harder than the others based on the sequential timing of injection pumps elements being progressively fed less fuel.

This makes their injectors late in opening. The elements closest to the lift pump pulse get more fuel than the others waiting for it. The lift pump gives one impulse pressure peak for every injection pump rotation. You had reached the point that some injections where so late the fuel could not be totally burnt.

Or that is my soapbox opinion anyways. The hard part is that I believe this is true but people still do not understand the consequences of running with low fuel pressure. Usually the car will seem okay. This should be checked because even aging of the relief valve spring can contribute over time. Weak lift pumps with age etc. Your number one and two cylinders where probably heavily overloaded with work when the white smoke was present. Depending on the rate of filter plugging they might have had a progressive lesser overload for quite some time as well. Years is not impossible.

Still got some white smoke after warm up? Buy a ten dollar liquid filled 0-30 pound pressure gauge from harbor freight. Read the pressure in the base of the injection pump. If low correct the issues. All causative possibilities are cheap to deal with. Nineteen pounds pressure in the base of the injection pump will make it a different car if you find the current pressure is really low. The white smoke represents lost potential fuel milage and the power boost with good fuel pressure present. You should notice. a signifigant difference. Even Easier engine starts for example as well. smoother idle from a better resulting power balance of the engine is also normal. Quieter engine on the highway is not a bad thing either in my opinion.

I only hope this information proved helpful both as a possible explanation and perhaps a suggestion of how to make your buggy better. If you do the pressure check and improvement if indicated and I think there is an indication that it is needed. Post your outcome. This area has been a hard sell and slow catching on.