Originally Posted by flowershin5

I'll follow up here in hopes this may help someone:

This is much later, but I'm posting as it may help someone. I have a 99e300 188,xxx. Intermittant no start, with no DIL trouble codes. I added a rear electric fuel pump and replaced all o-rings with viton, as well as by passed the pre filter and added inline filter further towards tank. I did this because it looked like I was getting air in the lines when It wouldn't start. None of this fixed the issue. I had all good glow-plugs, and controller connection and harness seemed good. SOV tested good, and wires to it tested good. But when I had the no start issue I could see that the sov wasn't being activated by the PCM (causing what looked like air, but more than likely just fumes pulled out of the fuel by vapor pressure, and vacuum). Also when I had no start it would crank, and start just a little bit, but even when I let of the key, it would continue to crank until ecm timeout. When this happened I noticed, I got not rpm on the gauge. Now you may see where this is heading. I read on a forum that the crankshaft position sensor could cause a crank no start. So on my live data using a scan tool, and with a multimeter measuring the ckp ecm pins (during cranking you should seem some ac voltage maybe less than a volt). When the car wouldn't start I wouldn't see rpm on my scan tool and I got 0vac on the multimeter (when it would start you would see about 2 volts on the old ckp, and on the new one over 3 at idle usually). I suppose that if the ECM doesn't see crank signal then it disables the sov? It would be better to use a scope on this to see any weird signals, but I didn't have one, and a multi meter proved to be enough to diagnose this. Anyhow I replaced the ckp sensor with a matching bosch part number, and the car now starts normally every time for over a week now. I was using Mitchell's erepair database....it has very little info on how the ecm controls cranking, so it was next to useles, but this is the best I can figure, is the the ecm is looking for ckp signal during cranking and without it, it may disable the sov.

greazzer in regards to your post, I think I will look into making biodiesel, and running a light mix of filtered wvo instead of the wmo I have been running. I and leave the wmo to my 5.9 Cummins. Thanks for the advice, I want to run alternative fuels, but run them safetly.