Ive got an 87 300D which is loosing its prime after I shut down. This is resulting in very long cranking (30 sec) to light off. I am running a Frybrid VO system, which means the diesel plumbing has been re-ordered such that the lift pump outputs directly to the IP. This means the whole diesel system (main filter + fuel preheater) is all under vacuum up to LP. Also, since there are now 2 non-mixable fuels, I had to plug the banjo bolt in the diesel return line at the main filter to prevent wvo from washing into the main filter.

I have tested for air leaks by disconnecting the inlet line to lift pump and plugging it. Then I disconnected the diesel source line from the hard line which comes in from tank. I pulled 15 in HG on the diesel lines between Lift Pump and diesel inlet and it held overnight. So I have no vac leaks in all the diesel line from inlet to lift pump.

I noticed the little 1/8 lines that run from injector to injector say SAE30R7 – NOT FOR FUEL on them, and the 1 on the #3 cylinder it is leaking a bit. Would this cause me to loose diesel prime after shut down? Any suggestions as to why its loosing prime are much appreciated!

Once the engine lights off it runs perfectly, it’s just starting it that is a real pain.

I told you guys I would report any problems Ive had using this wvo system, and this is really the 1st thing that’s come up in 25,000 miles. I had to replace the starter due to long cranking, and also needed to replace all 6 glow plugs in this 25,000 mile time frame, but that may have been due to long cranking, or not purging the wvo out before shut down when the engine would be restarted within 30 minutes on a hot day (I always purged when shutting down longer than 30 min). The motor still runs very well and is well maintained, and I routinely see 100 mpg dino so this idea merit. I just need it working perfectly before I get back in it.

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Paul
Benz-less
I need an SDL !