91 350SDL - are there Monarch nozzles available?

I have converted an 83 300TD and am quite happy with this car. I put Monarch nozzles in the injectors.

I have a 91 350SDL (118K) that I want to convert with a two tank system. I have it installed and checked out getting oil from the tank in the trunk where I have the WVO pump. No problems getting oil all the way through the system. The air has been pumped out.

I checked the WVO tank and made sure air could enter it as I pump WVO out of it.

I switch over when the oil is about 140 degrees and the engine soon starts chugging and then dies. If I switch back to diesel and crank for a bit, then I can restart the car.

Even if I switch over when the engine is warm and the car is just idling it is not very happy. (unlike my 300TD).

Could it be the stock Bosch nozzles? I don't see on the web site that you have any Monarch nozzles that is compatible with a 603.970 engine.

The oil does go from the valve to the diesel heater (on these engines) and then lift pump, straight to IP. It does not go through the diesel filter.

Any advice on next steps I can try would be helpful.

thanks, steve