I have had 17 VW diesels. I have had engines all apart have been in Injection pumps have and injectors, i adjust my own valves etc. I am not saying this to look like a hero just to equate you with my mechanical aptitude. This problem stumps me. I have 2 vw diesels both NA. One is an 85 mechanical lifter and the other is a 91. I have had the 91 about 4 years and after owning it for about 18 months I noticed that I started getting a significant soot buildup on the trunk. The car burned ZERO oil. I had put a rabbit style fuel filter on it but have done that on many of my diesels with no issues. I loved the big bumper body so I decided to trensplant the great running m85 mech motor into my 91 body. The 85 motor didn't burn oil, had great acceleration and no soot. So i made the transplant and now the 85 motor produces soot and the 91 motor in the 85 body does not. The 91 body has always needed about 2 seconds of cranking to start unless it is the first start with glowplugs. I was frustrated as heck at Christmas so I ripped off the water separator under the car and plumbed the lines together. I am lost as heck. Swapping motors in 90 degree weather was not a bunch of fun and i still have the problem. Thanx for any help.
Fuel line weirdness? Tank venting weirdness? 1cwt of soot still sitting in the exhaust, collapsing air intake pipework, something that is still with the car? Happy Puzzling.
It's obviousy fuel feed related, why not get a lift pump and see if it helps. Advance and Autozone has them for 45-60 dollars, the $60
one by Mr. Gasket is Diesel rated and has a pressure rating of 4-7 lbs. They help eliminate those damn air bubbles too.
I talked to a local truck diesel guy and he said check the return hose for blockage and I checked it against an 85 diesel I have and the 2 are pretty close. Any suggestions on how to check the fuel lines? I have looked and there is no visible leakage.