I thought I would begin this thread by describing the somewhat amusing circumstances which led to this car sitting dead in my driveway, but after reading back through it, it doesn't seem quite so amusing anymore, so maybe I'll just stick to what I think is useful information and see what you all think.

This is an '81 240D with 94K (49K on the current odometer, and an official sticker from the state of South Carolina saying when the first one broke.) However the current odometer broke 9 miles after I drove it away from SC, giving my cynical self reason to doubt the veracity of any odometer reading.

Only two owners, the first a surgeon who verified the mileage when the first odometer broke, and was replaced, the second, his mechanic, who I bought the car from.

I never had the compression checked before I bought it.

I live in Maine. I drove the car home from SC in April of 2007. On the 1500 mile trip home, it burned approx. a quart and a half of oil. It started well and ran well all summer long, whenever I used it, which was about once every week and a half. (I live on an island and drive a ferry during the summer, don't get to shore much during the busy season.)

The first time I tried to start the car after the weather got cold (40 deg?) it would not start. It eventually did after connecting to another car with jumpers. It was at this time that I accidentally discovered the air blowing out of the oil fill cap while the engine was running.

The car started well and ran well for a while again(don't remember temps.) Then when it got cold for real, it has not started since. Before even picking up the car in SC I ordered a block heater knowing I would need one here in Maine. Thinking that if the compression is suspect (the oil fill cap blowby?) a little warmth might make all the difference, I installed the block heater, (and ordered a compression gauge.) The block heater works really well, on the day I tried it, the block was warm, if not actually hot to the touch, certainly as warm as a summer day starting from cold. Nothing. Did not even think about starting. So next I checked the compression with the General tools gauge that I have read a lot of you guys talking about. I measured two cylinders through the glow plug holes before running out of light (working outside on a car in the winter in Maine sucks) but the two values were so depressing that I quit. Cylinder 1- 170psi Cylinder 4- 290psi. Both glow plugs worked though.

Next I decided to gap the valves and see if that changed anything. It was obvious as soon as I had the valve cover off that if the injectors were gone, gapping the valves would be much easier, so I took out all the injectors. They didn't look horrible to me, but there was a little carbon around the orifices on all of them. Some better, some worse. After the valve job, I checked the compression on all cylinders through the injector holes. Of course the values are on a cold engine since this one is pretty much perpetually cold these days. Cylinders 1,2, and 4 were 230 psi. Cylinder 3 was 210psi. Boogars.

Since I had the injectors out, I had them bench tested. They all popped off at around 1500 psi, and dribbled and squirted instead of misted. The guy who tested them took a new one off the shelf and showed me what it was supposed to look like, a fine mist that just hangs in the air. He said that all four of mine were bad enough to make the car hard or impossible to start, and run poorly.

Well that is good news I said. That might pretty much be the answer. Except when I told him about the compression values. His response was, "Oh, thats disappointing." Master of understatement this guy.

So the compression sucks, and the injectors are bad. So my questions are these:
1. How accurate is the General tools compression gauge?
2. With compression values this low, should the car have ever started or run well?
3. If I mimicked a hot summer day with the block heater, why didn't the car start, if it started all summer?
4. Are compression values comparable if done through different orifices? I can understand why cyl. 1 might have gone up after a valve job, but why did cyl. 4 go down, unless I made a mistake somehow.
5. Is it time to be contemplating giving up on this engine, vs. sinking more money and time into new injectors etc., etc... The shred of hope I am clinging to (in the face of those compression readings) is that the car ran and started well. If it doesn't now, then something must have changed. And if something changed, it can be unchanged. Compression values and injector function don't change overnight do they? I thought that problems there accumulated over long periods.

Thank you guys for reading as I babbled on about this one. Any ideas?