My 72 1800E recently developed a problem with hard starting when warm. The car starts instantly when cold but will not start once warmed up and then killed. It also has been running progressivly lean. I will richen the mix at the map sensor and it will be good for a week but then it will start to go lean again. I have tested the following.
1) Fuel presure at all r.p.m.'s 28 p.s.i. (good)
2) Resistance at engine temp. sensor (good)
3) Resistance at air temp. sensor (good)
4) Can not find any vacume leaks
5) Resistance at map sensor (good)
6) Triger contacts (good)
7) All 4 injectors are firing properly

Have not tested the cold start injector yet but will.

You can be sure the cold start injector is not the problem. It sounds to me like you do have a vacuum leak, and that it's getting progressively worse. One possible source that's easy to overlook is the vapor cannister behind the grill. A disconnected or cracked hose there will make the car very hard to start warm... of course, it could be anywhere, but check that system too.

The car is fuel injected. Would the same still be true. On fuel injected cars the leaks would happen upstream of the fuel rather than after the fuel has been mixeed so I would think that it would only make it idle faster. Unless it were a later model volvo injection system that has an air mass meter. No 1800's have mass meters though they would have m.a.p. sensors that would compensate for the leak. Let me know if I'm overlooking somthing here. Hey,I could be wrong.

Thad

Yes, it would still apply. I fixed this exact problem on a friend's '72 ES, which of course has D-jet injection. I also had the exact same thing on a non-Volvo with L-jet (airflow meter, instead of manifold pressure or air mass).

Air leaks can fool D-jet into running rich, lean, or just not tracking right.

Time to look for vacuum leaks.
Thanks for the info.
Thad

Do you know of any problems with not having a charcoal cannister? The PO of my '70E removed it. I have not checked if the lines are plugged or not, but I have a cold start problem, but OK warm.

Tom

The cannister, or lack of one, should have no affect on starting or running. If it's not there, the lines should be plugged... but if they're not, I doubt that would cause a cold start problem.