I have two 700 series with the same issue. One is a 1988 740 sedan the other is an 86 760 wagon. Both automatic. These cars dont get used often. They may sit for months at times without using. They normally start right up, but once I shut them off, they wont turn on. they seem to get flooded(fuel).
The way I get them to turn on is by removing the fuel pump fuse and cranking the engine, after they start I insert the fuse and play a little with the throttle until the idle smooths out.
Both cars do the exact same.
What can be causing this flooding/problem.
Thanks in advance,
Vic

 

Two things were brought up in earlier posts that are good places to start, First check the coolant temperature sensor under the intake manifold #3 cylinder real tricky to get at remove the wire to it and ground it out then try starting it. If it runs normally then replace the CTS it pretty cheap. The other one is possibly an injector leaking into one of the cylinders while the engine is off. I would add fuel pressure regulator as well but some of the threads I read with the same issue say that did not resolve it.

Just my two cents worth.

 

Volvo put out a TSB on this issue. Apparently the cold start injector runs too long resulting in flooding. The solution is to re-wire the cold start injector to run with the starter and only while the starter is engaged.