Here are the symptoms on my 1993 240 with B230F engine:

No problem with cold start when ambient temp below 50F.....all is well.

Yes problem of slow start (about 5 revs), then rich rough idle for 5 seconds until self clears at ambient temp above 50F. Most always behaves this way on hot re-start. Immediate hot re-start usually not a problem, if the re-start is within 15 seconds. Waiting longer than 15 seconds and the problem hot starting occurs 95% of time.

Problem of slightly uneven slow idle at all temps...the engine doesn't run sewing machine smooth at slow idle(nor do I expect flawless idle either, considering the form of fuel injection), but it has these annoying micro-hesitations at irregular intervals..kind of like an electical miss, but not that severe...does that description sound familiar?


Would you agree/disagree with the following assessment - one or more of the fuel injectors is spraying fuel in stream instead of cone? On shutdown, the same injector(s) is/are leaking fuel down into cylinder causing the balky startup when temps are above 50F. Below 50F the startup isn't a problem due to the need for extra fuel in cylinder(s) anyway. Engine cold and below 50F and it starts immediately on turning the starter key.

The engine has 155K miles on original injectors. I have replaced about everything pertinent on the engine that can be replaced to eradicate this annoying behavior....plugs, dist cap, wires, fuel pressure regulator....but the same symptoms persist. The fuel injectors are the last suspects I have.

Any other suggestions are most welcome!