Our 91' 240 sedan has 140k. Well maintained. No rust or corrosion. Will refuse to start or will die at moderate speeds when outside temp 90+ and engine not warmed up. After refusing to start this afternoon I took a garden hose and cooled off the engine, paying particular attention to the intake manifold. The engine started right up and ran until it started warming up a bit. It then died and again we tried to start it without success until we got the garden hose out and cooled it off. Started right up. This time we kept it revved up and after the engine warmed up it ran OK.

Any suggestions as to the likely cause? Thanks in advance.

It might be the ignition coil. I had an ignition coil that would put out a weak spark after the car warmed up on hot days just like yours. It would die and then not restart until the temp had decreased significantly.

It could be what some of the other guys suggested as well. But this is one more thing to check.

I know of someone else fighting the same problem in a 91-- up around NYC. If I had his car to work on the first thing I think I'd do is check residual fuel pressure guessing there's a volume of vapor in the rail possibly due to a leaky check valve at the pump.

Today I tested another LH2.4 car for that, but it held 42# for well over a half hour, and three hours later was only down to 25#.

Any codes from ECU or ICU? How does it start after being run hard, like at the filling station?
--
Art Benstein near Baltimore

I thought pouring water on a hot engine is bad because the drastic temperature change can cause the metal to crack. was yer engine at operating temp. level when you hosed it?

At ambient temp. water should not hurt, of course. But... When I was first driving, the clunker I had started overheating fairly often. Once, I hosed the engine down to cool it off. Later when I took it to get the cracked head checked on, the mechanic looked amazed. He had never seen a head cracked across every cylinder like spider webs.

The engine was warmed up to the degree imposed by the August South Carolina sunshine.

The only thing I can think of is maybe the power stage, which has a heat sink and is coated at the contact surface with thermo conducting grease, is failing. Just a thought, a possibility picked up from miscellaneous Brickboard posts? The power stage is a small module bolted to the inner fender by the battery, as I recall. Large wire harness connector for a small part the size of a thin deck of cards. Kind of trapezoid shaped, gray plastic and metal