2002 M2 240 EFI flooding

[Jdrork]

I have a 2002 speedster with the 240 EFI and it starts cold without an issue (most days) as long as I wait 14 seconds after I turn the key into the on position. All last year it would run fine, but if I shut it off to go swimming, or change out people on a tub it would not start and act like it was flooded. I changed out all of the spark plugs and did find one fowled so I thought maybe it was not firing and causing fuel to collect and flood the motor. If I removed all of the spark plugs and blow air into the cylinders via a pool float pump, and then put in back together it would fire right up. Over the Winter I had it worked on at a marina and they replaced the ECM, and "worked on" the VST. I took it out for the first time and it runs better with all 6 cylinders firing, however it still floods if I am out and riding and then shut it off.

Any suggestions would be appreciated.

 

[ripcuda]

Welcome. Which 240EFI engine do you have? Gen1's have the round flywheel cover, Gen2's have the square cover with an alternator/belt on the top of the engine. There are significant changes between Gen1/2... ECUs, etc.

On my Gen1 240EFI... I experienced the same issue you described. I went through the whole system, new filters, new spark plugs, checked timing, checked VST fuel pressure. Two things really made a difference.
1: sending my injectors off to be pro cleaned/inspected/adjusted (a few were out-of-spec and 1 needed replaced). This made a noticeable difference in how smooth the engine ran and restarting.
2: on the Gen1 240EFI, the ECU is hard-wired to always "choke" (fuel enrichment) when starting. At my altitude (~2300ft) this extra enrichment on a warm engine is not needed and I believe lead to occasional flooding when hot restarting. This hard-wired "auto-choke" is due to a certain red, ECU-trigger wire being spliced (by the factory) into the starter solenoid trigger wire. So anytime the engine is cranking, this red wire is getting 12v and signaling the ECU to "choke". By cutting this red-wire, you can disable the "auto-choke-when-cranking" and even wire it up separately to control choke when you want it. This made a noticeable difference in the ease of restarting for my 240EFI (Gen1).

Cheers!

 

[Jdrork]

I took a look and it is definitely a Gen 1 with the round top.

 

[Tim75]

I took a look and it is definitely a Gen 1 with the round top.

I took a look and it is definitely a Gen 1 with the round top.

I agree with Ripcuda about the injectors. I had mine tested, cleaned, and tested again at a shop in FL. Noticable improvement in fuel burn and starting. About $25 each.

By your description, you have at least one injector leaking. When you shut down, the fuel system pressure is dumped by the leaking injector(s) into the engine.

OR- you may have a failed TPS. Many threads here about it. Hope it's not that. About $750 now. No one has been able to find a substitute.