GT40 Hot Start Problem

I have a 99 Super Sport with hot start issues, but once it sits for 15-20 minutes it fires right back up and runs fine. The problem is worse when the weather is hotter and or the engine is working harder.
I have replaced the following.
The relay for the fuel pumps and ECM.
Low pressure fuel pump (you cannot hear this cycle on during the 15-20 minutes)
Also have done the following.
Sent the ECM out to have it checked by DIM, they said it was fine.
Bypassed the safety kill switch.
The boat and engine has 320 hours
I have read most of the posts on this issue but still cannot figure it out.
Help.

I have not checked the FCC. I will be bringing the boat home from the lake tonight and I will check this. Thanks

Hi and welcome to the forum. Do you have a digital volt ohm meter? Heat soak the engine. Turn it off, Unplug the low pressure pump. Turn on the key, should have battery voltage for 3 seconds. Then unplug high pressure pump, Repeat test. If you get battery voltage on both test then you have a pump problem. On the back of the engine there is a EEC-IV test plug. You can look on the forum how to jump out two wires to make the pump run for testing. With a Gt40 engine you should have about 39 psi on fuel rail at injectors. Hope this helps.

This is how to jump the fuel pumps so they run continuously


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Colin yes jumper the EEC (STO) to run pumps is the first step in diagnosing this problem.
Check out this Thread it has lots of info in it that is relevant to your problem.

Hope that you do not have a faulty ECU. But these GT40 ECU's have now had a lot of extreme heat cycles in the approx. 20 years they have been under that engine cover. They are no longer available but there is a thread on PN about using another compatible Ford EEC1V computer and updating the code to the PCM program.