Logo

Need help! 40hp EFI will not idle down below 2500rpm

RallyPoint 2020

New member
Hello everyone!

I am stumped and need help from those of you more knowledgeable than me. I have a 1999 40hp Evinrude EFI 4 stroke (E40PL4EE) that has been running great all year until just recently. The other day I went to start the motor and it wasn't receiving fuel past the high pressure pump. I removed the VST and found the fuel pump connector inside shorted out/melted which left the pump powerless. I ordered an aftermarket fuel pump UC-T30 with harness and installed it, then reassembled everything. The motor started on the second attempt and instantly ran at 3000rpm in neutral. Sometimes it will drop to 2500rpm after running 30 seconds, but it holds steady between one of the two rpms. It runs great on the lake 3000-6000rpm range, but it will never drop below 2500rpm when in gear or neutral.

My initial thoughts:
1. Air leak somewhere following reinstallation? I cannot find cracks in hoses or intake manifold gasket.
2. Could the new fuel pump be applying too much/not enough pressure to injectors?
3. Fuel pressure regulator suddenly become faulty?
4. Verified throttle body plate is closed, but still idles at 2500-3000rpm

The motor idles as if the throttle is cracked open partially. I did not make any adjustments when I replaced the fuel pump. The motor ran flawless prior, started up immediately every time on first try. It will no longer start on the first try, it now requires a second or third attempt at turning the key to get started.

Am I missing something?? Please help!
 
Last edited:
FIXED!! Through lots of researching, I decided to focus some attention on the IAC. Upon inspection, I found one of the hoses detached when I initially removed the intake manifold. When I had reassembled the motor, I was not aware of that hose and it was in a unnoticeable location. It created a substantial vacuum leak which resulted in my high idle issues. Reattached the hose and the motor runs at 1000rpm using muffs. I anticipate the rpm to drop a little more once under load in water. If any of you have a similar issue with high idle, make sure to double check the IAC!!
 
Back
Top