kennyo

I have a procharged 522CI( 1997 502 mag MPI) with a mefi 3. This past year you can start the boat and it fires immediately but then stalls. Then you have to push the throttle about half way and crank before it will start you can't cut the throttle fast or it will stall and have to repeat the part throttle start. I also noticed the plugs load up easier now. I changed out the IAC motor thinking that was the problem. I'm going to try and get the codes read soon. Just wondered if anyone else had this problem before.....Also, how do you clear the codes on a Mefi??

articfriends

iTrader: (1)

Look at it with a mefi program and see if something is screwed up, example, eng coolant temp sensor is bad and tells the mefi its -40 so it adds 35% extra fuel. I used to think it was screwed up that Tyler Crockett didn't graduate the temps and corrections all the way down but in reality you will never boat below 60 degrees motor temp so if mefi adds 8% more fuel at 60 degrees you put that 8% in all the way to bottom in case sensor shorts out or goes open and motor thinks its to cold or too hot. In your case maybe a local mefi tuning guy could drive in boat with you and see where problem is?

kennyo

Would a scan show a bad temp sensor?? It ran fine before on the current tune. What you say makes sense.Thanks for the reply...Beginning to think I've been blacklisted on here....

kennyo

The transom should be really black though, Right??

Tib

I am haveing the same problem with a MEFI-3 and have narrowed it down to the timing not advancing off base timing. I just started a thread asking for other ideas? Sorry I didn't see this thread first.... I'm hopeing it is just the ignition module. Should have a new one today and will post if it fixes the problem.

Tib

Ignition module was the cure for mine. Idols fine and doesn't stall any more.

Trash

The fact that it starts with half throttle leads me to believe you have too much fuel pressure at idle or perhaps leaky injector(s). Half throttle sends the ECM into flood clear mode (shutting off injector pulses). That's my first stab at the problem.

FIXX

iTrader: (2)

+1,,or the fuel pressure regulator's diaphram ruptured and is leaking fuel past it..

kennyo

My regulator is plumbed after the fuel log. So that would cause a loss of fuel pressure i would think. It has gt has the correct pressure with no fluctuation. The plugs all look the same so I don't think leaky injector. The temp sensor does make sense. I need to get it fixed, I have the boat sold.....

kennyo

I did not know that about the throttle!