Engine running extremely rich
 

2000 350 Mag MPI

I posted a while back about a hard start problem. Well I found out why, but am having hard time figuring out the cause. The engine is running rich and fouling out the plugs after it runs for a bit. I do not have access to a scanner and the shops that have one are 2-3 weeks backlogged. I'm getting no beep codes though. Computer is MEFI, not sure which number and the boat is not here to get the serial # off of. I just read about a method of using a paperclip and test light to get the codes off the computer on the MEFI so I will try that tomorrow (does anyone have a list of the codes?). Here is what has been done.

New fuel pump because pressure was erratic, pressure is now stable but still same problem. 30 psi, which is correct for this boat.

Pressure reg holds vacuum, and removed the small screen that can get clogged.

Map sensor has proper voltage and voltage drop when vacuum is applied

Changed temp sensor because it was first thought and it was cheap. I did not test voltage however, will do that as well tomorrow.

Changed plugs, cap, rotor, pickup sensor, and coil. Plugs were changed and within 2 runs in the river and a couple testing sessions had to change plugs again due to they were very black.

What all sensors on this setup can cause this type issue? And is there a way to test these sensors with a volt meter and/or test light. Any and all suggestions welcome.

Thought I'd post back and let everyone know what the issue was incase someone else needs the info. The very first thing I did was change the temp sensor because that is the most common cause of flooding in and efi engine. So I used a test light and a paperclip on the diagnostic link and got a code 14. Code 14 is for the coolant temp sensor so I'm like wtf. Well I went to test the voltage to it and noticed that one of the prongs in the plug was broke off. A trip to Orielly and $25 later I have finally found the issue.

Its always good to see people post the final solution to their problems. It may help somebody else out later. Glad it was cheap fix.