Hey Dave N. you seem to be pretty knowledgable about the MPI systems, ever had 3 codes come up at once ? I find it hard to believe the MAT,CTS and TPS went bad all at once . Its a MPI3 system on a 7.4 Motor is definatly WAY rich.plugs are black and sooty and soot on the transom as well as black smoke fuel psi 42 /no vac and 35ish with it, but once it starts getting warm the gauge is bouncing so fast its a blur !! would a bad fuel psi damper create the codes ? the codes are 14,22, and 23 HELP !!! I wanna shred some water !!!! Bruce

I have not seen those three codes at once, but I believe they share a common ground. An open ground circuit could set those faults and would make it run terrible.

The ground circuits run to the ECM (terminal J2-3), so check the connection there and check/clean the ECM grounds.

Dave

Take a look at the circuit/symptom table below. It doesn't show the ECT sharing the same ground as the TPS and IAT, but looking at the rest of the table (not shown), it does not say where the ECT ground is. I bet it's the same circuit. At least it's a good place to start. Have you tried to clear the codes?

Dave

got it figured out and learned some things in the process ,The TPS was definatly bad.If its bad then you CANT clear the codes until you replace it,so if your trying to diagnose more than one sensor code and the TPS is on the list of codes then do it FIRST,clear the codes then run the motor again and see if there are any new ones that come up.In my case the the TPS had gotten water in it. Anyway , it put the ECM to max rich all the time ,as far as the CTS and MAT codes I think they were symptoms of the motor struggling to stay running but they were cheap so I replaced them both anyway and now it runs GREAT (at least on the hose) your code check method works great Dave thanks