HwyStar
Registered User
I saw a recent post on someone having a problem with their IRCM, but didnt want to hijack. Tried this in the subscriber forums, and you could hear the crickets.
Anyway, I have a fuel pump intermittently starting on its own with the ignition key off. I put the breakout box on after finding that there was a difference in voltage between verified good grounds to the computer and pin 22 T/LG from the EEC. Pin 22 is used to ground the fp relay to energize fp. Im seeing 1.07v difference. If this was a straight switching ground, wouldnt I see no difference in voltage, or something like 300mV or less as Ford suggests? Im not sure if this is really that big of a problem. I put the BOB on to eliminate the rest of the harness, and Im seeing exactly that difference still. Bad computer??
However, after seeing that, I saw that there was voltage there with the ignition key off constantly. Checked the other side of the relay, and voltage there too. Ok, checked START/RUN pins at the BOB, and had voltage there too. ~~~? This thing does turn off when the key is off, but those two pins still have power. Follow that back and it goes to the IRCM, and Iam getting voltage there with the key off, and no voltage in at pin 13 on IRCM. So, am I correct in assuming the IRCM is fragged with internal relay stuck shut? There isnt a description of operation on the IRCM in the books I have, and Im not sure how that relay is REALLY supposed to operate. The voltage inverter is a little confusing.
Seperatly I saw 0v reference voltage at pin 46 and the car would run like that. I figure I will verify no ref volts AT the sensors too. The other reference volts channel was fine at 5.03v. Starting to wonder...
Anyway, I have a fuel pump intermittently starting on its own with the ignition key off. I put the breakout box on after finding that there was a difference in voltage between verified good grounds to the computer and pin 22 T/LG from the EEC. Pin 22 is used to ground the fp relay to energize fp. Im seeing 1.07v difference. If this was a straight switching ground, wouldnt I see no difference in voltage, or something like 300mV or less as Ford suggests? Im not sure if this is really that big of a problem. I put the BOB on to eliminate the rest of the harness, and Im seeing exactly that difference still. Bad computer??
However, after seeing that, I saw that there was voltage there with the ignition key off constantly. Checked the other side of the relay, and voltage there too. Ok, checked START/RUN pins at the BOB, and had voltage there too. ~~~? This thing does turn off when the key is off, but those two pins still have power. Follow that back and it goes to the IRCM, and Iam getting voltage there with the key off, and no voltage in at pin 13 on IRCM. So, am I correct in assuming the IRCM is fragged with internal relay stuck shut? There isnt a description of operation on the IRCM in the books I have, and Im not sure how that relay is REALLY supposed to operate. The voltage inverter is a little confusing.
Seperatly I saw 0v reference voltage at pin 46 and the car would run like that. I figure I will verify no ref volts AT the sensors too. The other reference volts channel was fine at 5.03v. Starting to wonder...