How to determine if a MEFI 3 Ecm has failed 

Ted once again a great video. Thanks

Excellent demonstration

Hi Ted, great video, thanks! I have a 5.7 Marine Power Vortec with a Mefi 3 or 4. The boat had been swamped. I’m not getting key on power to the fuel pump. I have pushed power to the fuel pump and the boat starts right up. Would it make sense for the Mefi to malfunction with only the fuel pump but everything else works fine? All fuses and relays are new. Do you know a place I can send the ECM to get tested or a place to buy a new one? They seem hard to find.

Hi Ted. I ran across your video and have very similar circumstances. I have the same marine Dephi ECM (16237009) which certainly appears to be faulty as the relay driver (J1-23) is not grounding the fuel pump relay, and there is NO communication to diagnostic equipment. 12VDC Fixed and Wake-up are available to the ECM, and the ECM grounds are good. I used the Rinda CodeMate blinker and did not get the code 12 diagnostic capability acknowledgement. I then bit the bullet and invested in the RInda Diacom software which does not connect to the ECM ("The ECM is not repsonding or the cable is not plugged in..."). I then sent the ECM to a repair shop who says that they found a Checksum error and resolved it by flushing and reloading the software (I'm not sure how this could have been possible if the ECM is not communicating, but perhaps they have more sophisticated equipment). The ECM still shows same result--will not communicate to flasher or Diacom. I now fear a new ECM may be in my future. The Delphi 16237009 seems to be obsolete. Any insight you can provide on repairs or replacement is greatly appreciated. My engine is 1999 Volvo Penta 5.0GiPWTR

Thanks Ted. I have a 5.7 Gi-E. Where can I get that manual that has the pinouts that you showed?

Hey Ted, I have the Delphi 16237009 on my Twin 2000 Cruaders 5.7 MPFI engines. This runs on the MEFI 3 based on my Ri nda TechMate Pro. My engine hours for my Port engine are reading crazzy numbers. It reads like 75453.32. I read the correct hours before which is suposed to be 725 based on my engine hours meter at the helm. My starboard engine reads the correct hours when using my techmate pro. Any reason why this could of happened all of a sudden? Would greatly appreciate any advice! Thanks

Hey Ted, been watching your videos, I have a 2001 mercruiser 5.0 with a MEFI-3 16236999 ECM. I have tested the ignition and fuel pump relays as indicated in your videos. I have the no alarm and no fuel pump sounds when I turn the key on. I can crank the engine. I do not have access to Diacom diag software, too expensive for home use. Is there some way to test the ECM without the diag software. I also hear that they have discontinued this model of ECM. Do you know if there is an upgrade available. Been searching, cannot find anything. Thanks for any help you can give.

Hi Ted, I have a question about MEFI 1 (97 8.2 MPI) any ideas on what would cause multiple diagnostic codes (I.e. MAP/IAC/TP faults) using Techmate Pro when engine starts, rough/high idle, extremely rich exhaust and error codes are different each time engine is shut down and power is reapplied. Months before this I noticed a reduction in power when full throttle was applied as well as reduced WOT RPM.

Hey Ted. Great video!! I have one engine right now that I believe the ECM is starting to fail. Fuel pump failed, replaced fuel pump and had injectors cleaned. Engine still idled terribly. Plugged in scan tool and saw I could communicate with the engine but when doing power balance test with DIACOM it was very inconsistent. Some would react others wouldn't. And it always was changing. 1 point I had all cylinders not reacting and engine was running perfectly. Any suggestions? Also I had codes with almost all 5v references saying high voltage.

Great Video. I was installing a new knock sensor and tapped the wrench on the started now nothing when I turn the key. Engine will crank but fuel pump won’t prime. I jumped the started and it turns on. What’s the best way to test to see if I fried my Emc without a scam tool? Any ideas on what happened? Checked all fuses and the look good. I’m stumped

Hi Ted, Do you have access to calibrations for MEFI 3 and 4?

Really odd that both ECM's had No Com with scan tool but you could see live data (unless I missed something in my not so undivided attention). That scenario usually points to the CAN Bus down but both ECM's? Lightning strike is definitely plausible. Looks like we'll be bringing lab scopes into the recreational marine shop sooner than later. Awesome to see ECM troubleshooting vid on RU-vid. I test them as well. Dealerships are so quick to throw new ECM's at engines.

Hi Ted hope you are fine,I am looking for 2 ecm of VOLVO PENTA 5,7 GXI-FF ,do you have idea on the rebuild or replacement solution . Thanks

Thank you for all these informations; My Mefi 3 is also burned. Do you have a solution to replace it by an other system because Mefi 3 are not easy to find as you know?

Interesting, thank you 👍😁

I need 2 MEFI 3 ECM's, mine were hit by lightning. anyone know where there might be 2 for sale?

Hey ted I have a 2003 4.3gxi, it was running fine for about two hours it had about two blips running at idle the beeper went kinda stalled out but ran fine after i parked it at the beach, went to start it a hour later and it didn't have any beeps, no fuel pump got it to run again started randomly then it started to beep and cutout again then finally shut off. I got it towed back it beeps randomly and fuel pump turns on. It keep beeping whenever it wants too, it wont stay on looking tried looking for lose wiries any tips?

The lost art of diag. Too many techs today guess and throw parts at a problem.