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1996 - 1997 350 efi ingnition modules 6 variations?

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gofastpilot

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I get it.......... that Mercury needs to improve product but between 1996, 1997 and 1998 there are 6 different ingniton modules with different part numbers for the 350 EFI platform. I have a 1997 350 efi thats throwing 42 and 43 codes from the MEFI-1 ECM. Question is will a module that's not advancing the timing still run? This engine also is hard starting when hot. Engine demands more throttle than sister engine which runs perfectly. I'm still testing yet.
 
As a rule, with an ECU, the timing is controlled by the ECU and not the module.

In that time period, there were lots of configuration changes - and not just on the Mercruisers.

On the EST distributors, operating wo an ECU, the engine will run with an ICM that won't advance the timing....but the engine won't make its normal power output...
 
makomark said:
As a rule, with an ECU, the timing is controlled by the ECU and not the module.

In that time period, there were lots of configuration changes - and not just on the Mercruisers.

On the EST distributors, operating wo an ECU, the engine will run with an ICM that won't advance the timing....but the engine won't make its normal power output...
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Interesting? Info from my Techmate manual says Thunderbolt V 1st gen introduced in 1993 provides spark control from its processor. But in 1996 and again 1998 newer versions with more data collection were introduced. My engine has MEFI-1 and its a 1997 but MEFI-2 came out in 1996. Why wouldn't I have the newer version MEFI-2? Are we confused yet? Thanks for the info by the way
 
boat engine configurations are best managed by serila number...

Its not uncommon for a hull builder to buy a batch of engines and its not uncommon for an 'old' engine to go into a 'newer' hull...in other words, the "year" of a marine engine doesn't mean much.
 
Problem solved with code 42 and 43. Inside what Mercury calls the wiring box mounted to port side of engine elbow I found a disconnected weather proof plug from what is beleived to be knock control module . Don't know how this became unplugged but I cleared the codes and rescanned cleared. So with this disconnected the engine would not advance ignition timing without damaging engine. Don't know yet if this will solve hot start problem. Due to Lake Michigan conditions won't be able to test till tomorrow.
 
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If the mystery module has 5 connector pins, it is the knock sensor...

FWIW, per the manual's descriptions, code 43 is a knock sensor fault and it doesn't appear to be couple to the ignition control fault (code 42). When DTC43 is set, the ECU applies a fixed amount of ignition retard. When code 42 is set, there is no spark advance data from the ECU...the point is you may not be done yet...
 
makomark said:
If the mystery module has 5 connector pins, it is the knock sensor...

FWIW, per the manual's descriptions, code 43 is a knock sensor fault and it doesn't appear to be couple to the ignition control fault (code 42). When DTC43 is set, the ECU applies a fixed amount of ignition retard. When code 42 is set, there is no spark advance data from the ECU...the point is you may not be done yet...
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Stay tuned I'm going out today to see if anything changed.
 
This down on power engine has been bugging me. Compression check revealed it. Cylinders 3 and 5 show 10 psi. all others 180 psi consistantly. Time for head gasket job.............
 
gofastpilot said:
This down on power engine has been bugging me. Compression check revealed it. Cylinders 3 and 5 show 10 psi. all others 180 psi consistantly. Time for head gasket job.............
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Sorry to see the low compression...Did the codes clear up and stay gone from plugging in the knock module?
 
I swapped the modules and for some reason no codes came up. But that doesn't mean anything. The sick engine could still be the cause of the faults.imo
 
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