350 Mag Code 43

Etzler

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Jun 8, 2013
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350 Mag Towsports. Starts, idles, but has no power. Running very rich. Throwing a code 43. Full disclosure. Boat was sunk and recovered. Cleaned all connections and replaced several items. Coil, crank sensor, plugs, wires, cap-rotor and fuel pumps. Fuel pressure is roughly 35 psi.
 

Fun Times

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Hi, what is the engine year and serial number?

Since you mentioned Crank sensor, it's probably 2003 or newer? Do you have a service manual to work off of?

^ If I'm correct, 'Working off of that info thus far, code 43 should be EST 1 - 8 - Electronic Spark Trigger (or "Timing") signal to the ignition coil driver circuit is open...In your case # 1 is open.
Fault Explanation:
Ignition fault. Signal from ECM to ignition driver module open. Detectable only with the key on and engine off.
Root causes: Wiring problem, Sensor problem or ECM problem.(< Which is most likely the case as coil driver failures are sort of common on some ECM's.)

You mentioned new coil, The coil assembly probably also came with a new coil driver module too all connected together as one such as Mercruiser part number 8M0054588 correct ?, http://www.ebay.com/sch/i.html?_fro...C0.H0.X8M0054588.TRS0&_nkw=8M0054588&_sacat=0

If the fuses are good, and all the ground wires/cables are clean and tight all over the engine, then for something's to check if desired, you may have a broken/lost wire connection between the ECM and coil driver module. The ECM Pin-Out # looks to be Pin B-23 which should be a White with Dark Green wire. http://boatinfo.no/lib/mercruiser/manuals/mercruiser36.html#/102
http://boatinfo.no/lib/mercruiser/manuals/mercruiser36.html#/66
http://boatinfo.no/lib/mercruiser/manuals/mercruiser36.html#/10

You or a service tech would typically need to volt test and ohms test all the wires going to/from the sensors, ECM and fuses for 12 volt, 5 volt, and ensuring the continuity circuits are not lost on each side of all the components in question.

If all that seems to test out good, then again most likely the ECM is bad and needs repair...And to be honest, since the boat was under water, and if you haven't done anything with the ECM, then the internals are most like water damaged/flooded and needs inspection and possible repair. Water damage to the ECM from being under water is common with the newer ECM's and so are driver component failures. There are only a small few that know how to test/repair these marine ECM's... The cost is $600.00 for actual repair..., https://whipplesuperchargers.com/index.php?dispatch=products.view&product_id=73

Hope this info helps you out somehow, Keep us updated on your progress, good luck.
 

Fun Times

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^ Just wanted to mention as a starting point to all this that If I'm incorrect about the engine year and you have a MEFI 1, 2, 3, etc., ECM, the Code 43 is typically a knock sensor fault code.
 

Etzler

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Jun 8, 2013
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I apologize for not posting the serial number. Serial Number OW698323. I failed to mention that the ECM (555), was replace by Simon Motorsports. Thank you for all the info. I will check everything and report back.
 

alldodge

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Your motor has two knock sensors which are attached on each side of the block under the exhaust manifolds. The wires which a blue coming from the sensors should not be tie wrapped, or follow the path of the spark plug wires. The firing of the spark plugs can be picked up by the wires and tell the ECM that there is a knock.
 
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