merc 5.7 L EFI Spark plug does not receive power

T

tlomb

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:mad: Hello, I am new to the forum. Sorry, my english is not too good, specially on mechanical matters, not native speaker.

Merc 5.7L EFI
Problem: Computer doesn?t send power to the spark plug, so spark plug doesn?t sparkle, and engine does not start. Engine does start if we give power to it directly.

I will be glad to receive any help. Thanks!
 
Don S

Don S

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Re: merc 5.7 L EFI Spark plug does not receive power

Welcome to iboats.
We need to have the Merc serial number from your engine.
 

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T

tlomb

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Re: merc 5.7 L EFI Spark plug does not receive power

Thank you for your reply, I will check SN this afternoon and post it.

Regarding problem, checked with computer scanner and said problem was TPS (throttle position sensor) Bought a new one, put it on, still not work, and scanner still says problem on TPS. Wait for any help!!! Thanks.
 
Don S

Don S

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Re: merc 5.7 L EFI Spark plug does not receive power

tlomb said:
Regarding problem, checked with computer scanner and said problem was TPS (throttle position sensor) Bought a new one, put it on, still not work, and scanner still says problem on TPS. Wait for any help!!!
Click to expand...

The TPS has nothing to do with spark. Stop throwing parts at it. There is probably something else that is causing your spark problem, and causing other things to happen.
 
JWebber

JWebber

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Re: merc 5.7 L EFI Spark plug does not receive power

Try disconnecting the battery to reset the trip code on PCM. But yea TPS would not cause a EFI to not send spark. it can be a CPS Crank position sensor, which sends a signal to PCM to shut down the ASD relay circuit to engine for spark at coil or coils.
 
Don S

Don S

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Re: merc 5.7 L EFI Spark plug does not receive power

Try disconnecting the battery to reset the trip code on PCM.
Click to expand...

That's a car thing, not marine. Won't change a thing.
He also may not have a CPS.
Just wait till he posts some ID info, then you don't just throw out useless information.
 
JWebber

JWebber

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Re: merc 5.7 L EFI Spark plug does not receive power

So marine EFI engines don't run in open and closed loop modes?? How are the codes stored in the computer, if and when all power is losted at the computer stored memory? How does it stay there? Just asking! Igintion sensor maybe?
 
Don S

Don S

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Re: merc 5.7 L EFI Spark plug does not receive power

New topic please, in the non repair IO forum.
 
T

tlomb

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Re: merc 5.7 L EFI Spark plug does not receive power

Hello! Here is the information:

Model MCM 5.7L EFI
Engine Serial Number OK163806

If we give a little touch of power to a violet/purple wire (socket/plug of 4 wires) the engine will start. When we stop engine and try to start it the normal way it wont start. The socket/plug I am talking about is the wire harness that goes into the distribuitor.
Glad to receive help! thanks!
 
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