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2000 Mercruiser 5.7 EFI no spark

S

stang32

Regular Contributor
i am trying to find a wiring diagram for this engine. i have a no start, no spark condition, the ignition sensor in the distributor is sending signal to the fuel injectors to fire when the distributor it turning but i get no spark. i hope its not the ecm, is the control module built into the ECM?

i have 12V at the coil and fuel coming from the injectors when the distributor rotor spins

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stang32 said:
i am trying to find a wiring diagram for this engine. i have a no start, no spark condition, the ignition sensor in the distributor is sending signal to the fuel injectors to fire when the distributor it turning but i get no spark.
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Welcome to ME.com!

Unfortunately, it doesn't don't quite work like that. Just like at the parts store, providing a serial number helps to accurate ID the engine and which set of components are used on it.

Do you know which version of MEFI controller is used? Do you know whether the Delco EST or the Thunderbolt-V distributor is used?

I doubt it is the ECU, unless somebody has induced a failure....most no-sparks are easy to fix but you need to know what ignition is used to get the correct troubleshooting procedure.

Finally, you can always disconnect the tach and check for spark....some tach failure mechanisms will prohibit ignition functions....
 
there is no serial #, i think the motor has been replaced at some point. it has the standard mercruiser distributor, with the 2 wires into the hall effect switch ( plus ground) like the thunderbolt

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" Finally, you can always disconnect the tach and check for spark....some tach failure mechanisms will prohibit ignition functions...."

HMM, the tach has been acting up, when 1st started the needle goeas around the clock backwards to idle speed.

 
from what I can see, a 2000 mercruiser 5.7 with a MEFI-1 or -2 controller using the TBI setup should have the EST distributor.....otherwise, there's no spark advance.....unless somebody stuffed a t-bolt-IV into it.....is there a separate ignition control module on the inside of the exhaust elbow?
 
The dist sends the spark to the correct cylinder and the module inside generates the pulse to provide spark, has nothing to do with the injectors,
Plus fuel injection uses a crank position sensor
 
well when i unbolt the metal plate from the rotor & put it back in the distributor & rotate it manually, through the hall effect switch the injectors fire,
 
bottom line guys go through the trouble tree, don't cut corners, the problem turned out to be a bad tachometer. the diagnostic chart goes through the basics & 1 of them is to check the grey wire sending signal to the tach, check for ground, short to ground, well sure as ****, the tach was shorted to ground internally, i disconnected it & the boat fired right up.
 
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