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1999 Magnum EFI no start

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crazy T

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Working on a 1999 Magnum 200 EFI cranks but will not start has spark looking to see if anyone can provide what the fuel pressure should be for the injectors also how can I test to make sure the ECU is sending the signal to operate the injectors?

Thanks in advance T.
 
crazy T said:
Working on a 1999 Magnum 200 EFI cranks but will not start has spark looking to see if anyone can provide what the fuel pressure should be for the injectors also how can I test to make sure the ECU is sending the signal to operate the injectors?

Thanks in advance T.
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If it cranks, add some fuel and see if it wants to run. If it does, check the fuel pressure and flow rate.

You can use a multimeter to test the signal from the ECM but you could also use test devices called 'noid lights'.

Do you see the tach needle move when you crank it?

I did a search and someone who had repowered their boat with the same engine mentioned 36lb fuel pressure, so you could use that as a starting point.

Where is your safety lanyard?
 
Yes if i add fuel in the butterflies it will fire, the fuel pressure is at 36 psi key on, the RPM gauge doesnt move suspect it is bad the lanyard is in the run position.
 
Thanks Fatz fuel pressure is in range next step is to disassemble the FMS and test for signal to injectors, located in Acworth, GA
 
crazy T said:
Yes if i add fuel in the butterflies it will fire, the fuel pressure is at 36 psi key on, the RPM gauge doesnt move suspect it is bad the lanyard is in the run position.
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And you have the toggling safety switch, rather than the button that's pressed in? If it's the button type, check the purple wire on any gauge- if there's no 12V on it, bypass the safety switch.

Look further into the lack of tach signal- if the ECM doesn't see RPM, it won't fire the injectors.
 
Yes its the toggle switch, ok thanks will investigate the RPM gauge i have one I can temp wire up to see if guage or something else. Thanks!!!!
 
crazy T said:
Yes its the toggle switch, ok thanks will investigate the RPM gauge i have one I can temp wire up to see if guage or something else. Thanks!!!!
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It's the RPM SIGNAL that means something although I would also find out where the tach gauge comes from- if it's the coil, disconnect the gauge and if it starts, the gauge is likely grounding the gray wire- that was a cheap & easy way to prevent cars being stolen in the 1960s and 1970s- wire the tach to the body of a car, through a switch as a kill switch.

Ideally, you can consult a manual to see the wiring diagram and learn the ignition system. It has injection, so it needs a way to send RPM info to the ECM and with a distributor, it's often the Ignition Control Module but some use a crank or cam sensor. I don't have a Mercruiser manual for this.
 
Look further into the lack of tach signal- if the ECM doesn't see RPM, it won't fire the injectors.
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This is not correct as ECU get its signals from the switchboxes..tach signal does not go thru ECU
 
After further trouble shooting found starboard side no spark on those three cylinders, Port side has spark read thru some other posts and switched the red n blue wires with the red / white and blue / white on switch boxes only port side continues to have spark any help would be appreciated.
 
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