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Jason, Marine Mechanic
Category: Boat
Satisfied Customers: 15684
Experience:  Degree in Marine Technology. Gas and diesel marine mechanic.
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Having hard time figuring out est 1 open on my mercruiser.any

Customer Question

having hard time figuring out cod est 1 open on my mercruiser.any ideas?
Submitted: 2 years ago.
Category: Boat
Expert:  Jason replied 2 years ago.
Hello my name is ***** ***** am I speaking with? What is the serial number on your engine. Which scan tool are you using to pull the code? There should be a 3 digit code, can I get that code number?
Customer: replied 2 years ago.
Hi Jason, my name is ***** ***** the merury mercruiser Rinda scanner.Enigne Serial # ***** 3 diget # ***** est 1 open and says code is active.Which got as far to figure out pcm to ign coil #1 circuit is open.Swapped coils,opened up harness to ohm out wires so far...Also cant seem to erase code to see if something else pops up also.Trying to figure out which wire is #1 circuit so I can check it??????
Expert:  Jason replied 2 years ago.
Hi Miro. Are you using the handheld scanner, or Diacom, the laptop program? Also, are you an outboard tech or inboard tech only? Do you have outboard troubleshooting tools? (Like a Stevens spark checker?)
Customer: replied 2 years ago.
hand held scanner.I am an auto tech by trade.I own outboard and this I/O
Expert:  Jason replied 2 years ago.
Gotcha. Now if you clear the code how quickly will it return? How well does the engine run?
Customer: replied 2 years ago.
IF you can id that wire for me it would be great start,I will trace it saving some time.Sure I can figure it out just want to expedite things...That's just it I cant seem to clear CODE. Tried by scanner,disconnecting batts,Is there another way?
Expert:  Jason replied 2 years ago.
Disconnect the harness from the ECM and the ignition coil. Look for the white with a dark green stripe wire. Do you show continuity on that wire between the ECM and coil? If yes, switch over to resistance, what does the resitiance read?
Customer: replied 2 years ago.
The engine seems to be good at times,Than when I hold steady at 3000rpm less or above it sounds like running out of gas.will drop it to idle than try to accelerate will not be smooth.sounds like running out of fuel,get sevral pops out of TB unit than may clear up. I am doing these tests out of water on Rabbit Ears the rectangle ones.I thought off dropping it in somewhere and trying but I would rather be more convinced it will perform well.This boat is new to me,Never used it.Enigine shows 61 Hrs.Just little history for u.I think the est circuit can create such chaos as did in the auto field but I maybe baring up the wrong tree.
Expert:  Jason replied 2 years ago.
I think we posted at the same time, see my above message.
Customer: replied 2 years ago.
That was what I was going to ck according to my common sense.Will ck and let u know in a few
Customer: replied 2 years ago.
coil to ecm no continuity,however from the little 4 pin module on the coil bracket that same color wire to the ecm connector does.I think I have an idea where were going with this but trying not to open up more harness.Are those the same wires?Is there another test other than opening harness?
Customer: replied 2 years ago.
My issue is I don't have the exact schematic for my engine.I have the flat dist cap distributor with a 3 wire sensor inside and no module like I see listed on what I have availiable.I remember the est circuits being within those modules.This distributor with not sure what that switch is,is talked about as that thing is usually in open mode.Also heard that mercruiser had some wiring harness problems...Maybe this is one of them???
Expert:  Jason replied 2 years ago.
That white/green runs from pin 23 on the ECM harness over to pin B on the coil harness. That is the trigger wire from the ECM to the coil driver. You should definitely have continuity so if you don't, you have a broken wire. It's only that 1 wire on the circuit so you can come 6 to 8 inches off the ECM and cut the white/green, and then do the same on the coil end. And then splice a new wire in between the two and you shouldn't have any more problems. Does that make sense to you?
Expert:  Jason replied 2 years ago.
Good morning, just checking in. Any progress?
Customer: replied 2 years ago.
Hi Jason,sorry I wasn't able to get back to you.Yes that was what I was thinking about running new wire but little confusion on white and green stripe.There is white and light green and white and dark green.The l green runs from coil to module or coil driver as u refer to which looks like an older gm module inside a distributor.That is why I am assuming there is no continuity at pin 23.Now the dark green striped wire goes from driver to 23.You indicated which I understood from Ign coil which is the light green stripe not the driver.So is there another run somewhere to the ecm that makes a direct run I can ck or another suggestion?
Expert:  Jason replied 2 years ago.
I am talking about the white/dark green wire.
Customer: replied 2 years ago.
There is continuity there.

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