2004 115 EFI Problems

I have a pair of 115 EFI four strokes and one engine is giving me fits. It starts and idles fine. After between 15 and 30 minutes of cruising one engine looses power and starts to sputter. If I pull the throttle back to neutral it idles fine but will not throttle up. If I turn off the key and wait ten seconds the engine restarts and works fine for another 10 to 30 minutes or longer and then does it again. I have replaced all the fuel lines and bulbs and even swapped the lines from one engine to the other but the same engine has the problem. I have also swapped the low pressure fuel pump with the same results. The dealer has taken the fuel system apart, cleaned the injectors and all associated parts in the system with no success. He is stumped and so am I.

Re: 2004 115 EFI Problems

What did the Mercury Diagnostics indicate?

Re: 2004 115 EFI Problems

Timestep said:

What did the Mercury Diagnostics indicate?

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They told me unless they can duplicate the problem there is nothing they can do. Otherwise nothing appears to be wrong.

Re: 2004 115 EFI Problems

If there is a electrical/sensor problem the ECM will store it as a trouble code like a OBD1 system. It sounds like a IAC problem as its resets we you turn key on/off...

Re: 2004 115 EFI Problems

Faztbullet said:

If there is a electrical/sensor problem the ECM will store it as a trouble code like a OBD1 system. It sounds like a IAC problem as its resets we you turn key on/off...

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What is IAC. I don't want to go back at them and not know what I am talking about.

Re: 2004 115 EFI Problems

Idle air control...

Re: 2004 115 EFI Problems

What I did not mention is I am in Mexico and if you have ever been hear you would know that they are not very advanced and they don't have computer readers. I have been looking at a diagnostic reader on the internet and will probably have to buy one and do my own checks. Appreciate the help though.

Re: 2004 115 EFI Problems

Go to a dealer with a diagnostic reader, it will save money in the long run!

Dave

Re: 2004 115 EFI Problems

It does not take a DDT tester to read this engine , you just need to order the 91-884793A1 test harness($35USD) if it was a earlier model you can use a 12volt test test light as you just count the flashes anyway.
http://www.crowleymarine.com/parts/304666.cfm

Re: 2004 115 EFI Problems

Well I finally killed it today! Will not reset with the key. Backs down to 2000 rpm and if I don't try to advance the throttle it runs for a little bit and then loads up. From what I have read I am assuming it is shutting down two cylinders. I will be putting the rig away for the summer and picking up a Rinda diagnostic reader while in the states. Thanks for all the input. I did call Mercury yesterday and was given real bad information on my first call. The first gentlemen told me that according to my serial numbers I had a 90 and a 115 motor. I then rechecked my serial numbers and called back with the same information and got a gal who told me I definitely had two 115 motors and even gave me the manufacture month. Call was to verify the ECM that I found on the engine which looks different than the one on the Rinda info sheets and was different than the part number given in the parts manual. I am real disappointed with this engine and Mercury (both service and info from the company) which has been a problem from day one. The mate engine has never given me a lick of problems. Lets hope it gets better next fishing season!

Re: 2004 115 EFI Problems

It is a pain, and trice as much time and effort, but you could try swapping components between motors, when the problem switches motors, BINGO!

As Fazt has pointed out, start with the IAC.

Curious, when the motor slows pull the lanyard to kill it but DO NOT turn off the key, reclip the lanyard and do a spark test on all cyls to see if you have lost spark on one or more cyls. You may be able to determine if this is an ignition or EFI problem.

Re: 2004 115 EFI Problems

Pull the lanyard! This is a pair of 115's on an ocean boat!!!

Re: 2004 115 EFI Problems

I got the diagnostic reader and there are no recent faults stored in the ECM. I am now back to thinking its a fuel problem given the crap fuel I get here in Mexico. Could plugged or partially plugged injectors act the way I have described? If I am loosing fuel pressure because of a clogged fuel pump filter would I get a fault code?

Re: 2004 115 EFI Problems

Well I think I have found the issue. I opened up the Fuel Vapor separator and it as well as the lines exiting the separator and the fuel pump filter is full of a gritty brown and black material that looks like a fine sand. All of the filters prior to the separator are clean including the filter from the gas tank, the filter before the mechanical fuel pump and the screen in the mechanical fuel pump. After an internet search I found an article that says the fuel in the separator can boil during a drop in fuel pressure under acceleration because the vapor separator is so close to the engine block with no protection. this causes the suspended particles and minerals in the fuel to fall out of suspension and eventually clogging the system. They recommend placing a reflective heat shield between the separator and the block. Problem solved! Take notes all you mechanics out there as this appears to be a big problem in the US with many fuel injected engines particularly with ethanol blended fuels. Down here in Mexico the fuel is not very sophisticated and not as refined as the US so the problem is prevalent especially with the warm waters.

Re: 2004 115 EFI Problems

Well I think I have found the issue. I opened up the Fuel Vapor separator and it as well as the lines exiting the separator and the fuel pump filter is full of a gritty brown and black material that looks like a fine sand. All of the filters prior to the separator are clean including the filter from the gas tank, the filter before the mechanical fuel pump and the screen in the mechanical fuel pump. After an internet search I found an article that says the fuel in the separator can boil during a drop in fuel pressure under acceleration because the vapor separator is so close to the engine block with no protection. this causes the suspended particles and minerals in the fuel to fall out of suspension and eventually clogging the system. They recommend placing a reflective heat shield between the separator and the block. Problem solved! Take notes all you mechanics out there as this appears to be a big problem in the US with many fuel injected engines particularly with ethanol blended fuels. Down here in Mexico the fuel is not very sophisticated and not as refined as the US so the problem is prevalent especially with the warm waters.