98 pre 2100 wt ECM failure... Help!!

[Talon2g]

I have a 98 that ran great on the lake last week but Sunday dumped it in the lake and could not get the engine to fire. After taking a look and listen I'm not getting the two beeps or fuel pump activation on the first key position. When I turn to start still no fuel pump, I checked the relays, fuses, breakers, ignition switch and it just keeps cranking with no fuel pump activation. I hard wired the fuel pump and it spins right up no problem. I replaced relay just for the heck of it getting power from main supply just not getting power from the ECM when I'm turning it over or on the first key position.
I have looked around for a new ECM #861265R6 which is the most recent superseded number can't find on anywhere no even in the boat grave yards. Mercury couldn't find one either.
Any help would be great the engine only has 350 hours and 30 was because I left the key on!
Can the ECM be repaired or am I just missing the big pink elephant in the boat?
Final note while sitting at the boat launch I tried a little shot of start fluid and it fired for a split second but then choked out. So I think I'm in the right place with the ECM at this point but maybe not!
Thanks for your experience and knowledge in advance!

[dom w. forte]

Before you replace the ecm you need to determine if the ecm is receiveing proper signals to turn on the relays , if its not seeing specific info such as key power ect, it wont turn on the relays , suggest the ecm be scaned and circut test.

[TeamAllen]

Not sure if you need a new ECM, but here is a company that has some and could possibly help you with your current one if needed.
http://www.obd2allinone.com/mefiecms.asp

Maybe borrow/rent or buy a fuel pressure gauge?

[Talon2g]

Thank you for the lead on the ECM I have a buddy coming over on Monday to test my ECM with a new machine he has. I searched all day yesterday to try to find an ECM and was coming up with nothing, it's just nice to know that I don't own a gigantic paperweight if it ends up being broken.

[lee]

Do you have a MEFI4?

[Talon2g]

I believe it is a MEFI1 but I'm not 100%

[Talon2g]

Correction to previous post, Lee I thought you were referring to the generation of the ECM my understanding is there are 4 and mine is the first. As far as my friends scan tool or PC he works for a company that has just recently launched a product that will scan ANY motor and diagnose. He has already used it on my dads Johnson outboard and detected the exact cause of the problem. But I don't anything about his gear! I checked a few more things last night but got no further. Everyone keeps saying doubt it is your ECM but no one can suggest what to check next or what direction to look at! So frustrating it's a nice weekend I'd love to be on the lake!

[boatwakes]

WAIT!!!!!! Check the 90amp square fuse at the starter battery cable connection!!!!! The fused side provides power to the ecm. It's the shape of a small square about 3/4" and it's white. One end will be connected to the starter battery post and the other with be the fused end connecting the ecm power cables and such. Also check your push button red circuit breaker on top of the motor. You should have either a MEFI 1 or a MEFI 2 ECM, neither one is available but Arizona Speed and Marine carry some that are re-flashed up to MEFI3.

[TeamAllen]

I suggested measuring your fuel pressure, but maybe you've already done that?

[Talon2g]

Already checked the 90amp functioning fine. there is no fuel pressure because the fuel pump doesn't come on because the relay that activates it is not activating although it is grounded and powered.thanks for the suggestion keep them coming it would make me so happy to know I missed something I would rather it not be a hard to find expensive ECM but it's looking that way!

[Talon2g]

Can you explain more About the differance in the ECM and if a 3 will plug and play with my engine? Also going back to check the 90 amp I don't remember checking more then 1 terminal there for power!
Thanks

[boatwakes]

Pull the 90 amp and test it for continuity. However, it may still show some but not the ability to carry amperage so as a confirmation, remove it, mark the wires that were on it, move them all to the starter battery post and then try. If it goes, get a new fuse.

[IDBoating]

there is no fuel pressure because the fuel pump doesn't come on because the relay that activates it is not activating although it is grounded and powered.

If the relay coil is grounded on one side and powered on the other, and the relay isn't engaging, you have a bad relay. You said above that you hardwired the fuel pump and it works, so this may be as simple as a bad relay. When you say the relay is "powered", what do you mean exactly? What happens if you hardwire the relay coil? (Disconnect it from everything else first!) If you don't get a "click" then swap in a new relay.

More: When you hardwired the fuel pump to power and it ran, did you try starting the engine? Should be OK to run the fuel pump continuously for a short time, as the fuel pressure regulator should maintain constant pressure. This would be an easy further test to narrow things down.

Report back!

[Talon2g]

Yes ran the engine with the fuel pump hard wired. had prime engine and fill fuel filter because the fuel pump was having problems priming after a changed it and hadn't got it started after the change. I am also not getting the 2 warning beeps on the accessory switch which I read today is directly controlled by the ECM. When I disconnected it from the harness and grounded it the thing consistently beeped. In regards to the 90 amp fuse I will give it a try and see what happens for some reason that ECM is just not activating that fuel pump relay. It's beyond me I guess!!! Ps replaced relay already and swapped the two and the one that didn't work before worked on the main power relay and the one that worked on te main power did not work on the fuel relay!

[IDBoating]

Yes ran the engine with the fuel pump hard wired.

That suggests that much is working properly, because otherwise the engine wouldn't be able to run at all.

Ps replaced relay already and swapped the two and the one that didn't work before worked on the main power relay and the one that worked on te main power did not work on the fuel relay!

Good diagnostics, you've proven that both relays are functioning and the problem is the one servicing the fuel pump isn't being driven properly. Have you put a meter on the coil voltage? I had a Mercury ECU-controlled engine a while back that started having fuel rail problems. Short version is that the driver transistor in the ECU was starting to fail. In this application the fuel pump was hard wired to +12VDC on one side, and the ECU pulled the other side to "ground" (really, a couple of volts above ground) - in other words a typical low-side switching transistor circuit (NPN or N-channel). The transistor was no longer pulling the low side of the fuel pump low enough, so the voltage across the pump motor wasn't high enough, so insufficient current was flowing through the motor, so it couldn't maintain fuel rail pressure under high demand.

Replacement ECU's were breathtakingly expensive, and besides: The ECU was still trying to control the fuel pump. Why not use that signal and just amplify it? My solution was to wire in a sealed automotive relay (could have used a low RDSon MOSFET but relays are easier to understand if someone else ever has to work on it). Instead of having to pull +12VDC nearly to ground while passing many amps, this meant the ECU's driver only had to create a sufficient differential to exceed the relay coil's pull-in voltage - always a much lower number than the coil's rated voltage - and do so while passing a few tens of milliamps, which in turn meant the differential was lower (and thus better). The relay then switched the low side of the fuel pump directly to ground, which meant the +12VDC rated fuel pump was now seeing BETTER conditions than even from a brand-new ECU. Voila - rail pressure stabilized and the engine worked great again. Problem solved for about $10 in parts and an hour of time.

The point of all this is that you need to measure and understand what is actually happening at the fuel pump. If the ECU is trying to control it but failing, and detecting that failure, you may be able to fix the whole thing with a little creativity.