leaky MAD EFI

[specboatops]

I noticed that on my MAD EFI after I shut down from even an idle and say I trim up a little like I'm going to anchor for a while, it leaks fuel out and puddles up on the transom area of my boat. IS this normal? if so how much is normal? is this and indication of some other problem? does this mean its running to rich ? Any thoughts are appreciated.


Chris

[Stitch King]

Most of it is likely condensation and some fuel is possible due to reversion. The aluminum gets cold due to the air flow over it and it sweats like a cold drink glass would. The fuel in the condensation mix seems to be caused by the Batch Firing of the Injectors if it's a 3 liter. When I went full sequential firing the injectors, the drool that came out of mine is now only water.

[skydog]

Yea way to rich! I bet if you trim her all the way down she smokes like mad and almost stalls. I know you have good reeds. (rubber coated right?) 260 air horn and call Tony!!!!

Skydog P.S. Call Tony now!!!! :) :)

[specboatops]

Keep Em Coming, My Head Hurts From Trying To Figure This Out, Its A 2001 2.5 Steel Sleeve Motor Ported To 260 Specs, Yes Rubber Coated 5 Pedal Reeds, Chest Work, Rod Slots, New Everything.........

[skydog]

Did your MPG drop big time buddy? From your old motor?

Skydog

[specboatops]

Did your MPG drop big time buddy? From your old motor?

Skydog

HUGE DROPYEA TO SAY THE LEAST, DROPPED FROM WHEN i WAS RUNNING THE HORN ON HER...

[skydog]

Right on that should tell you what you need to know right there buddy!

Skydog TTT

[skydog]

What do the piston tops look like? I bet money they are clean zero carbon. All the fuel is just washing clean.

Skydog

[skydog]

If the Mad uses a TPS look at that too! Not sure if it does or not?

[RBT]

HUGE DROPYEA TO SAY THE LEAST, DROPPED FROM WHEN i WAS RUNNING THE HORN ON HER...


This is becasue the MAD intake doesn't hold vacuum like the plenum on the Merc air horn does. Your ECU is pouring a lot of fuel to the motor as it thinks you are accelerating all the time.

RT

[skydog]

Right on!!! I say get a Merc. 260 air horn and Tonys Pcu!! You will be in love with your boat again!!! :) :)

Skydog

[specboatops]

THANKS FOR THE REPLY'S, IT HELPS ME TRYING TO FIGURE MY NEXT MOVE ( WHICH I'M ABOUT TO START THE WHOLE THING ON FIRE:reddevil::reddevil:)

I GUESS IT IS NOT ( MAD EFI) THE SMARTEST THING TO GO WITH FOR LAKE AND RIVER USE :confused::confused: IT DOES HAVE A TON MORE MID RANGE TO IT, BUT I CAN'T IDLE WORTH A CRAP DOWN THE RIVER, OR START IT VERY EASY, I NEED TO HOP IN THE BOAT AND PUSH ON THE FOOT THROTTLE TO START IT, WHERE BEFORE I COULD REACH IN AND HIT THE KEY AND SHE'D FIRE RIGHT UP........

[twig]

The Twin's are still at MAD ring and ask them.

[1BadAction]

if you arent running an adjustable ECU with them, expecting it to work correctly is like pissing in the wind. IMO.

[6Killer]

So, it sounds like you are using a MAD 3 horn intake and a Mercury ECU?

That is a bad combo for lake riding. Just like RBT says, the 3 hole intake doesnt make much vacuum and will not operate a Merc ECU at low speed. A Gold SVS/Merc ECU combo would do the same thing, run like crap at low speed.

You can reprogram your Merc ECU to work with the MAD 3 holer, but it has to be done by someone with the software and they have to be with you to see how the boat reacts to the changes they make. RBT has access to this software.

A step in the right direction would be for you to have RBT put the A13 program in your ECU if you have an A6 or any other. Wouldnt be perfect, but it would be better. At that time, he could check your ECU to see if the map sensor is functioning correctly. The MAP (manifold absolute pressure) sensor tells the ECU where the throttle is. It reads vacuum between the reeds and the throttle plates, no vacuum = wide open throttle, lots vacuum (relative) = throttle closed.

[RBT]

I have little experience with the Mad intake, but I would think that you could also pickup vacuum with the averaging vacuum setup from Merc.

[skydog]

Is the mad like the SVS on the vacuum? The ecu only sees vacuum from two cyls and not all six? Plus there is no vacuum chamber to speak of. On my SVS i gun drilled the plate to get more vacuum(all 6 cyl) still not enuff.(remeber that Steve H.?) Put the air horn on and tonys pcu and never looked back!
Skydog

[specboatops]

Someone correct me if I'm wrong here, but I thought it had MORE vacuum than the horn, that was one of the bragging points Mr. Wayne Taylor use to make???

[specboatops]

This is becasue the MAD intake doesn't hold vacuum like the plenum on the Merc air horn does. Your ECU is pouring a lot of fuel to the motor as it thinks you are accelerating all the time.

RT

Wouldn't excelleration create vacuum???

[skydog]

No Vacuum is at idle or a little above. When the buttler flys are open you have zero vacuum. What RBT means is the ecm thinks you are not at idle so it is adding lots more fuel. I had the same problem with the SVS! Killer mid ok top end pig rich down low.

Skydog

[specboatops]

I think all I need to fix this is a match :reddevil::reddevil:

[1BadAction]

I think all I need to fix this is a match :reddevil::reddevil:

nah, just ship the intake to me. :D I'll even pay the UPS bill. :reddevil:

[RBT]

There should always up until a steady full rpm is attained be some vacuum, the key is to have enough that the ECU can read it... or the ECU set to compensate.
It is the holding of steady rpm for lake use that really screws with the ECU, it DUMPS fuel to the motor, wash's pistons and makes the motor four stroke, But as soon as you give the motor more air to burn the fuel you have already given it.... away you go!.

Anyhow, it can be made to work. PCU or a mod 849849 box.


Skydog, all new SVS's are gun drilled for vacuum averaging. The old setup with no check valve was giving the SVS pulsing vacuum, the updated to the check valve which helped a little, then to the Merc style 3 point averaging, with the gun drilled chambers.

[specboatops]

GREAT INFO THANKS FOR THE HELP, 1BAD I WAS ALMOST READY TO SHIP IT TO YA, ONLY IF YOU'D STOP PICKING ON PYRO .......:eek:;)

[RBT]

If you don't send it to me I will start picking on Pyro!

[1BadAction]

GREAT INFO THANKS FOR THE HELP, 1BAD I WAS ALMOST READY TO SHIP IT TO YA, ONLY IF YOU'D STOP PICKING ON PYRO .......:eek:;)


If you don't send it to me I will start picking on Pyro!

either way Pyro is screwed. :eek: LOL.

[specboatops]

either Way Pyro Is Screwed. :eek: Lol.

Lol :d:d:d:d

[skydog]

ha ha Right on guys!! :) :) ((Skydog, all new SVS's are gun drilled for vacuum averaging.))

That is cool but the stock air horn still work the best for me and i had alittle more top end speed with it! Tonys PCU was a MUST for my set up with the SVS or stock air horn!

Skydog

[RBT]

SVS, just hits harder than a airhorn, better mid range pull... nothing up top.

[skydog]

Thank you RBT i know you know your Sh-t!!!

Skydog

[Tony Brucato]

Besides having enough vacuum, it's important to have a stable vacuum signal too. The Mercury ECU has a virtual accelerator pump, as does the PCU.
When the vacuum signal fluctuates wildly at low and mid RPM, the ECU thinks that you're pumping the throttle constantly and it dumps extra fuel at every event.
I would recommend that you put a vacuum fitting on each intake runner and plumb them to a common vacuum log or chamber. Use the largest fittings and hose that you can here, and this will act like a small plenum.
Add a couple of small orifice (.030") vacuum fittings to the vacuum log to route to the ECU and fuel pressure regulator. This will further reduce vacuum fluctuations

[Tony Brucato]

SVS, just hits harder than a airhorn, better mid range pull... nothing up top.

There will most certainly be more on top when the runner length and fuel delivery is set up correctly.

[jphii]

So Tony, this is basically what you were telling me yesterday?

[Tony Brucato]

Yes Joe, this is what we would have to do to your motor to use the PCU.

[skydog]

Just get Tonys PCU and be done with it!! :) :) :)

Skydog

[RBT]

Just get Tonys PCU and be done with it!! :) :) :)

Skydog

LOL, there is some truth to that. But you still need to have stable vacuum for the PCU to work well. After that the PCU is better than the Merc box, it's ease of adjustability, and that is has 24 rpm points over the 16 of Merc.... both of which are better than the Mad, which batch fires 3 injectors at a time, only giving you left and right speration over the 1-2, 3-4, 5-6 of the PCU/Merc.

[rpm racing]

Besides having enough vacuum, it's important to have a stable vacuum signal too. The Mercury ECU has a virtual accelerator pump, as does the PCU.
When the vacuum signal fluctuates wildly at low and mid RPM, the ECU thinks that you're pumping the throttle constantly and it dumps extra fuel at every event.
I would recommend that you put a vacuum fitting on each intake runner and plumb them to a common vacuum log or chamber. Use the largest fittings and hose that you can here, and this will act like a small plenum.
Add a couple of small orifice (.030") vacuum fittings to the vacuum log to route to the ECU and fuel pressure regulator. This will further reduce vacuum fluctuations

I find it interesting that you can say all this and yet still argue that a vacuum based accelerator pump for the ECU is BETTER than a TPS sensor which works perfect everytime once set up???? Not to mention that 2 stroke vacuum pull is weak at best and virtually zero once you open the throttle a 32nd of an inch.

Have you ever wired in a TPS in place of the vaccuum sensor in a PCU?? That would be the set up, other than you would most likely have to rewrite the fuel map (actually redesign the fuel map table) to get the full potential.

[rpm racing]

LOL, there is some truth to that. But you still need to have stable vacuum for the PCU to work well. After that the PCU is better than the Merc box, it's ease of adjustability, and that is has 24 rpm points over the 16 of Merc.... both of which are better than the Mad, which batch fires 3 injectors at a time, only giving you left and right speration over the 1-2, 3-4, 5-6 of the PCU/Merc.



Really it is just a "6 or half dozen" scenario, both system have there weak links.

The 280 motorola set up really offers hands down the best....it just needs to get tuned for race use and have the ignition issues taken care of.

[RBT]

Really it is just a "6 or half dozen" scenario, both system have there weak links.

The 280 motorola set up really offers hands down the best....it just needs to get tuned for race use and have the ignition issues taken care of.

"Better".... the motorola still has a weak ignition side, so Better again is Motec, there is no correct answer here.
Realistically for the average guy, the PCU is the best there is. Even for advanced guys it is hard to beat the PCU/Merc box.

[Tony Brucato]

I find it interesting that you can say all this and yet still argue that a vacuum based accelerator pump for the ECU is BETTER than a TPS sensor which works perfect everytime once set up???? Not to mention that 2 stroke vacuum pull is weak at best and virtually zero once you open the throttle a 32nd of an inch.

Have you ever wired in a TPS in place of the vaccuum sensor in a PCU?? That would be the set up, other than you would most likely have to rewrite the fuel map (actually redesign the fuel map table) to get the full potential.


I don't think that my advice discredits my preference for a MAP sensor. I was just describing one way of building a useable vacuum signal compared to the vacuum signal he has now.
If he was using a TPS based system but had a ceiling fan switch hooked up with duct ape and bailing wire, I would advise him how to properly hook up a TPS instead.
BTW, Mercury has used the MAP sensor based ECU on many of their motors without use of a TPS, but I can't think of any Mercury EFI engines that use a TPS and not a MAP sensor also.

I've spend many hours analyzing vacuum/load profiles and can tell you that you're way off base with your description of two stroke engine vacuum.

[Liqui-Fly]

That's a whole lot of explaining for the simple fact that the MAD unit injects in front of the reeds. It is a great drag racing intake and gives lots of midrange but you will puddle up when the foot is down during lake use.

[specboatops]

Lots And Lots Of Good Reading, Thank You Rbt, Skydog, Tony B. And All That Have Responded, Gives Me Something To Sleep On Tonight.

[RBT]

That's a whole lot of explaining for the simple fact that the MAD unit injects in front of the reeds. It is a great drag racing intake and gives lots of midrange but you will puddle up when the foot is down during lake use.

Fly, injectors infont of or behind the reads, doesn't make a difference to the ECU, it reads no vacuum. It pours fuel to the motor, making for horrible fuel mileage, and in this case it pools fuel. Some simple plumbing and a PCU/ ECU change can fix everything.