Dual fuel pumps

[WTRSK1R]

I will start this post by saying I do not have a clue how this is actually wired, but it would be very strange to have the ECM even involved. I always thought the fuel pump is set up to run to get a certain pressue in the line and when it hits that pressure it shuts off. If there are only 2 wires (as shown in your graphic) then that would mean the ECM is either monitoring fuel flow, fuel pressure, or just the engine operation. I recognize that it DOES monitor the engine, but it would seem odd to me that it would know that fuel pressue is low when monitoring the various engine sensors. Course as I said, I do not have a clue what is all being tracked in the newer engines with Cat Convertors.

In any case, congrats that this is all warranty, and hopefully it does not happen again, or to anyone else.

[bigmac]

well, i called the dealership yesterday to check on the boat. apparently, due to the zero off installation, the boat has a 2009 ECM and the dealer has no idea how to hook up the diagnostics to this one. i guess all new zero off boats will have this ECM. according to the dealer, they were able to hook up to the computer and the check engine code i was getting was "fuel pressure" related. this only confirms my above post that something in the ECM told the fuel pumps to increase fuel pressure which eventually blew both hoses. since this is an ECM issue, the MC dealer said it all is covered under warranty and i don't need the blown hoses for proof. they only problem now is that nobody is sure why the ECM did this and what needs to be done to either clear the code or make an adjustment in the ECM so it doesn't happen again.

What boat are we talking about here? You have an 89 listed in your profile.

Putting in ZeroOff requires a whole new ECM? That sounds like a recipe for trouble.

[JimN]

The fuel pump delivers the pressure it's designed for and the regulator determines what gets to the injectors. If what goes to the regulator is more than the motor needs, the return line sends it back to the tank. As long as the ECM gets RPM data, the pump is running. Sending fuel pressure info to the ECM is easy enough, with a pressure sensor.

The dual pump setup is factory installed?

[sk8salomon]

What boat are we talking about here? You have an 89 listed in your profile.

Putting in ZeroOff requires a whole new ECM? That sounds like a recipe for trouble.

'07 MCPS197 TT

its not that the zero off requires a new ECM, the boat did not come factory with ZO, only PP. ZO had to install an upgraded ECM due to the aftermarket install. all new '08 boats with ZO will have this ECM that my '07 has.

The fuel pump delivers the pressure it's designed for and the regulator determines what gets to the injectors. If what goes to the regulator is more than the motor needs, the return line sends it back to the tank. As long as the ECM gets RPM data, the pump is running. Sending fuel pressure info to the ECM is easy enough, with a pressure sensor.

The dual pump setup is factory installed?

yes, all the TT's come with the Mueller twin pump setup.

[bigmac]

'07 MCPS197 TT

its not that the zero off requires a new ECM, the boat did not come factory with ZO, only PP. ZO had to install an upgraded ECM due to the aftermarket install. all new '08 boats with ZO will have this ECM that my '07 has.

yes, all the TT's come with the Mueller twin pump setup.

Interesting.

So, does the ECM control fuel pressure in this dual pump setup? Or is the problem with your fuel pressure regulator?

Does this dual pump setup signal a MasterCraft departure from the apparently problematic in-tank fuel pump setup they have been using on all their boats?

[flipper]

Interesting.

So, does the ECM control fuel pressure in this dual pump setup? Or is the problem with your fuel pressure regulator?

Does this dual pump setup signal a MasterCraft departure from the apparently problematic in-tank fuel pump setup they have been using on all their boats?

It sounds like the ZO won't "talk" to the old ECM, so either the ECM was flashed to recognize the ZO, or a new one was put in. It doesn't sound like the ECM has any problem, just that he wanted ZO in his boat.

[bigmac]

It sounds like the ZO won't "talk" to the old ECM, so either the ECM was flashed to recognize the ZO, or a new one was put in. It doesn't sound like the ECM has any problem, just that he wanted ZO in his boat.

He's blown a couple of hose in his fuel system. It's not due to ethanol, so presumably it's due to excessive pressure in his fuel system. This factory Mueller dual pump setup is a departure from MC's usual in-tank setup. I'm curious about that. Likewise, I'm curious whether the excessive pressure is from an erroneous signal from the ECM, or erroneous performance of the fuel pressure regulator.

[sk8salomon]

Interesting.

So, does the ECM control fuel pressure in this dual pump setup? Or is the problem with your fuel pressure regulator?

I'd say more of a regulator problem than pump. I'm not sure how the regulator adjusts pressure signal to the pumps, like DC voltage or something?

This factory Mueller dual pump setup is a departure from MC's usual in-tank setup. I'm curious about that. Likewise, I'm curious whether the excessive pressure is from an erroneous signal from the ECM, or erroneous performance of the fuel pressure regulator.

This dual pump setup is still an "in-tank" assembly. There is a manifold "Y" piece that both pumps feed to, then outside the tank a single larger hose to the engine.

[JimN]

The regulator uses vacuum from the engine to vary the flow.

[Engine Nut]

He's blown a couple of hose in his fuel system. It's not due to ethanol, so presumably it's due to excessive pressure in his fuel system. This factory Mueller dual pump setup is a departure from MC's usual in-tank setup. I'm curious about that. Likewise, I'm curious whether the excessive pressure is from an erroneous signal from the ECM, or erroneous performance of the fuel pressure regulator.

All the ECM does is turn on the fuel pump. There is no device in the system to measure fuel pressure or regulate fuel pressure with the ECM. The fuel pressure is regulated at the pump with a mechanical regulator. I dont know much about the MC pumps but it looks to me like the regulator may be faulty allowing excessive pressure in the system that blew the fuel lines in the pump.

[Engine Nut]

The regulator uses vacuum from the engine to vary the flow.

The pump in tank systems do not use a vacuum biased regulator.They use a mechanical regulator and the fuel pressure stays constant al all RPM.

[sk8salomon]

The pump in tank systems do not use a vacuum biased regulator.They use a mechanical regulator and the fuel pressure stays constant al all RPM.

where is this mechanical regulator you speak of?

[JimN]

I guess I was thinking the regulator was the same as TBI and LT-1.

It's on the pump, right?

[Engine Nut]

I guess I was thinking the regulator was the same as TBI and LT-1.

It's on the pump, right?

Yes, it regulates at the pump. That is how we can get by with a single line from the pump to the engine. No more need for return lines from the engine to the tank.

[sk8salomon]

That is how we can get by with a single line from the pump to the engine.

we? hhmmmmm....engine nut must be an inside guy!