700sci motor dying - 42 Fountain lightning
08-26-2014, 09:09 PM
#22
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Location: Oak Creek, Wisconsin
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Did your mechanic change BOTH fuel filters on that one engine, the LOW pressure big screw on filter AND the SMALL high pressure filter?
My boat had one high pressure filter plugged badly after high pressure pump went bad, boat would only go 104 and would trip "low fuel pressure" warnings.
SmartCraft Race Edition showed fuel pressure on that engine lower than other side, and went down at high speed/boost, did NOT boost compensate up (can see the delta P from boost and fuel pressure, very neat that Smartcraft!")
Changed low pressure filter, AND high, can see the HP filter and it was clogged with black coating and could hardly blow thru it at all, fuel just sat in it, hard to believe it went as good as it did with that,
Thinking on that you'd likely get low pressure warning and your prob is low speed AND low power so very low fuel flow, still, make sure he changed both filters to be thorough.
The boats have neutral and reverse rev limiter, so in neutral won't rev high, hits rev limiter.
There is shift interruptor too, to retard timing/cut power for split seconds while shifting; shifts much better with torque flow interrupt.
Did you try swapping ECU's from the other engine to see if it still happens, and if the OTHER engine runs FINE with the "problem" engine's ECU?
Did you use Smart Craft to check fuel pressure from side to side, all the motor stats to see if anything odd vs the "good" engine's numbers?
My boat had one high pressure filter plugged badly after high pressure pump went bad, boat would only go 104 and would trip "low fuel pressure" warnings.
SmartCraft Race Edition showed fuel pressure on that engine lower than other side, and went down at high speed/boost, did NOT boost compensate up (can see the delta P from boost and fuel pressure, very neat that Smartcraft!")
Changed low pressure filter, AND high, can see the HP filter and it was clogged with black coating and could hardly blow thru it at all, fuel just sat in it, hard to believe it went as good as it did with that,
Thinking on that you'd likely get low pressure warning and your prob is low speed AND low power so very low fuel flow, still, make sure he changed both filters to be thorough.
The boats have neutral and reverse rev limiter, so in neutral won't rev high, hits rev limiter.
There is shift interruptor too, to retard timing/cut power for split seconds while shifting; shifts much better with torque flow interrupt.
Did you try swapping ECU's from the other engine to see if it still happens, and if the OTHER engine runs FINE with the "problem" engine's ECU?
Did you use Smart Craft to check fuel pressure from side to side, all the motor stats to see if anything odd vs the "good" engine's numbers?
08-28-2014, 04:51 AM
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Well an update , the problem is not yet solved !!
When we remove the iac and test on the good engine , it works , exchanged PCMs and still works on the good engine , the good IAC and good PCM are not running good on the new engine .(the Good IAC is NOT responding on the bad engine)
At 1500 rpm the good supercharger is whinning and the other is not ! can it be some supercharger sensor ? Boost valve ?
changed both fuel filters and injectors , checked wires ??
We are out of ideas ?? Any help
Any help ??
When we remove the iac and test on the good engine , it works , exchanged PCMs and still works on the good engine , the good IAC and good PCM are not running good on the new engine .(the Good IAC is NOT responding on the bad engine)
At 1500 rpm the good supercharger is whinning and the other is not ! can it be some supercharger sensor ? Boost valve ?
changed both fuel filters and injectors , checked wires ??
We are out of ideas ?? Any help
Any help ??
08-28-2014, 08:01 AM
#29
Check the resistance across the two leads on both IACs, they should not be 0 Ohms. I would be very careful swapping parts back and forth because a failed IAC can damage the ECU. When you find your bad IAC replace it and then check all of the fuses in the black fuse holder on the back of the engine. The IAC and boost bypass are on the same circuit and you will probably find that one of the 20 AMP fuses are blown which is causing your performance issue.
Don't replace the fuse without checking/replacing the IACor you could damage the ECU. This is a very common problem of these engines.
GF?
Don't replace the fuse without checking/replacing the IACor you could damage the ECU. This is a very common problem of these engines.
GF?
