Problem with 5.7 gxi 2006

muc

"Retired" Association of Marine Technicians...
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Jul 7, 2004
Messages
2,259
Re: Problem with 5.7 gxi 2006

Yes 15psi seems high --- one of the reasons I recommended swapping the fuel cells from motor to motor.
5.7Gi-B→F low 8psi ? 4pressure , high pressure 50 – 60psi


Volvo serial number search says 7743372 for engine mechanical and 7742218 for EFI diagnostics
But I feel Volvo EGC manual 7743614 works better for this engine.
 

doadonut12

Cadet
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Apr 9, 2014
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14
Re: Problem with 5.7 gxi 2006

Thanks guys, been busy getting everyone's boats ready for spring here and haven't had that boat back on the rack yet. will bring it back next week i hope and will hopefully figure it out. i did check the vacuum hose and it was fine. i thought 15 psi was high as well...crappy part is i dont have my "donor" boat anymore...haha....may need to look for another.
 

doadonut12

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Apr 9, 2014
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Re: Problem with 5.7 gxi 2006

so i got the boat back on the rack. tried fuel cell, no change. i did pull the screen out of the regulator and that actually did bring my pressure down for 60 to 52, and low side down to almost 10 psi. so i thought for sure that was it....nope same thing.

so like i said with the IAC reset, the boat dies when you do the reset, either a new or the old IAC. im leaning toward maybe a harness problem or something because once i get the boat cranked and idling, i can disconnect the IAC, and shut it off and it will crank every time....even as i type this i went back down to the boat and she cranked back up with the IAC disconnected.....and thoughts?
 

Fun Times

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9,240
Re: Problem with 5.7 gxi 2006

Try running the test on page 251 on the first link below to see what you come up with. Using your test light hooked to ground, unplug the IAC connector and check all 4 wires to see if they are blinking. One wire should blink first then automatically the ECM will switch to the next wire and make it blink x 4. Repeat the test a few times. Carefully wiggle the harness wires around and at ECM connectors while testing.

Click on the attachment then open it up for test tree info of the IAC.
http://forums.iboats.com/volvo-pent...-volvo-penta-5-7-gi-e-573644.html#post3948092

Also here's a different perspective of the IAC as an refresher if interested. Yes it's for a car, but the info helps with the understanding of the working system.:)
4 Ways to Check an Idle Air Control Valve - wikiHow

Step 5 in ^^^ is a test you may want to try.
Use a test light if the idle speed did not do what it was supposed to. Hook it up to the idle air control solenoid and watch the light. The light will either flash or become dimmer for the four circuits if the valve is at fault. If it doesn't, it means the wiring or the computer (powertrain control module) is bad.
 

wrench 3

Commander
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Aug 12, 2012
Messages
2,108
Re: Problem with 5.7 gxi 2006

I'm puzzled by the interest in the IAC. It could cause the necessity to manually open the throttle to get it running, but it wouldn't make it over fuel.
Were all your sensor readings good when cranking. A wiring fault "should" show up in the readings. Not sure what your manual shows, but most give .8 ohms maximum resistance in a ground circuit. But I've ran into problems with lower resistance than that.
 

doadonut12

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Apr 9, 2014
Messages
14
Re: Problem with 5.7 gxi 2006

Ok cool will look at those. just to fill you in i took the old IAC and ground one side of it flat, kinda like a D shape....cranks everytime...i know this doesnt fix it but just a test i did on my own.
 

doadonut12

Cadet
Joined
Apr 9, 2014
Messages
14
Re: Problem with 5.7 gxi 2006

I'm puzzled by the interest in the IAC. It could cause the necessity to manually open the throttle to get it running, but it wouldn't make it over fuel.
Were all your sensor readings good when cranking. A wiring fault "should" show up in the readings. Not sure what your manual shows, but most give .8 ohms maximum resistance in a ground circuit. But I've ran into problems with lower resistance than that.

I do need to manually open the throttle to crank the boat, if i dont it soaks the plugs. all sensors are good, like i said once its running its fine.....getting it to crank is the trick.
 

wrench 3

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Aug 12, 2012
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Re: Problem with 5.7 gxi 2006

If all it takes is a higher IAC flow, the bad sensor will not be a glaring fault, especially if its the MAP. Since you've already swapped out the sensors, it sounds like its time to start testing individual circuits.
 

wrench 3

Commander
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Aug 12, 2012
Messages
2,108
Re: Problem with 5.7 gxi 2006

Getting into a crank sensor problem reminded me of something. When the sensor pattern degrades they often become a spike instead of a square wave. Some times you get a double spike. The extra spark that close together won't affect the ignition but may mess up the RPM reading to the ECM.
Do you have a scope to check the sensor pattern?
 
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