2006 Volvo Penta 5.7 GI limited rpms

[abbchevelle]

Hello folks.

Quick run down. Repowered from a 5.0 GXI to a 5.7 GI. Did buy ECM for 5.7. Also 5.0 ran great and as expected. So yes I broke a good running boat.
Using same wiring harness but as far as I can tell same harness between GI and GXI. FYI 5.0 setup was emmissioned for California.
5.7 starts and idles great sounds awesome in neutral. However when on water going it feels like power is being pulled out and it will only go to 4000 rpms and very slowly and I have to trim to get that. Very sluggish feeling. I have replaced almost everything with no change. List is this, new fuel pump, new tps and iac plugs wires cap and rotor. Cleaned screen on fuel regulator that wasn’t dirty. Bought 600.00 scan tool. Only things not changed at the moment is the map sensor, fuel regulator and cam sensor. FYI fuel pressure is 38-40 psi. I’ve done the injector test and all work as expected. 140-150 psi in every cylinder. Any direction would be appreciated before I switch it to carb. Lol.

 

[alldodge]

Welcome
Is timing advancing?

Fuel pressure is off. Later GXI are 50-60 psi, Gi is same unless it's a old model then it would be 30 psi

 

[abbchevelle]

So fuel pressure is fixed. Bad regulator. Problem still exist. Underpower with 4000 rpm max. Feels like your trying to push a mountain with not enough power. Timing is advancing. I’m goi g to do a little more this afternoon with the scannner and snap pics of timing adavance see if it retarding for some reason.

 

[Finseeker 268]

So fuel pressure is fixed. Bad regulator. Problem still exist. Underpower with 4000 rpm max. Feels like your trying to push a mountain with not enough power. Timing is advancing. I’m goi g to do a little more this afternoon with the scannner and snap pics of timing adavance see if it retarding for some reason.

Did you ever resolve this. I have a 268 with a 5.7GXI and experiencing the same problem.

 

[QBhoy]

Hello folks.

Quick run down. Repowered from a 5.0 GXI to a 5.7 GI. Did buy ECM for 5.7. Also 5.0 ran great and as expected. So yes I broke a good running boat.
Using same wiring harness but as far as I can tell same harness between GI and GXI. FYI 5.0 setup was emmissioned for California.
5.7 starts and idles great sounds awesome in neutral. However when on water going it feels like power is being pulled out and it will only go to 4000 rpms and very slowly and I have to trim to get that. Very sluggish feeling. I have replaced almost everything with no change. List is this, new fuel pump, new tps and iac plugs wires cap and rotor. Cleaned screen on fuel regulator that wasn’t dirty. Bought 600.00 scan tool. Only things not changed at the moment is the map sensor, fuel regulator and cam sensor. FYI fuel pressure is 38-40 psi. I’ve done the injector test and all work as expected. 140-150 psi in every cylinder. Any direction would be appreciated before I switch it to carb. Lol.

I’d have naturally thought the harness (along with a load of other things) would be different between these two. Have I got you right in thinking the new engine is a Gi or are you saying it’s a GL ? As far as I know, the Gi is a single point tbi and the GL is a carb. Your 5.0 GXi was likely an mpi more advanced thing altogether.

 

[QBhoy]

Welcome
Is timing advancing?

Fuel pressure is off. Later GXI are 50-60 psi, Gi is same unless it's a old model then it would be 30 psi

View attachment 382465

Hi AD…wonder why the fuel pressure is so different from the mercruiser version. Wasn’t aware of that until now.

 

[alldodge]

Hi AD…wonder why the fuel pressure is so different from the mercruiser version. Wasn’t aware of that until now.

That's like asking why person A like cabbage and person B does not. It's engineering thing and even I don't understand

 

[QBhoy]

That's like asking why person A like cabbage and person B does not. It's engineering thing and even I don't understand

Haha. Mmm. Maybe not so much…when person an and b are one and the same . Surely a vp 5.0 gxi is the same as a merc 5.0 mpi. Almost exclusively in its entirety, but certainly in terms of fuelling, you’d think. Unless they both have higher pressure in later days for some reason. Pretty sure my mpi and the engines like it, run about early 40’s psi usually.