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First time poster...hope I'm doing this right. Thank you for being here. First the question, then some info.
Question: What might be causing a new engine block to have trouble powering to full strength, but otherwise running smoothly.
Info:
1. Engine is a 1996 PCM 351 Windsor with GT40 heads and EFI multiport fuel injection. 2 winters ago, extended freeze cracked block and exhaust manifolds. Purchased rebuilt block from reputable dealer. Completed replacement recently. I was initially not getting fuel pressure and found information where hose connecting the high pressure pump to rail feeders sometimes cracked...I opened fuel cell...the hose did have a crack and replaced the hose. After, measurements on rail were good. In my opinion, my EFI pressure at shaeffer valve seems good. My pressure gauge is working intermittantly (connection), but sometimes it seems like gauge is not pushing in the schaefferr pin. When it does, we get approx 40 psi pressure...possibly dropping to 36-37 during running. I am going replace the gauge today to verify it is not interrmitant pressure vs intermittant gauge.a
2. After getting EFI working correctly (?) this week, ran great in driveway several times with hose hooked to intake. Presumed we were home free and took to lake yesterday. It started and ran great out of the marina until we passed the no wake sign. I thottled to take off and it would only go to approx 2200 RPM...about enough to get planed and nothing more. We did try to use the pressure gauge to try and bleed air from injector rails. We did get more power as we discharged from the schaefferr valve, but not completely...I think we got up to about 2600. We do not know if a complete disconnect of EFI cell / Rails, etc will put air in rails and cause my problem, top end accelleration.
3. One more thing...when preparing Friday night before going to lake, we started again. right before starting, my son said the valve to run water was open, but he did not open it more than a small turn. The motor ran for, I don't know, two to three minutes. I started sensing hot, looked at temp gauge...saw it 3/4 to top...turned off engine...immediately went and opened valve...let water go through for a couple of minutes, until gauge was down...then ran a little more...it seemed to run fine. Also at the lake, there were not sounds or abnormalities other than the lack of top end power. I have since read that I should look at water pump impeller as it may have melted...but the impeller seemed to work fine at lake as we had no cooling issues.
4. From what I have read, possibilities may be (1) Distr Cap/Rotors/Wires. (2) Fuel Pump (If I'm getting 40 at rail, can I dismiss this?), (4) Hi Pressure Fuel Cell Filter placement (it is in bottom of fuel cell with fuel pump down in the hole at center of the filter), (4) Timing Set, (5) Throttle Cabling not right (I did examine this a bit...even pushed trottle all the way and then pushed where the cable ends to the full open position).
5. Wondering if the running without water could do damage that would let the enginie run normal at lower speeds, but when I kick it up, some loss of compression limits my high end ability to run.
6. Last, above my air intake is a device that my advisors called the plenum...and a flame arrestor. When we took boat apart, the flame arrestor had stuff like old dirt caked on outside...like a dirty air filter. I brushed this a bit and tried to clean it. Now, I hear air sucking through the metal filter area. Is that a possible problem?
In the end, I am relatiively inexperienced at engines, but feel like I've taken on a major project, got to the finish line, but lack only high end power...trying to provide enough relevant detail in hopes for advice on what is most likly to cause the issue I am having. I am also hoping for some comfort that if the boat ran fine afterward, just no high end power, that my Friday night hot running event didn't blow up my engine before I even put it in the water.
Thank you in advance for any advice available.
Question: What might be causing a new engine block to have trouble powering to full strength, but otherwise running smoothly.
Info:
1. Engine is a 1996 PCM 351 Windsor with GT40 heads and EFI multiport fuel injection. 2 winters ago, extended freeze cracked block and exhaust manifolds. Purchased rebuilt block from reputable dealer. Completed replacement recently. I was initially not getting fuel pressure and found information where hose connecting the high pressure pump to rail feeders sometimes cracked...I opened fuel cell...the hose did have a crack and replaced the hose. After, measurements on rail were good. In my opinion, my EFI pressure at shaeffer valve seems good. My pressure gauge is working intermittantly (connection), but sometimes it seems like gauge is not pushing in the schaefferr pin. When it does, we get approx 40 psi pressure...possibly dropping to 36-37 during running. I am going replace the gauge today to verify it is not interrmitant pressure vs intermittant gauge.a
2. After getting EFI working correctly (?) this week, ran great in driveway several times with hose hooked to intake. Presumed we were home free and took to lake yesterday. It started and ran great out of the marina until we passed the no wake sign. I thottled to take off and it would only go to approx 2200 RPM...about enough to get planed and nothing more. We did try to use the pressure gauge to try and bleed air from injector rails. We did get more power as we discharged from the schaefferr valve, but not completely...I think we got up to about 2600. We do not know if a complete disconnect of EFI cell / Rails, etc will put air in rails and cause my problem, top end accelleration.
3. One more thing...when preparing Friday night before going to lake, we started again. right before starting, my son said the valve to run water was open, but he did not open it more than a small turn. The motor ran for, I don't know, two to three minutes. I started sensing hot, looked at temp gauge...saw it 3/4 to top...turned off engine...immediately went and opened valve...let water go through for a couple of minutes, until gauge was down...then ran a little more...it seemed to run fine. Also at the lake, there were not sounds or abnormalities other than the lack of top end power. I have since read that I should look at water pump impeller as it may have melted...but the impeller seemed to work fine at lake as we had no cooling issues.
4. From what I have read, possibilities may be (1) Distr Cap/Rotors/Wires. (2) Fuel Pump (If I'm getting 40 at rail, can I dismiss this?), (4) Hi Pressure Fuel Cell Filter placement (it is in bottom of fuel cell with fuel pump down in the hole at center of the filter), (4) Timing Set, (5) Throttle Cabling not right (I did examine this a bit...even pushed trottle all the way and then pushed where the cable ends to the full open position).
5. Wondering if the running without water could do damage that would let the enginie run normal at lower speeds, but when I kick it up, some loss of compression limits my high end ability to run.
6. Last, above my air intake is a device that my advisors called the plenum...and a flame arrestor. When we took boat apart, the flame arrestor had stuff like old dirt caked on outside...like a dirty air filter. I brushed this a bit and tried to clean it. Now, I hear air sucking through the metal filter area. Is that a possible problem?
In the end, I am relatiively inexperienced at engines, but feel like I've taken on a major project, got to the finish line, but lack only high end power...trying to provide enough relevant detail in hopes for advice on what is most likly to cause the issue I am having. I am also hoping for some comfort that if the boat ran fine afterward, just no high end power, that my Friday night hot running event didn't blow up my engine before I even put it in the water.
Thank you in advance for any advice available.
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