Will Simoneaux
Recruit
- Joined
- Jun 3, 2013
- Messages
- 1
1996 PCM Windsor 351 w/ GT 40 Heads and Multiport EFI
Question: What might be causing older Performance engine with new engine block to have trouble powering to full strength, when otherwise running smoothly?
Data points:
2 winters ago, extended freeze cracked block and exhaust manifolds. Purchased rebuilt block and manifolds from reputable dealer. Recently completed installation of rebuilt engine. Past week, ran great in driveway several times with water hose hooked to cooling system. Presumed we were home free and took to lake yesterday. It started and ran great out of the marina?s no wake zone. I full thottled take off and imagine my disappointment when it would only go to approx 2200 RPM...about enough to get planed and nothing more. It?s like someone put a governer on the motor to make it a smooth but boring ride!
Fuel Pressure: Bought pressure gauge and tested EFI. Getting 40 psi at schaefer valve on rail. This makes me think to look elsewhere. Two other tidbits: (1) I didn?t get to test if pressure dropped as I went full thottle. Will try that this weekend on the water. (2) I think this is a distractor, but will mention anyway. We were uncertain if air in injector rails would degrade performance. So we did a bleed at schaefer valve?surprised we got a small, but detectable pickup on performance?it kicked up to about 2600 RPM and we got a little pickup in power?not sure if this is important or not.
Throttle / Linkage: I did check throttle linkage to verify connected and fully engaging the thottle body. It was. Then I removed the Flame arrester so I could look at actual flapper valve on inside of throttle body and verify it was opening 90 degrees. It was.
I have put new plugs in before taking out. Have not changed rotor/cap/plug wires. Hesitate to do that now before I eliminate other more likely issues (the motor is running so clean, I don?t think I?m having problems there).
My sense is that either I need to have timing set and/or there is something happening with computer management of fuel / air / ignition mix that I won?t be able to find.
Anyone who has advise on this would be very much appreciated. Thank you.
Question: What might be causing older Performance engine with new engine block to have trouble powering to full strength, when otherwise running smoothly?
Data points:
2 winters ago, extended freeze cracked block and exhaust manifolds. Purchased rebuilt block and manifolds from reputable dealer. Recently completed installation of rebuilt engine. Past week, ran great in driveway several times with water hose hooked to cooling system. Presumed we were home free and took to lake yesterday. It started and ran great out of the marina?s no wake zone. I full thottled take off and imagine my disappointment when it would only go to approx 2200 RPM...about enough to get planed and nothing more. It?s like someone put a governer on the motor to make it a smooth but boring ride!
Fuel Pressure: Bought pressure gauge and tested EFI. Getting 40 psi at schaefer valve on rail. This makes me think to look elsewhere. Two other tidbits: (1) I didn?t get to test if pressure dropped as I went full thottle. Will try that this weekend on the water. (2) I think this is a distractor, but will mention anyway. We were uncertain if air in injector rails would degrade performance. So we did a bleed at schaefer valve?surprised we got a small, but detectable pickup on performance?it kicked up to about 2600 RPM and we got a little pickup in power?not sure if this is important or not.
Throttle / Linkage: I did check throttle linkage to verify connected and fully engaging the thottle body. It was. Then I removed the Flame arrester so I could look at actual flapper valve on inside of throttle body and verify it was opening 90 degrees. It was.
I have put new plugs in before taking out. Have not changed rotor/cap/plug wires. Hesitate to do that now before I eliminate other more likely issues (the motor is running so clean, I don?t think I?m having problems there).
My sense is that either I need to have timing set and/or there is something happening with computer management of fuel / air / ignition mix that I won?t be able to find.
Anyone who has advise on this would be very much appreciated. Thank you.