1990dtgl98
Seaman
- Joined
- Jul 17, 2011
- Messages
- 57
Hey everyone. So I have a 1999 mercruser 7.4L (L29) that I've been chasing a issue with it only being able to hit 3600 at WOT. It has new plugs and cap/rotor. I also replaced the fuel pressure regulator and pump. Stock props on bravo 3. 4 people, 20gal gas, no bottom buildup, 23' open bowrider. 3600rpm and 36mph is the most I can get out of it. Almost has a bit of a vibration like it's only running on 7 cylinders, and the hole shot I feel should be better for a 7.4 with a duo prop. Also smells slightly gassy running (could be in my head though).
I finally got a rinda after being out of stock for a while. I thought I could do a load test but apparently that's only mefi4. Might have to pull plug wires and see if 1 cylinder doesn't change.
Plugged in with key on engine off, I measured some parameters. Tps is .58v in neutral, and goes to 4v at wot but the throttle position says 82% open. Could this be causing the WOT issue? Throttle body looks fully open.
Here's what else I logged quickly at idle on earmuffs
IAC position: 82
IAC base pos: 82
Injector pulse width: 4.4ms
Map voltage: 2.13v
Manifold pressure: 14.8in
Is manifold idle pressure low?
I finally got a rinda after being out of stock for a while. I thought I could do a load test but apparently that's only mefi4. Might have to pull plug wires and see if 1 cylinder doesn't change.
Plugged in with key on engine off, I measured some parameters. Tps is .58v in neutral, and goes to 4v at wot but the throttle position says 82% open. Could this be causing the WOT issue? Throttle body looks fully open.
Here's what else I logged quickly at idle on earmuffs
IAC position: 82
IAC base pos: 82
Injector pulse width: 4.4ms
Map voltage: 2.13v
Manifold pressure: 14.8in
Is manifold idle pressure low?
