92 Bridgeport lost power, idels, but won't plane

[rwalla]

My 86 Vector/EFI Bridgeport was running along. I had just installed a XR-6 lower unit and the boat was porpoising some (not adjusted yet) when it suddenly lost power and came off plane. The engine starts and idles fine, and just a little past idle is fine. When I tried to accelerate and get back on plane it "stutters", no matter what I do with the throttle. I have a bosh pump. I unhooked the out fuel line and routed it back into the tank, turned it on (with relay) and it sent a stream into the tank. It looked like it would squirt about one foot horizontally. I have a cheap filter just prior to the pump. I know that that was a bull**** kind of test, but everything was working fine until the moment it died. The engine characteristics are similar to engines I have worked on (non-marine) that were not getting the ignition timing advanced. What is the best way for me to proceed? Can I get an inline fuel pressure gauge? What do I look for? If it is not fuel related, does the ecm control the advance? How do I check it? I think I can have someone squirt a little fuel into the bell (under load) to test if the problem is a fuel delivery issue. Remember that this problem started suddenly while the motor was working properly.
Thanks for your support. Richard

[transomstand]

I'd be lookin at the stator, sounds like it lost the high side.

[Superbender]

Welcome to Scream and fly,we're going to need more info

[rwalla]

Thank you. I did not think of a stator issue that would allow the motor to idle fine and not allow it to rev. I will look into testing that.

Richard

[wrechin2]

Thank you. I did not think of a stator issue that would allow the motor to idle fine and not allow it to rev. I will look into testing that.

Richard
Here you go. It starts about 3/4 of the way down. You will see there is a test for won't rev past 3K. I have seen them bog at 2500 due to a stator.
222941

[pyro]

The wire connections on the switchbox can also corrode under the insulation, and the cowling can bump into them and fatigue the wires. I has a similar problem on mine that turned out to be a wire broken under the insulation, an inch away from the connector head. Pull gently on each one. If there's a bad one, the insulation will strrrretch when you tug on it.

[rwalla]

Thank you all for your assistance. I found two bad yellow wires from the stator, replaced stator with a new one. Then a bad switch box was causing the #3 cylinder to fire almost constantly. That cylinder is low on compression now (around 100psi). I got the boat to get up on plane for about 1 minute and then it started loosing power and will only idle. I bought a new bosch pump and two filters. I am having the fuel injectors cleaned and flowed. I will report if it helps. I don't want to fix cylinders until I have worked out the other bugs worked out. Any suggestions?
Thanks Richard

[rev.ronnie]

Does the BP have the same vacuum signal port to the ECU as a 260? If so, those get plugged and won't provide a good signal.

[rwalla]

Ronnie: I've replaced most of the vacuum hoses, but there is the one coming out of the back of the ECU. It looks O.K. but I will check that next. Just got the fuel injectors flowed, reinstalled and will re-test.
Thanks for your help. Richard

[pyro]

It's not the hoses that cause the trouble, it's the little bronze elbow fittings where they connect to the intake manifold-- They get plugged up with gummy fuel residue. I learned this first-hand. Poke them out with a guitar string or piece of tag wire.

[rwalla]

Pyro:

I would not have checked the elbow fittings. I would have just replaced the hose. That's the kind of pro insight I needed to get. I will get this blasted thing going again. Thanks for the tech advice. Richard

[rev.ronnie]

That's what I meant by the vacuum signal port. I hear about them getting plugged all the time. Use a good injector cleaner with every fill. Sea foam seems to be popular. I use Synergen.

[rwalla]

I have replaced fuel pump, stator, switch boxes, and cleaned injectors. I'm firing on all 6. The Throttle Position Sensor spikes to about 5 volts at a certain spot about 1/3 of the way open. Otherwise the sensor rises the voltage slowly as it opens to that spot and after that spot. The boat will now get up on plane but when I back off full throttle, the motor begins losing power, comes off plane, continues idiling but will not again rev or make enough power to get back up on plane. Would a faulty TPS cause the computer to go into a default mode that would cause these types of problems?

Thanks Richard

[pyro]

It's possible. This is why myself and many others have gone to the Brucato box, with its own intake vacuum sensor on-board, and no external TPS required. Worth every penny. :)