Bridgeport EFI charging system ?

[PoolGuy]

Hey all ...

Just rigged my Seebold Tunnel with a 91 Bridgeport EFI ... Motor runs strong, lots of power to 6k ... haven't had a chance to explore the upper RPM range yet due to a problem I'm having ... here's the deal ...

I CAN'T KEEP A BATTERY CHARGED ! ....

I get MAYBE 20 minutes from a fully charged battery and then the voltage drops to 12.5 and the ECU cuts out and the motor loads up and quits every time I lift the throttle ... I went through a few testing procedures, Stator resistance is 1.0 Ohm between the 2 yellow wires, and no continuity from either Yellow to ground, Rectifier failed it's test, so it got replace with a new one, and the problem persists ...

What are my options? Am I barking up the wrong tree with checking the charging system? ... I've read every thread on here with the word "Bridgeport" on it, and am aware that the charging systems suck, but really?, 20 minutes? ... seems a bit ridiculous ... Is their a special "low amp" fuelp pump I should try? ... will an aftermarket ECU help me out? ...

The battery always has enough Volts to crank the motor over, and it "usually" will restart easily (sometimes floods) ... I'm driving myself crazy with all the searching on here and electrical testing, who has some bridgeport experience they can offer?

Thanks in advance,

Jeff

[Eagle One]

Sounds like an ECU problem. Had the same thing with a 260 and it was the ECU. The voltage being 12.5 says your charging or it would be lower. Test at the battery with the engine off and running and see if you have a difference. If it's higher while running the charging system is working. Your tach would likely be out as well uif the rectifier was bad as it reads the signal there. Is it a Digital ECU or Analog?? Is the TPI working>?? Does it have one?? Suppose to. See some left off siometimes.

[PoolGuy]

Thanks for the response ...

I'll look into the ECU to see if it's digital or analog ... I do have a spare one ... I'll check the part #'s this weekend ... Not exactly sure how to test the TPI ... can't find that page of the service manual ... (don't have a manual, just some scanned copies of certain sections of the electrical chapter) Yes it has a vac TPI on the left side of the block with one vac line running to a T that goes to the horn and fuel pressure regulator I believe (from memory) ... vac line goes to P1, P2 is open to atmosphere ... their is a sensor at the top of the horn, however a block off plate is on the horn directly in line with the butterfly on the top side. As for the battery, after a good charge I get 13.5 V and the motor runs flawlessly for 15 minutes or so, then the problem starts ... Voltage has dropped to 12.5 ... back on the charger ... hence why I assumed charging system issue ... what should the voltage be at the battery at 3000 rpm or above? ... to test? ... Also, I'm looking into an Optima battery for it, anyone know which one best suits this application? torn between yellow and blue top.

Jeff

[luv2gofast]

Not exactly sure how to test the TPI ... can't find that page of the service manual ... (don't have a manual, just some scanned copies of certain sections of the electrical chapter)
Jeff
I have a manual if you need any other pages scanned.



Yes it has a vac TPI on the left side of the block with one vac line running to a T that goes to the horn and fuel pressure regulator
Jeff
That would be the MAP (Manifold Absolute Pressure) sensor. The TPI (Throttle Position Sensor) is on the butterfly shaft.



As for the battery, after a good charge I get 13.5 V and the motor runs flawlessly for 15 minutes or so, then the problem starts ... Voltage has dropped to 12.5 ... back on the charger ... hence why I assumed charging system issue ... what should the voltage be at the battery at 3000 rpm or above? ... to test? ...
Jeff
Those charging systems are pretty weak but I would think you should see 13.5 to 14v at 3000 RPM. You should for sure see the voltage go up when you rev the engine if it's charging. You can also take the red wire off of the regulator and put an amp meter between that red wire and the terminal on the regulator. You should see at least 5 - 6 amps while running, I think max is 14 so make sure the amp meter is capable of at least 20A. Another possibility is that there is corrosion somewhere between the battery and the ECU so it's not seeing the full 12.5 volts. Check the voltage from the red/yellow on one of the injectors to ground. That should be the same or very close to the battery voltage. If it's not look for a dirty connection.

Good luck and post your results,
Bob

[PoolGuy]

Thanks for the input Bob ... I'll test the voltage difference between the injectors and the battery

The TPI is what has been blocked off then, a common mod I assume? ... the round sensor above it on the upper half of the intake horn is still there ... the MAP sensor only has one vac line on it (P1) and P2 is open to atmosphere ...

The fact that it runs great on a fresh battery is what concerns me, and then turns into a bag of hammers that runs so rich it floods the motor ...

Seeing as the TPI has been blocked off, what other mods should I check for that are required to the wiring and/or vacuum lines to properly be removed? ... short of just unbolting the TPI ...

Thanks again to everyone supplying ideas for me ... keep 'em coming!

Jeff

[pyro]

If the TPI is un-hooked, then someone has likely upgraded it to a digital ECU.

My BP has a small rectifier, and NO regulator. It will drain the battery below 3000 RPM, and this is fairly normal.

[hst714]

If the TPI is un-hooked, then someone has likely upgraded it to a digital ECU.

My BP has a small rectifier, and NO regulator. It will drain the battery below 3000 RPM, and this is fairly normal.

how does it charge with no regulator? im not failiar with these charging sytems at all but i always thought it was like a motorcycle(which i am familiar with... which converts the ac off the stator to dc which then goes to the battery and charges it. i thought the regulator also kept the current at a consistent volatge... im looking into doing something for the charging system on my 260 i get a light day of boating out of it but i want to add a stereo and lights to my gauges, without adding a second battery.

[pyro]

The system is so small, it's essentially self-regulating, it can't hurt itself even at full power with a weak battery, and the rectifier still keeps the system isolated upstream from the battery, so it doesn't drain below cruise RPM, but it doesn't charge either. ;)

[luv2gofast]

I just looked at my BP book and it shows a regulator on the EFI but not on the carb version. That is the same as the fishing motors. A 200 doesn't have a reg but the 220 EFI does. On the BP it shows the regulator mounted to the top of the block right behind the threaded plug. It should have a red and yellow that go to the rectifier and black to ground. It says "If battery voltage is above 14.5V with engine running, replace regulator".

HST you are exactly right, AC from stator > rectifier makes it DC > regulator limits the voltage to about 14.5.