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  1. #1

    Default 1994 5.0 Cobra EFI stuck at 25% power

    I have a 1994 Four Winns with a 5.0 EFI OMC(Ford) Cobra Engine. The boat starts fine and runs well in neutral, even up to 5000 RPM. When I put the boat in to gear and attempt to take it to WOT the engine will not exceed 2500 RPM and is getting no power to get it up on plane. There is minor backfire if I open the throttle up all of the way. It seems to me like a fuel problem but I have checked most points of the fuel system. I have been replacing parts and spending way too much money to keep guessing at the problem. Gas pressure is ok at WOT. I have done the following:

    Replaced the fuel pump
    Blown out the fuel lines
    Replaced the alternator
    replaced starter relay
    checked fuel pressure

    I have been told that the issue could be in the timing, so I removed the distributor to replace the pick up coil. Have not been able to disassemble the distributor(maybe another post), but their is minor corrosion on the old coil. Could that be the problem. If that does not fix it I plan on opening up the engine to adjust the timing chain. Has anyone experienced similar problems. Please HELP!! I can feel the minutes of the summer slowly sweating away as I sit in this greasy hole.

  2. #2

    Default Re: 1994 5.0 Cobra EFI stuck at 25% power

    I highly doubt that whoever told you that it was timing meant that it was valve timing. They probably meant igniton timing. The only way valve timing would be off is if it was apart at one point and put back together a tooth off, and hopefully it would have been cought right way. Just check the ignition timing first. It's way easier. Could be a bad coil too. Take it off and check the specs with a volt-ohm meter. Don't throw parts at it. That's never the way to do it. There is ALWAYS a way to check a part before you just go out and buy a new one. Well... almost always.
    2000 Chris Craft 240 Bowrider
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  3. #3
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    Default Re: 1994 5.0 Cobra EFI stuck at 25% power

    check the ignition timing with a timing light. sounds like it may be "retarded" meaning the spark is occurring after it should. corrosion on the pickup coil isn't good either. a small amount of parts cleaner squirted onto an old toothbrush should be able to brush it all off without damage. re install distributor correctly, check timing with timing light, adjust as necessary.

  4. #4
    Rear Admiral JustJason's Avatar
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    Default Re: 1994 5.0 Cobra EFI stuck at 25% power

    Sounds like your stuck in "fail safe" mode... or what ever OMC called it. Try disconnecting your water temp switch and oil pressure switch and see if any 1 of those brings the power back.
    just because you found it that way... doesn't mean it's supposed to be that way.

    Part of diagnostics is spending time figuring out not only what the problem is, but also sorting through what it isn't.

    The older the engine is, the chances of it having more than 1 problem goes up exponentially

    Boating has always been a rich mans hobby. Buying a new boat gets cheaper every year, but the maintenance, the repairs, and the overall cost of ownership of a boat has never gotten any cheaper.

  5. #5
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    Default Re: 1994 5.0 Cobra EFI stuck at 25% power

    I have the same engine in a Larson, and i am as frustrated as you are. I have a completetly rebuilt engine with all new fuel injection components, and i still have the same problem. The ignition system is also new new distributor new coil, new TFI module wires plugs you name it. I have tried disconecting the oil pressure swicth, and coolant temp sensor to the SLOW fail safe mode and it has not changed at all. I did run the boat this weekend, and i did notice that at one point the engine just decided to accelerate to 4000 rpm at WOT. Then it would not. Could it be a Computer Issue or wiring with the computer?

    CAN ANYONE OUT THERE HELP US?

  6. #6
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    Default Re: 1994 5.0 Cobra EFI stuck at 25% power

    Can anyone out there help us out. There are several of us on the Forum that have this same problem, and we have not been able to come up with a solution. Thank you in advance

  7. #7
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    Default Re: 1994 5.0 Cobra EFI stuck at 25% power-PLEASE HELP SEVERAL OF US NEED HELP!

    Does anyone out there have experience with these 5.0 EFI ford engines? How do we test for this issue. I have replaced everything, but the computer, and still the same problem!

  8. #8

    Default Re: 1994 5.0 Cobra EFI stuck at 25% power

    OK, so I had not checked the fuel pressure as I just replaced the pump. I hooked up a pressure gauge and the pressure ran at 30 PSI dropping down to 28-29 PSI at WOT. Could this be my problem why I am not getting power past 25%

  9. #9
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    Default Re: 1994 5.0 Cobra EFI stuck at 25% power

    Your fuel pressure is not the problem. I have the same exact issue with my engine, and cannot figure out why it is running like this. WE HAVE SOME COMPUTER RELATED PROBLEM. SO FAR I HAVE NOT HAD ANY LUCK REPAIRING IT. FORD ESPECIALIST OUT THERE PLEASE HELP!

  10. #10
    Rear Admiral JustJason's Avatar
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    Default Re: 1994 5.0 Cobra EFI stuck at 25% power

    the 2 of you guys should get together and split the cost of a manual.
    just because you found it that way... doesn't mean it's supposed to be that way.

    Part of diagnostics is spending time figuring out not only what the problem is, but also sorting through what it isn't.

    The older the engine is, the chances of it having more than 1 problem goes up exponentially

    Boating has always been a rich mans hobby. Buying a new boat gets cheaper every year, but the maintenance, the repairs, and the overall cost of ownership of a boat has never gotten any cheaper.

  11. #11
    Rear Admiral Maclin's Avatar
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    Default Re: 1994 5.0 Cobra EFI stuck at 25% power

    ...and once the manual is in look up what sensors would put it into reduced power mode (low oil pressure, coolant water flow too low, etc...)...


    Disconnecting sensors and/or wires may do the exact wrong thing as far as what will make the computer think all is ok and just keep it in failsafe mode, you need to bypass/test it however the manual says to check the sensor. I'm just sayin'.....

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    Default Re: 1994 5.0 Cobra EFI stuck at 25% power

    I have two manuals for this engine. a Seloc & the factory Volvo\OMC manual. there is little information in either manual about this SLOW fail safe system. There is a wiring diagram for the sensors, which i have already checked. My wiring and sensors are OK. The manual tells you that the computer will not store a service code for this system. It seems that there is no info in the manuals about this condition.

  13. #13
    Rear Admiral JustJason's Avatar
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    Default Re: 1994 5.0 Cobra EFI stuck at 25% power

    The seloc manuals good for a kneepad at best....
    I thought it was 95 for VP/OMC... not 94... so are you sure you have the correct manual for your engine? On most MEFI engines there is a manual for the engine and a manual for the MEFI system and you need both.
    So first we need it ID exactly what ya got. Can you post your model and serial ##'s for us?
    just because you found it that way... doesn't mean it's supposed to be that way.

    Part of diagnostics is spending time figuring out not only what the problem is, but also sorting through what it isn't.

    The older the engine is, the chances of it having more than 1 problem goes up exponentially

    Boating has always been a rich mans hobby. Buying a new boat gets cheaper every year, but the maintenance, the repairs, and the overall cost of ownership of a boat has never gotten any cheaper.

  14. #14
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    Default Re: 1994 5.0 Cobra EFI stuck at 25% power

    My engine is a 1994 OMC Ford EFI/ Volvo penta SX. I have the correct factory manual from volvo. it comes with separate books for each system ie: ignition, Fuel injection ect. I have gone through the entire manual and have not come up with a solution. We both have the exact same issues with these engines. Any help you can offer will be greatly appreciated.

  15. #15
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    Default Re: 1994 5.0 Cobra EFI stuck at 25% power

    Have you had any luck repairing the problem?

  16. #16
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    Default Re: 1994 5.0 Cobra EFI stuck at 25% power

    Four winns Have you been able to repair your engine? If so please share the info we all need the help.

  17. #17

    Default Re: 1994 5.0 Cobra EFI stuck at 25% power

    I still have had no luck, resorted to taking the boat out at 25% power for the entire weekend. How are you so sure that it is not a fuel pressure problem when the gauge is reading 30 psi? I am out of ideas, was hoping that you would come up with a solution as I dont know where to go next.

  18. #18
    Fleet Admiral HT32BSX115's Avatar
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    Default Re: 1994 5.0 Cobra EFI stuck at 25% power

    Howdy,

    Sorry to hear about your problems. The 94 and a couple of other years of the EFI/electronic IGN Cobras are now "Dinosaurs". Some parts are either not available or so expensive it's just not worth trying to fix them.

    Doug Russell for example wants more than $250 per injector!! (8 required)

    The Module (OMC 3854889) is more than $1000


    Your best bet might be to find a carb, manifold and distributor for it. Just replacing the injectors and ECM could cost more than a replacement engine.

    It might be nice to have all of it work but you could probably find a used 5.7l carbed engine for less than fixing the EFI 5.0 and never have to worry about it again.


    Just another option.


    Cheers,


    Rick


    73 de Rick
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    I use xxx oil and have never had a problem........
    1987 FourWinns 211 Liberator, 7.4L- Bravo III installed by ME,
    Formerly OMG 460 King Kobra powered
    1947 Stinson 108-2 Station Wagon
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  19. #19
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    Default Re: 1994 5.0 Cobra EFI stuck at 25% power

    THe 1994 OMC\VOLVO PENTA 5.0 engine was on of the best engines that an american manufacturer made at the time.it was certainly better that the GM power plants with their troublesome throtle injection or tuned port injection. The engine is extremely popular with the 5.0 mustang crowd. so much so that it has created an entire industry of aftermarket parts for those engines. you can get most of the engine parts from an regular ford dealer or NAPA.except for the marine starter and alternator. I was able to replace many of the parts on my engine at a fraction of the price. if you need the part numbers send me a private message and i will give you the ford part numbers. you do not need a new computer. the problem is not with your computer, and if you did need a new computer i found a company on the web that sells them for around $200. Do not get rid of one of the best most fuel effecient engines just TO GO BACK TO A GM MOTOR WITH A CARB.THAT IS GOING BACK TO THE DINO AGE.


    I have the same engine, and i was having the exact problem with my engine. I was finally able to fix it last weekend. The problem was in the wiring that goes to the distributor from the main engine harness. I checked the connector that connects the distributor to the main harness, and found that there was a purple wire with black stripe that had cracked insulation, and it was rubbing next to the ground wire that is next to it on the harness. I checked that ground wire, and it was not getting a proper ground. The ground wire does not have any insulation on it. on my engine it is just a bare wire. You can check that wire for a ground by using a test light connected to the battery positive. I removed the tape on part of the harness and spliced a new wire to that ground, and connected straight to an engine ground. I attached it to the bolt that holds the starter solenoid to the engine bracket. I took the boat out yesterday, and now it gets up on plane and revs up to 4500 rpm at WOT. Check this out before you spend thousands at a shop.

  20. #20
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    Default Re: 1994 5.0 Cobra EFI stuck at 25% power

    bY THE WAY I CHECKED THE FACTORY MANUAL, AND IT SAYS THAT AT IDLE THE ENGINE SHOULD HAVE 39 PSI. plus or minus 3 PSI. and at WOT IT SHOULD GO DOWN TO ABOUT 35PSI plus or minus 3 psi. check the operation of your fuel pressure regulator, and check the distributor wiring that i outlined in the previous post. the balck and purple wire that i mentioned is the wire that send a signal to the TFI moudule which controls ignition timing advanve and secondary spark output to the plugs. i hope you are able to fix it. keep us posted.

  21. #21

    Default Found The Problem On Mine....its Fixed.....

    Check for exhaust restrictions. I had the same symptoms. Removing the exhaust elbows, I discovered one flapper valve missing. I scoped the crossover tube but couldnt see anything in there. Removing the drive and looking in the transom bracket where the exhaust bellows connects, I could see the missing flapper valve stuck up flat against the opening, restricting exhaust flow. had to break the valve in two pieces to get it out but that fixed it.

  22. #22
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    Default Re: Found The Problem On Mine....its Fixed.....

    Disclaimer: never worked on an OMC/Ford 302 EFI engine, all of this comes from general Ford 302 SEFI experience, which I know this system is based on. If any of this data is wrong, I apologise. Also, please be aware this stuff assumes that there is a supply of known clean fuel, clean fuel filters, and good ignition parts in place. It also assumes that there are no other obvious problems such as the busted exhaust flapper thing mentioned above. Check that stuff before poking and prodding at the EFI junk, since more often than not, its not going to be the problem.

    When checking the timing on a typical injected Ford motor, there is a connector that must be unplugged to set the base timing. Usually its right next to the distributor in the harness going to the TFI module. If these use a remote mounted TFI ignition module (looks to be the case judging by the pic of the distributor) it will be near the TFI module. Connector is a small black thing with two wires on it. Unplug it, and set the base timing to factory specs. Timing marks are stamped into the balancer, may need to wire brush them to find it. Do not use the groove on the balancer, its unrelated to setting the timing. Also be sure you're on the BTDC side of zero, or it will run real bad. TIming is set to the flat edge of the timing pointer. You should also hear a difference in the idle with this plugged in vs unplugged. It can be connected with the engine running without breaking anything. If you watch it with a timing light, you'll see the timing marks move with the connector in place.


    The EFI system also has a total of 3 temperature sensors. The coolant temperature sensor is a two wire affair for the ECM. Looking at these exploded diagrams, its front port side of the lower manifold, item 69. There is the temperature guage sensor, single wire thing, front stbd corner of the lower intake, item 25. There is an air temperature sensor two wire thing on the lower manifold behind #5 injector, item 28. Not sure which of these OMC uses for their low power mode, but if you're unplugging the wrong one, it might cause problems. Most likely its going to be the coolant temp sensor though. The two ECM sensors are easy to test with a voltmeter, charts for expected value relative to temperature can be found here:

    http://fordfuelinjection.com/?p=10

    Key on, engine doesn't need to be running to check this but it won't hurt. Values will drift as it warms up though. WOuldn't be a terrible idea to check it engine cold and engine hot to see if you get sane values.

    If they're using a MAP sensor, the vacuum line must be connected. I don't see one in the diagrams anywhere, but its a flat black thing, about the size of a deck of cards with one connector and one vacuum line. This determines engine load. With no vacuum, they typically run horribly rich.

    TPS should also be checked. Its mounted to the top of the throttle body and has 3 wires. If its using typical Ford wiring on the sensor, meter from ground to the green wire. You should see about 1v with the throttle closed, and it should smoothly increase to about 5v WOT, with key on and engine not running. Idle voltage is OK anywhere from .8v - 1.2v but its normally roundabout .9-1.0.

    Fuel pressure at idle with the vac line on the fuel pressure regulator (item 60) is 30-35 psi, no vacuum is 40-45 psi. At WOT, I'd expect to see 30-35 but 29 isn't going to cause any problems.

    Injectors are usually not an issue, and if one is bad you'll usually feel a dead miss, or have a rich running condition that can be tracked to one cylinder. Assuming these are typical Bosch injectors used on all other Fords of that era, they're cheap and easy to get at parts stores. Need to know which color the top of the injector is to size it properly, but you don't have to pay OMC prices for one.

    Is there an engine diagnostic connector on this thing anywhere? If its of the typical Ford type, you can pull codes with a test lamp and a jumper wire. Not sure if the codes may be tweaked per OMC spec, but it surely looks like a regular old Ford EEC IV brain to me, probably with an altered program but there isn't anything special about that computer.They're quite durable, and almost never the source of problems on an EFI Ford.
    1993 Rinker FiestaVee 300
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  23. #23
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    Default Re: 1994 5.0 Cobra EFI stuck at 25% power

    fourwinnsfive , have you been able to find the problem with your engine? please share with the rest of us.
    Thank you

  24. #24

    Default Re: 1994 5.0 Cobra EFI stuck at 25% power

    Thanks for all the detailed help everyone. I have been swamped with work the last few weeks and unable to make it to the boat. I am going to head down there tomorrow and start with the purple and black wire and see if I am lucky enough to have the same problem. I will keep you all posted.

  25. #25
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    Default Re: 1994 5.0 Cobra EFI stuck at 25% power

    Have you been able to repair the problem? please post an update.
    thank you

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