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Slow mode cause 2500 rpm rev limiter

J

jackspivey2

Contributing Member
"1993 OMC 5.8L EFI ran fine mo

"1993 OMC 5.8L EFI ran fine most of the day, then after stopping at the dock for a few minutes, the motor would not go past 2500 rpms. Oil pressure was 40 sweeping up to 80 as the motor approached 2500. Water temp was 150. Could run up to 2400 no problem, after 2400 motor just bounced off the rev limiter at 2500. Any ideas? Happened in nuetral and in gear."
 
Jack...with that EEC module in

Jack...with that EEC module in there and all those sensors I'm afraid your going to have to find a shop that can plug into it and tell you what's wrong. No point in guessing.
 
"That's what I was afraid

"That's what I was afraid of. I was hoping that there was a way to scan the codes without a scanner like the old fords with a multimeter and a couple of wires. Guess I won't be that lucky. Gonna try disconnecting a couple switches and see if one of the simple ones is causing it. Just noticed a fuel pressure switch after the water seperator, thinking maybe the seperator is clogged due to old gas and stuff, or the oil pressure switch and finally the temp switch as those are seperate from the sending unit for the gages. I will post back to let anyone interested know what it ends up being. Just never seen an i/o with a safe mode before...new to me!

Jack"
 
Good News! For everyones futu

Good News! For everyones future reference these EFI systems use an oil pressure sending unit for the gage and a pressure switch for the computer. Luckily it was just the pressure switch. Unplugged it and the motor revs fine now. Local NAPA store was able to match up the switch for $11.00 and back out to the water she goes.

Jack
 
"I just saw this post because

"I just saw this post because I have a 1993 OMC 5.8L EFI engine that was doing the exact same thing. As soon as I get to 2500 it would cut out.

I will look at the oil pressure switch. Thanks.

I wanted to let you know that you can check the engine codes with some wires and a multimeter.

Please see the following link:

http://www.fordfuelinjection.com/?p=13

I suggest you use a lightbulb. my digital Multimeter did not work well. I was able to read my codes without buing a ODB I reader.

Good luck."
 
"I'm new to this boating f

"I'm new to this boating forum. I have a '95 24' Chris Craft with a '94 OMC 5.8L 351 Spitfire engine. I have had the same problem with the rev limiter preventing the boat from reving above 2600 rpm and being able to get up on plane. I've had the boat with the service tech of our local marina for weeks and they haven't been able to figure out how to test the EEC functions. So the above information to check out the oil pressure sending unit is invaluable. I hope that works, thanks!
Chris J-Y"
 
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