OMC Cobra 5.0L EFI Spudder

[Danno5.0]

Hi all,

I've done some searching on the subject, and found a few things to try, but most of the posts on the subject didn't have a solution posted. One guy replaced a MAP sensor that helped his similar problem.

So here goes w/ a few more questions:

I have a 94' Fourwinns Horizon 190 w/ a 93 OMC Cobra 5.0L EFI.
It runs fine at idle and at moderate speeds ~ 25 mph.
It spudders if I try a WOT, or if I try to exceed 25.
Spuddering = A short drop out that cycles steady until I back off the throttle.
If I increase the throttle while it's happening the cycle is more frequent or faster.

It seems like its a fuel delivery problem because it acts like a momentary fuel drop out.

Here's what I've done so far:
Cap & Rotor replacement.
New Plugs
New Fuel Filter
Dry Gas
Fuel Injector Cleaner
Octane Boost
Drain Tank / Add new Fuel
Clear Gas Tank Air Vent.

One thing I did differently last fall when winterizing was fogging the engine throught the Air Intake at the throttle body. ( I read in a thread that this could possibly damage an injector or two?? )

In the past I've used an outboard tank w/ the fogging mixture, or sprayed directly into the cylinders by removing the spark plugs (what a pain that is).

Things I plan to try:
Using an outboard gas tank to rule in / out my tank.
Replacing the MAP sensor.

Thanks, looking forward to some replies.....

Danno

 

[Otiville]

Re: OMC Cobra 5.0L EFI Spudder

I have been dealing with the same problem for awhile now also.
I have a 94 Four Winns Horizon 190 with a 5.0L MEFI engine.
Your list of things to try I have also done to no avail. I am now going to change the MAP sensor. I found one on EBAY and saved a lot of money. I will report back when I get it. One interesting observation I just discovered ---
If I start the engine cold and immediately accelerate to WOT, it works fine until it warms up (which isn't long) then it returns to the sputtering, in this case it is 3400 RPM.
I have not hooked it up to a computer because non of the local mechanics have one, so until I get to the real expensive parts, I will avoid trailering it 75 miles for a repair until I absolutely have too.

 

[frustratedboater]

Re: OMC Cobra 5.0L EFI Spudder

Have you tried disassembling the carb throttle body and check for water & crap? I had an 86 four winns (almost simular setup) that had water buildup in the tank, which filled the fuel/water seperator, and then settled in the carb main bowl (had bits of sand and junk as well) which led to simular issues you are explaining.

I picked up a water/fuel siphon tube from harbor freight for $8-10 (like an outboard fuel bulb with two clear hoses on either end) and tilted the trailer real high and let the water settle in the back of the tank for about 5 minutes. I pulled out the fuel sender, then siphoned out about 1 quart and a half of water and junk from the bottom of the tank (tank should be no more than a third full-depending on where the sender is located--you don't want fuel spilling everywhere!!) IF YOU DO THIS BE SURE TO GROUND YOURSELF AND BE SURE THE BATTERY IS DISCONNECTED AND ALL POWER TOOLS ARE NOT AROUND SO NOTHING WILL SPARK VAPORS!!!! IT WILL RUIN YOUR SUMMER!! .

I then dumped out the seperator upside down for a while, then refilled the filter with gas about a half an inch from the top and replaced it (I wanted to save a buck) then did the carb procedure last and found more unwanted stuff. After that the boat never ran better. I sold it while it was running great.

It's worth considering...

~FB~

 

[frustratedboater]

Re: OMC Cobra 5.0L EFI Spudder

Actually, my reply would not apply. I missed the fuel injector/drain tank part...

~FB~

 

[180shabah]

Re: OMC Cobra 5.0L EFI Spudder

Things I plan to try:
Using an outboard gas tank to rule in / out my tank.
Replacing the MAP sensor.

You fogged it through the intake - MAP is most likely dead now.

Spraying fogging oil through the intake is NOT proper technique for EFI because you can't keep it from getting inthe MAP sensor.

 

[Danno5.0]

Re: OMC Cobra 5.0L EFI Spudder

You fogged it through the intake - MAP is most likely dead now.

Spraying fogging oil through the intake is NOT proper technique for EFI because you can't keep it from getting inthe MAP sensor.

Thanks - I'm gonna try to locate one ASAP and give that a try.

 

[Danno5.0]

Re: OMC Cobra 5.0L EFI Spudder

I have been dealing with the same problem for awhile now also.
I have a 94 Four Winns Horizon 190 with a 5.0L MEFI engine.
Your list of things to try I have also done to no avail. I am now going to change the MAP sensor. I found one on EBAY and saved a lot of money. I will report back when I get it. One interesting observation I just discovered ---
If I start the engine cold and immediately accelerate to WOT, it works fine until it warms up (which isn't long) then it returns to the sputtering, in this case it is 3400 RPM.
I have not hooked it up to a computer because non of the local mechanics have one, so until I get to the real expensive parts, I will avoid trailering it 75 miles for a repair until I absolutely have too.

Where did you find the part number for that?
I was going to call my local dealer to see if they can help.

Certainly let me know how it works out for you....

Thanks !

 

[Danno5.0]

Re: OMC Cobra 5.0L EFI Spudder

Actually, my reply would not apply. I missed the fuel injector/drain tank part...

~FB~

Thanks for trying though !!

 

[Danno5.0]

Re: OMC Cobra 5.0L EFI Spudder

Okay, so I called my local boat dealer to find out that the MAP sensor is obsoleted for my 93 OMC.

So, I jumped online to see if I could find a replacement part based on the model year Ford MEFI 5.0L, but can't narrow down which one is right for my application. My local boat dealer suggested either a Crown Vic or Mustang application, and to call the NAPA store.

So, I call them and they need to know the part number cause there are a few different ones.

I went down to the boat to try to locate the part and get the number.....
But, I can't find the little sucker.

Anyone have a clue where it might be located??

I called the local Ford dealer and they said it could be remotely mounted, but there should be a vaccum hose attached to it. (makes sense cause the parts I see on line have a 3 wire connector and a vaccum nipple)

I still can't find it, and now I'm doubting that it even exists on this boat.
You'd think that it would be mounted to the air intake manifold or near the throttle body??????

Anyone have any links to diagrams or pics where I can spot the thing?

Thanks !!!

Danno5.0

 

[Danno5.0]

Re: OMC Cobra 5.0L EFI Spudder

I got a hold of a 1986-93 shop manual. The trouble shooting area doesn't have much for the EFI version, except for suggesting that the EFI system is complicated and they reccomend taking it to a dealer.....

But there is a wiring diagram in the back of the manual of the 5.0 and 5.8 L EFI. Lo and behold there is a MAP sensor shown in the diagram.:redface:

Now just have to be able to loacate it on the engine.

Thx - Dan

 

[Danno5.0]

Re: OMC Cobra 5.0L EFI Spudder

Wu Who - I think I found it.....(in the maunal)
The section on engine removal shows the location.
It's actually in plain sight, I just didn't know thats what the device was....

Whew - I was begining to think I had to send it to the shop.....
Hopfully I can find a local replacement ; )

THX

 

[Danno5.0]

Re: OMC Cobra 5.0L EFI Spudder

Sure enough, that was the part and location

For those in the need here's the part number: E7DF-9F479-A2A

Now hopfully this does the trick !!

 

[SeaRaytony]

Re: OMC Cobra 5.0L EFI Spudder

im having a similiar problem with my 5.7 omc! Did replacing the MAP work to correct your problem?

 

[Danno5.0]

Re: OMC Cobra 5.0L EFI Spudder

Haven't tried it yet.
I just found them on ebay at a much better price than locally.
Murrays Auto = $80.00
NAPA = $125.00
ebay = anywhere from $24.95 to $75.00
Search on the # AS1 as a repacement part.

 

[Otiville]

Re: OMC Cobra 5.0L EFI Spudder

Check web sites like www.volvopentastore.com They have exploded views for various combinations that will lead you to the part number, mine is 3854160 (1994 5.o L FI)
My year is the year they went from OMC to Volvo Penta, but the parts are interchangable

I haven't received the sensor yet, but I hope to have it on & tested on Sat 6/13 I'll post after I test it.

 

[Ocean 22]

Re: OMC Cobra 5.0L EFI Spudder

I have the same engine in my boat OMC\volvo 5.0 FI 1994. I have similar issues. My engine will run great at idle and rev up fine when out of gear, but once you put the boat in gear. It will not get past 2800 to 2900 RPM. At that speed it will get the boat on plane, barely 10 MPH. I have tried replacing the Map sensor, the Engine coolant temp sensor, the Idle air control valve, and the Throtle position sensor, AND IT still RUNS LIKE S--T. I am so frustrated. Has anyone out there experienced the same Issues? PLEEEASE HELP

 

[Danno5.0]

Re: OMC Cobra 5.0L EFI Spudder

Thanks for the info.....
I just snagged one off of ebay motors....
Hopefully this works for us..

Dan

 

[Danno5.0]

Re: OMC Cobra 5.0L EFI Spudder

I have the same engine in my boat OMC\volvo 5.0 FI 1994. I have similar issues. My engine will run great at idle and rev up fine when out of gear, but once you put the boat in gear. It will not get past 2800 to 2900 RPM. At that speed it will get the boat on plane, barely 10 MPH. I have tried replacing the Map sensor, the Engine coolant temp sensor, the Idle air control valve, and the Throtle position sensor, AND IT still RUNS LIKE S--T. I am so frustrated. Has anyone out there experienced the same Issues? PLEEEASE HELP

Oh, the MAP didn't help eh?
Well for $34.00, I figured it will be worth a try.
Curious to see if Otiville has any luck.....

Have you tried the other stuff like a tune up & fuel filter?

D

 

[Ocean 22]

Re: OMC Cobra 5.0L EFI Spudder

THe engine is completely rebuilt. all new components internally, new fuel pumps, plugs, wires, filters. The engine has excellent compression. It has already been compression tested. After 3 months, several thousand $$$. I am Really FRUSTRATED. IT seems that no matter what i do to this engine it will not rev up under load. I have asked if anyone knows how to check the S.L.O.W circuit which reduces engine RPM if the boat overheats or Looses Oil pressure. When the Engine Blew up due to a cracked manifold the engine computer activated the SLOW circuit. Perhaps it is stuck in that Mode. THe volvo manual says that once the problem is corrected the computer should resume normal operation. I JUST cannot get this engine to run correctly. The map sensor did not resolve my issue, however perhaps it will resolve yours You never know with these engine.

 

[Ocean 22]

Re: OMC Cobra 5.0L EFI Spudder

BTW where did you find it for $34 bucks?