Volvo Penta 5.0fi (ford)will Not Rev Past 2800 Rpm At Wot

[Ocean 22]

I am at my wits end with this engine. After going thru months of chasing down the correct parts to finish my engine rebuild i cannot get this engine to run correctly. I rebuilt the engine with all new internal components. In addition i replaced the distributor with a new one, new coil, new fuel pumps, new plugs , cap rotor, map sensor, idle speed control valve, throtle position sensor, ECT sensor, i replaced the injectors with rebuilt ones. I have gone thru the list that Don S posted concerning causes that would affect an engine to not rev up during WOT, and all 15 items on the list are in order. The engine idles great, and will rev up to red line out of gear, however when you put in gear and you push WOT it will not rev past 2800-2900 rpm. I have checked the entire fuel system for pressure, and performed leakdown test. tested fuel pressure regulator. all are within specs. I even tested the fuel pressure with boat in the water at WOT, and it is rigth where it needs to be 39PSI. I have also checked the base timing, and the computed timing. the computer advances the timing correctly. I have also checked the engine harness circuits to all the sensors and everything is fine. I know that these engines came with A S.L.O.W circuit that will kick in in the event of low oil pressure or engine water overheat, however there are no such issues with this engine. Could it be stuck in this mode from the time the engine Blew up on the boat. One more thing, i did a compression test on the engine, and all cylinders have good compression. Can anyone please help me out? Has anyone out there owned a boat with this engine or The OMC version which is identical.

 

[Bt Doctur]

Re: Volvo Penta 5.0fi (ford)will Not Rev Past 2800 Rpm At Wot

what firing order are you using?

 

[Ocean 22]

Re: Volvo Penta 5.0fi (ford)will Not Rev Past 2800 Rpm At Wot

The firing order for this engine i like a Ford 351 1 3 7 2 6 5 4 8. It is a standard rotation engine. What do you think is causing this engine problem?

 

[Bt Doctur]

Re: Volvo Penta 5.0fi (ford)will Not Rev Past 2800 Rpm At Wot

Any chance the replaced injectors have a smaller flow rate?

 

[cr2k]

Re: Volvo Penta 5.0fi (ford)will Not Rev Past 2800 Rpm At Wot

Check the shift interrupter module.

 

[Ocean 22]

Re: Volvo Penta 5.0fi (ford)will Not Rev Past 2800 Rpm At Wot

I will check the injectors thank you. Where is the shift interupter module?

 

[bruceb58]

Re: Volvo Penta 5.0fi (ford)will Not Rev Past 2800 Rpm At Wot

Check the shift interrupter module.

There is no shift interrupt module on a Volvo.

Check and double check and triple check the firing order...don't ask me why

Note that Ford is different than Chevy for how the cylinders are numbered.

 

[mycirus]

Re: Volvo Penta 5.0fi (ford)will Not Rev Past 2800 Rpm At Wot

That drawing above says 351, is it the same? My Larson was doing the same thing but it got a little better. I have the 5.0 FL and I could not get it past 3200 RPM until yesterday. I put fresh plugs, cap and rotor in it, changed the filter, ran through a full tank and filled again, used sea foam to clean it out and I am still having issues which I think are electrical related. Someone mentioned the shift interupter module. I would like more info on that please. Thats what I think might be happening to mine. Every now and then I stall out and get a backfire. Also happens on de accel when coming down.

 

[Ocean 22]

Re: Volvo Penta 5.0fi (ford)will Not Rev Past 2800 Rpm At Wot

UPDATE: I CHECKED OUT THE INJECTORS ON THE ENGINE AGAINST THE ORIGINALS THAT I REMOVED AND THEY ARE THE SAME COLOR ON THE TOP PLASTIC- YELLOW, HOWEVER THEY ARE NOT THE SAME FORD PART NUMBER DOES ANYONE KNOW HOW MANY PSI THE ORIGINAL VOLVO INJECTORS ARE? I HAVE ALSO TRIPLE CHECKED THE WIRES AND FIRING ORDER AND IT IS CORRECT THANKS BRUCEB. PLEASE PEOPLE ANY HELP WILL ALLOW ME TO FINALLY GET OUT ON THE WATER. I need to get out on that water bad. mycirus volvo penta does not have a shifter interrupt on a volvo. the 5.0 and 5.8 (351) have the same firing order. I would check your DECELERATION VALVE. it is located somewhere on your manifold near the carb. it has two vacum hoses attached to it -one large, and one small. to test valve:

1. warm up the engine
2.with engine running at idle disconect the small hose from the manifold but leave connected to valve.
3.reconnect hose and listen for air flow into the valve. there should also be a noticeable RPM DROP when the hose is reconnected to the manifold.
4. if the air flow does not continue for at least one second or the engine RPM DOES NOT DROP noticeable. you need to check the hoses for leaks or restrictions (KINKS).
5. If no restrictions or leaks are found REPlACE THE VALVE.

I HOPE YOU ARE ABLE TO GET IT RUNNING CORRECTLY.

 

[mycirus]

Re: Volvo Penta 5.0fi (ford)will Not Rev Past 2800 Rpm At Wot

Awesome thanks. I will check that out. Although I was leaning more toward an electrical issue to do the backfire and loss of power. Its like if I pull my safety switch and put it back on quick.

 

[fast50]

Re: Volvo Penta 5.0fi (ford)will Not Rev Past 2800 Rpm At Wot

have you put a vacuum gauge on at load and check the response compared to throttle angle the gauge should snap back as soon as you close throttle

 

[Ocean 22]

Re: Volvo Penta 5.0fi (ford)will Not Rev Past 2800 Rpm At Wot

The engine i have is a 1994 Volvo penta 5.0 FI . Have checked the firing order in the volvo mamual and it is correct for this engine. I did try to connect a Actron scan tool that i have ( the large orange one that you can get at pepboys or auto zone), however it is meant for a car, and called the company that makes the tool. they told me to choose a ford truck with the same engine , but i do get the scanner to work, but it will only give me a pass code 11. THe volvo penta manual is very limited on information on this topic. all they tell you to do is perform a lot of pinpoint test. the test consist of testing the actuators and sensors. i have not found any faults. i have even checked engine harness but have not found any problems. The engine runs great except when you put a load on it. Like when you want to get the boat up on plane at WOT. thank you for your suggestions. Do you have any other areas that i should check?

 

[Ocean 22]

Re: Volvo Penta 5.0fi (ford)will not reach full throtle

Re: Volvo Penta 5.0fi (ford)will not reach full throtle

Any Fuel INjection Experts out there please help. PLEEEEASE!

 

[Don S]

Re: Volvo Penta 5.0fi (ford)will not reach full throtle

Re: Volvo Penta 5.0fi (ford)will not reach full throtle

What is your engines FULL model number, including the letters after the Fi.
You mention your Volvo manual. Is it the Volvo OEM service manual, or a Seloc or Clymers aftermarket manual?

 

[Ocean 22]

Re: Volvo Penta 5.0fi (ford)will Not Rev Past 2800 Rpm At Wot

I looked at the engine plate and it Reads OMC Cobra Model # 5 0 FAPHUB. This engine is a 1994 which i believe is the year that OMC & Volvo penta were going thru some kind of partnership. My engine came the SX drive not an OMC .Cobra Drive, although on the sterndive it says SX COBRA. I have the original volvo penta manual with all the different books that come as a set as well as the Seloc Manual, however the volvo manual does not have a way to check this so called SLOW safety feature that the boat comes with. It does have wiring diagrams for the SLOW circuit but no procedure for cheking the sensors or any other part of the system. At this point i am trying to figure out what to check for. I have already checked all the other things that everyone posted with the exception of changing the injectors (very Pricey). I appreciate any advice you can give.

 

[Sunny2007]

Re: Volvo Penta 5.0fi (ford)will Not Rev Past 2800 Rpm At Wot

How about a clogged check valve in the pickup tube on the fuel tank ?
Would a fuel restriction reduce pressure ?

I have a boat that wouldn't WOT past 25-2800 and the previous owner told me it had a governor on it.After checking around,i found the check-valve was gummed up with varnish.

Just an idea

 

[Don S]

Re: Volvo Penta 5.0fi (ford)will Not Rev Past 2800 Rpm At Wot

What you need to do is hook up a diagnostic computer to the engine and see what it's doing. It will tell you if the slow system is activated and why it's activated. You have to have all the tools and knowhow to diagnose a problem. Otherwise you are stuck with changing parts till you happen upon the proper one.

PS: You have an HU model, which is the 95 version.

 

[Jabaen]

Re: Volvo Penta 5.0fi (ford)will Not Rev Past 2800 Rpm At Wot

Ocean22, I see that this thread is a couple of months old but, were you able to solve the problem? I had the same problem with my Volvo Penta 5.8fi. If the engine cuts out at 2800 rpm, it is the Slow Circuit being activated. The ECM will stop firing injectors until the rpm drops below. The ECM does not remember this mode. Once the sensors return to normal, it switches this mode off. It only works for a low oil pressure or over heated water temp. and they are contolled by seperate sensors. The engine actually has two oil pressure sensors and two temperature sensors. The sensors for the SLOW circuit connect to ground if their threshold is met. All SLOW circuit sensors are connected to the same wire that goes to the ECM. If any sensor is grounded (or if the wire has a break and is grounded) will cause the ECM to enter the SLOW mode. The ways to diagnose it are to use a code scanner and plug it into the diag port for the ECM. It will give a code indicating that the computer is in SLOW mode. (I can't remember which code it was, it was in the Volvo Penta service manual). You can also test the wire that goes to the computer to see if it is grounded. (At the back of the engine where the wires come out of the harness for for trim/tilt sensor, there are two loose wires. One is ground and the other (I believe it is brown) connects to the SLOW circuit. If you jumper these two wires, you'll put the computer in SLOW mode. You can test the brown one by itself to see if it is grounded.) The next step would be to disconnect the oil and temp sensors seperately to see which one is not functioning and then replace it. For me, it was the oil sensor. Even though the oil guage was showing proper pressure through its sensor, the oil sensor for the SLOW circuit was faulty. Sorry for the long reply, hope this helps you or someone else.

 

[Ocean 22]

Re: Volvo Penta 5.0fi (ford)will Not Rev Past 2800 Rpm At Wot

I have not been able to quite get a fix on the problem. I ran the boat a couple of weeks ago, and it did rev up to full rpm at WOT. However it ran fine for most of the day and the it would not rev up past 2800 rpm when in gear. I did try to disconnect both the SLOW sensors while i was on the water, and it did not seem to make a difference. I am going to try to check the wiring for a short to ground. I really apreciate your help. I will post an update after this weekend.

Thank you

 

[hoehopper74]

I see this thread is old but did you ever fix this problem thank you