Volvo Pentre 4.3 G. Running problems

[Toddy2]

I have a Volvo Pinter 4.3 Gi.
I have some running issues I hope somebody can help me.
Today I took the boat out on the lake and ran fine for half an hour. It then started to die as if it was running out of fuel. I pulled the throttle back and the engine ran fine. I then applied the throttle slowly and as I got up in RPM the engine started to bog down. I pulled the throttle back again and the engine ran fine. The engine does not seem to want to run above 2500. It will run fine at lower RPMs and perfectly at idle.
Does anybody have some suggestions or tests for the fuel injection system.
Many thanks

 

[ericga]

That usually means your engine is running in protection mode (overheating, low oil pressure, engine knock etc..). Start here:

http://forums.iboats.com/forum/engi...ves/302506-list-of-possible-causes-of-low-wot

 

[Toddy2]

Thank you for your suggestions. I will try and find a Volvo Penta diagnostic key but I think I will have great trouble with this in New Zealand.
Things get interesting this morning with nothing to lose I removed the TBI. Just in case of a fuel blockage. Gave all parts a good clean there was nothing obvious and no contamination from old fuel. I reassembled the TBI and test ran the engine.
The engine is running very rich. I am starting to think I may have a map sensor issue.
What do you think.
My biggest issue here in New Zealand Volvo is nearly non-existent and I have no dealer principal master tech to turn to specially with petrol engines. They only want to know about diesel engines. I have also found I can?t get TBI rebuild kit?s here in New Zealand for my 4.3 GI 2000 model.
Look forward to hearing your suggestions
many thanks

​

 

[Tail_Gunner]

I am going to be of little help here other than to tell you its time to walk away from the fuel injection (tbi) Remember its 80's tech and that's not a bad thing just extremely expensive and very hard to find experience and parts
Putting a carb on would be by far less costly ...expensive and probably better performance. How do I know I have the same engine and one more hickup and it's gone.

 

[ericga]

Start with the obvious. Re-seat sensor connections (knock, temp, oil pressure etc...) cap, rotor, map sensor hose leak, engine grounds etc... There should be a schrader valve on top of the high pressure pump to connect a fuel pressure gauge. You should get 29+- 1 PSI at all time while the engine is running. You need to find out if you are dealing with a fuel or an electronic problem first.

 

[Toddy2]

Thank you for your suggestions.
I have fixed the running rich problems. Found a injector with a split O-ring.
Still have top end running issues and I think it?s coming down to a high-pressure fuel pump.
Will let you all know when I have had a chance to connect a pressure gauge.
Just too many outboards to fix at work always seem to leave my own boat to the last.
Thank you for all the advice certainly getting to the end of the problem.

 

[Toddy2]

Hi guys thought it was time to give you an update and let you know where I am at.
Finally check all fuel pressures everything was within specifications.
I grabbed another mechanic from work to have a look at the engine while we were running.
Not easy looking at the engine from the steering wheel.
We discovered one injector stopped firing when we reached 2000 rpm under load.
Removed the wiring harnesses and swap them around the problem followed the wiring harness. Have track things back and now find it is the ECM at fault.
Have now come to my biggest regret I will be removing the TBI and installing a holly carburettor. It just doesn?t seem right going backwards to a carburettor but it will be the only way forward when parts are hard to obtain in New Zealand.
Hope this final postal help somebody else in the future if they discover the same problem.
These engines are now 14 to 15 years old and will start giving electronic component problems. Going to carburettor will give you more reliability and keep your engine going just that little bit longer.
Thank you for everybody who has given advice and read this post appreciate your assistance.
t

 

[ericga]

one injector stop @ 2000 rpm means engine is running in protection mode. You need a mefi marine scanner to find out.

 

[ericga]

RPM Reduction Mode
The ECM recognizes a change of state in a discrete switch
input that identifies an abnormal condition. During these
abnormal conditions, RPM reduction mode allows normal
fuel injection up to OEM specification (approximately 2000
RPM). Above the OEM specified RPM limit, fuel delivery is
limited to half the fuel injectors until the engine drops below
1200 RPM. Then normal engine operation is restored until
the RPM limit is exceeded again. This feature allows
maneuverability of the boat while removing the possibility of
high engine speed operation until the problem is corrected.

 

[Toddy2]

Thank you for your post.
Unfortunately scan tools are not available for this old engine I have enquired with several dealerships. This is the problem when you have an engine that is not common in your country.
Today I ditched the TBI injection unit. I have bolted on a double barrel holly carburettor.
The changeover was much easier than I thought. Just unplug the senses from the TBI and then remove the high-pressure fuel pump. I was lucky to pick up a carburettor that was from an earlier Volvo Penta. This meant everything dropped in place the throttle linkages slid straight on. My only hassle was making up a new fuel line to go directly from the lift pump to the carburettor.
I test ran the boat today on the lake for half an hour and everything is running fine. I would even go to the point of saying smoother than it was with the TBI. Idle is certainly a lot smoother. I have noticed a small drop of about 2mph in top speed according to the GPS.
I will do some more test running over the weekend from where I am sitting at the moment it?s the best move getting rid of the troublesome electronic fuel injection.