1996 Fourwinns 5.0 efi Ford

[mfour4]

Am working on a boat that hasn't run in over 10 years. After installing a new gas filter and new water pump all runs well with one exception ......in idle in gear ( 1000 rpm ) the motor will stall. Starts up right away but will do the same thing 5 or 10 mins later. Runs very well high speed and I can keep it from stalling if I run it about 1500 rpm though it does try to stall by sort of hiccuping but continues to run normally after. I feel its a sensor possibly but am not sure where to look.
Any advice would be appreciated.
Thx in advance

 

[Jammer864]

Re: 1996 Fourwinns 5.0 efi Ford

Drivability problems are the hardest to diagnose. I have the 5.8 EFI in my boat and its been flawless but I have an interest in the Ford EFI from my mechanic days years ago. Heck, I even have a breakout box for the thing thats never been used. I guess I have been lucky in the 11 years I have had the boat.

Dont just assume its a sensor. This poor engine hasnt run in 10 years. Are the vacuum lines to the MAP sensor and fuel pressure regulator hard, cracked, and therefore leaking? Is it leaning out or too much fuel that is killing it? One starting point would be fuel pressure. I believe this engine needs 31 plus or minus 3 PSI minimum at idle. Check the vacuum lines first and then the fuel pressure. One area to focus on is the Idle Speed Control (ISC). This is supposed to regulate idle speed using various inputs such as Engine Coolant Temp, Air Charge Temp, Throttle Position, Manifold Absolute Pressure, and Profile Ignition Pickup. If you are going to diagnose this idle problem, you would do well to find a manual and study what controls the idle system. Some of these sensors will record a Service Code in memory and can be retrieved.

So start off with some basics. Assuming fresh and clean fuel and no air intake restrictions check the vacuum line condition and fuel pressure. If those are good, move on to the ISC system and its various inputs. Use the factory service manual to verify the specs on the inputs. I have the 1994 Volvo-Penta EFI Workshop Manual. You may be able to find it online for free.

Let us know what you find out.

 

[mfour4]

Re: 1996 Fourwinns 5.0 efi Ford

Thankyou very much for your input. I think as things stand now I will be looking for a manual as I was already leaning that way. All vacumm lines are good as the boat was well stored and other than this stalling it runs very well. I am out in Nevada and run it on Lake Mead and the Colorado River.....mainly fishing.....
thx again