Boat won't start unless 3/4 throttle. IAC valve issue?

[whitesharkseeker]

So my engine (1996 VP 5.7 Gi) RPM's were erratic, jumping up and down at idle. Cleaned the IAC and problem solved. Now, after a month of boating, boat won't start, just cranks, catches, and dies. I have to use clear flood mode by opening the throttle 75% to get engine started. Boat runs fine but every time I turn it off, regardless of warm/cold start I have to use clear flood mode. Any suggestions? TPS, IAC, crank sensor?

Thank you, Eric Mailander

 

[alldodge]

Your advancing the throttle to get it started, and once started can it be returned to idle and it continues to idle OK?

If it does its not the IAC

Has the injectors ever been cleaned and flow tested?

As in most cases with EFI it will need to be scanned for codes

 

[whitesharkseeker]

Thank you. I have the TBI, and injectors appear to be spraying well, in the v-pattern. EFI cannot be scanned do to wire issues, or so a mechanic told me. Yes, the engine idles fine after I clear the flood if I bring throttle back slowly. Sometimes takes 2-3 attempts but always runs find after cleared.

-Eric

 

[alldodge]

Were just guessing without a scan. Sure wonder what the wiring issues are. there are only 4 wires and they are all on the DLC connector

 

[Lubak572]

What is the clear flood mode?

 

[QBhoy]

Does it give a kick when you release the key when it’s not starting ? If it does...it’s the battery.

 

[whitesharkseeker]

Not the battery. Both brand new and crank strong.

 

[whitesharkseeker]

A flooded engine can be cleared by opening the throttle 75% of its travel. Once this is done the ECM shuts down the fuel injectors and no fuel is delivered to the cylinders.

 

[QBhoy]

Not the battery. Both brand new and crank strong.

Ok. Maybe not the problem but just be aware that these gxi and mpi will both crank strong but if anything less than a great battery, will not start. The cranking takes the power away from the ecu and ignition enough not to fire it until you let go of the key. Very very common.