2003 5.0 MPI Hard to Start When Cold

[adboyd06]

Second season with this boat and we launched on Thursday after the boat spent the winter in inside heated storage. Starboard engine was very hard to start, port engine fired as expected. Starboard engine would run for a second or two and then stop, restart, run for a few seconds and then stop. Eventually was able to start the boat after a few tries by moving the throttle to wide open and quickly pulling it back. Let it run at around 1,000 RPM for a minute and then it would idle fine. Once warm, the engine would start as expected. Water temp was good, oil pressure was good and performance of both engines were great (once warm) ran for about an hour to get across the lake to our slip, topped off both tanks 90 rec fuel. Stopped both engines and both restarted without issue.

Back to the boat the next day, same issue - port started quickly, starboard would not start without full throttle.

The engines need some maintenance and a tuneup but I'm just wondering what the potential problem could be since once engine is fine and the other isn't. Thinking the following will need to be replaced on both engines: spark plugs, wires, cap, rotor, and the IAC valve. Will also do oil changes, filters and fuel/water separator filter.

Anything I'm missing or should check?

Vessel View Mobile returns the same faults on both engines: 130-Legacy engine or drive trim position, 104-Legacy Sea water temperature, 119-Legacy Steering position, 94-Legacy Pitot pressure, 75-Legacy Level sensor tank but I assume those faults are because there are no sensors for those items.

Thank you.

 

[alldodge]

Vessel View Mobile returns the same faults on both engines: 130-Legacy engine or drive trim position, 104-Legacy Sea water temperature, 119-Legacy Steering position, 94-Legacy Pitot pressure, 75-Legacy Level sensor tank but I assume those faults are because there are no sensors for those items.

Agree

The engines need some maintenance and a tuneup but I'm just wondering what the potential problem could be since once engine is fine and the other isn't. Thinking the following will need to be replaced on both engines: spark plugs, wires, cap, rotor, and the IAC valve. Will also do oil changes, filters and fuel/water separator filter.

May need all that stuff depending on how old, and always good to replace cap and keep old as spare. The caps can last a long time or very short time. The issue is there can be no signs and they just give up the ghost or start causing problems.

Don't see your current problem being any of the tune up items currently

The IAC may be the issue because it needs cleaning. I would remove and clean it with non-caustic cleaner, then give another try.

 

[Jersey Guy]

I had a similar problem with my MC 7.4 MPI L29 Gen VI will not idle properly while cold.

I was looking for the IAC and I am not sure I found it. I have pictures but I cannot upload them to this thread.

If anyone can show me where the IAC is on my engine I would appreciate it. I don't want to start taking things apart and make things worse.

Thank you in advance...

 

[adboyd06]

Thanks for the input. Could it be a faulty sensor? Or would that be picked up as a fault by Vessel View?

 

[alldodge]

If the TPS or IAC had a fault then it should display on vessel view
A scanner would tell you wants going on. Would need to look at the IAC counts

 

[adboyd06]

Well I found my problem. Here is what the cap looks like. I scrapped the corrosion off of the terminals and it started right up and stay running. I have all of my tune up parts ordered and will tackle that this weekend..

 

[QBhoy]

My goodness. Another diz cap issue. Surely we need to put a headline sticky on the forum about this now ? It must be the single most common spring start up issue on the mpi ?

 

[QBhoy]

JrPickle achris

 

[alldodge]

My goodness. Another diz cap issue. Surely we need to put a headline sticky on the forum about this now ? It must be the single most common spring start up issue on the mpi ?

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