MCM 4.3 MPI RPM restricted until warm

[Wrenchtwista]

Hello all

I have a 2007 Monterey 180fs with MCM 4.3 MPI. I’m having an issue where it will intermittently be sluggish of the hop and not plane. All of a sudden, it will then increase RPM, run great and get up to plane. It’s seems as if it’s being held back and then suddenly smartens up and runs well. It seems to do this more with cooler Engine conditions. If I let it sit for 30 min or so and try to get to plane it goes through the same dance. Not always, but it has done this at warm temps as well. I have a cap/rotor on the way and will change plugs but they really don’t appear bad at all so I’m doubtful that’s the issue. I have read about the water pressure sensors acting up, it going into guardian mode, and am aware there’s also a relocation kit available for the sensor. Apparently they are mounted too close to the coil and are affected by stray electro magnetic pulses or something? Anyway, can anyone suggest a source for said relocation kit or perhaps an alternate issue I should be looking at? I’m quite remote from any dealer to have it check by computer. I’m also not getting any alarms. All gauges reading within normal parameters and when it’s not acting up, it runs very well. Any assistance is most welcome!

 

[alldodge]

Howdy
Check your fuel pressure at the rail, it should be 43 psi
Attach pressure gauge at watch from idle thru WOT

How long have you had the boat?
Has the fuel filter been changed?

 

[tpenfield]

Sounds like you are playing a guessing game, which will get expensive. The best way is to hook up the computer diagnostics and see for real what is going on, but the price of entry is about $500 for the software.

You can check the fuel pressure, as AD said, but there are a number of other things that could be happening. So, you could be in for the long haul, unless you can have the diagnostic software hooked up to the engine.

I had a TPS issue on one of my engines that acted in a similar way to what you are describing. The engine would be idling in gear (600 RPM) and then all of a sudden it was off to the races - 1500 RPM all by itself. Sort of made docking interesting The only way I found the problem was to hook up the computer and watch the TPS output waver from 2% to 15% even though the throttle lever was not being touched. No error codes either, because the TPS was still within its spec'd output range . . . it was becoming intermittent, which was the problem.

Not saying that is the issue with your engine, just that it could be a number of things. Fuel pressure regulator, TPS, WPS, etc . . .

 

[Wrenchtwista]

Howdy
Check your fuel pressure at the rail, it should be 43 psi
Attach pressure gauge at watch from idle thru WOT

How long have you had the boat?
Has the fuel filter been changed?

Thanks for the reply. I bought the boat two seasons ago but put only a few hours on it last year. I have not changed the filter but PO apparently did. I’ll be putting in a new one with the cap/rotor and plugs. If these things don’t resolve I may have to grab the software mentioned. Thanks again.

 

[Wrenchtwista]

Sounds like you are playing a guessing game, which will get expensive. The best way is to hook up the computer diagnostics and see for real what is going on, but the price of entry is about $500 for the software.

You can check the fuel pressure, as AD said, but there are a number of other things that could be happening. So, you could be in for the long haul, unless you can have the diagnostic software hooked up to the engine.

I had a TPS issue on one of my engines that acted in a similar way to what you are describing. The engine would be idling in gear (600 RPM) and then all of a sudden it was off to the races - 1500 RPM all by itself. Sort of made docking interesting The only way I found the problem was to hook up the computer and watch the TPS output waver from 2% to 15% even though the throttle lever was not being touched. No error codes either, because the TPS was still within its spec'd output range . . . it was becoming intermittent, which was the problem.

Not saying that is the issue with your engine, just that it could be a number of things. Fuel pressure regulator, TPS, WPS, etc . . .

Thanks for the reply. I’ll install cap/rotor, plugs, filter and see if that resolves issue. I was able to find a WPS relocation kit so may do that anyway as they are apparently in a bad spot. What software would you recommend? Would the Rinda Techmate Pro unit do what’s needed? Thanks again!

 

[alldodge]

Thanks for the reply. I bought the boat two seasons ago but put only a few hours on it last year. I have not changed the filter but PO apparently did. I’ll be putting in a new one with the cap/rotor and plugs. If these things don’t resolve I may have to grab the software mentioned. Thanks again.

Dump the contents of the filter into a clear container so you can see it there is nothing but clean gas

 

[tpenfield]

Rinda Diacom is the full software ($579 ish). The techmate pro is not that much less ($499 ish), yet I'm not sure it does all (and shows all) that the software does. Maybe talk to Rinda about the differences.

I like the software because you can record the data while the boat is acting up and then play it back later at home while you are having a beer, figuring out which sensor to buy/replace. :thumb:

 

[QBhoy]

See what the cap does for you and go from there. Half the time I read similar issues like this from an mpi...that’s the issue...especially this time of year. Good to rule it out if nothing else.

 

[achris]

Rinda Diacom is the full software ($579 ish). The techmate pro is not that much less ($499 ish), yet I'm not sure it does all (and shows all) that the software does. Maybe talk to Rinda about the differences.

I like the software because you can record the data while the boat is acting up and then play it back later at home while you are having a beer, figuring out which sensor to buy/replace. :thumb:

And you can send me the files, and I can have a beer by them as well.

But yes, the Diacom, while a couple of hundred dollars more, is worth every cent. If there were any down side to the software, it's that you need a laptop to run it. For me that was no issue, I already own several.

Chris.........

 

[Wrenchtwista]

And you can send me the files, and I can have a beer by them as well.

But yes, the Diacom, while a couple of hundred dollars more, is worth every cent. If there were any down side to the software, it's that you need a laptop to run it. For me that was no issue, I already own several.

Chris.........

Thanks. I have An old laptop running XP so no sure if it will be compatible. I’ll look into it. Thanks again.

 

[Wrenchtwista]

Now, I understand that the rotor terminal doesn’t touch the cap terminals but this gap seems a bit excessive. Is this a normal gap?

 

[alldodge]

No first hand knowledge, but looking at other pics online it appears to be the same

 

[Wrenchtwista]

I was checking on which ECM I have in order to buy the Diacom software To find out what’s going on with this engine and thought I’d give everything a once over again. Well, turns out the connector for the #1 injector was not fully in place. It would make contact at times and run great but mostly not. After fully seating the connector, it runs great! That was a close call on almost dropping $600! Thanks again to all for your suggestions.

 

[tpenfield]

In the famous words of the I.T. Helpdesk . . . "is it plugged in? it's a common problem you know . . ."