2003 5.7 mag mpi idle issue

[Captn_carroll]

Greetings all!

I recently acquired an oldy but a goody with a 1966 19' Owens Xl with the following:

2003 mercruiser 5.7 mag mpi alpha (no serial#)
- tag has been removed by starter and top cowl markings have since faded
-is there another secret location for the sn?
-275.7 hrs

Rebuilt born warner 71c direct drive transmission

13x15 3 blade lh prop

I'm rebuilding this boat and I have come across a pesky problem that won't seem to go away and it deals with the low rpm idle. While on the trailer in the water I have full rpm range from 1200- 5100 rpm and she sings at 4800, but when the throttle returns to neutral 610-700 rpm it dies. Turn off the key switch and back on to let the fuel pump prime and it turns over and cranks without issue but still needs to be have the throttle around 8-11%(diagnostic tool read out) to not die.
​​​​
​​
steps taken so far:
1. Replaced fuel filter
2. Changed iac
-bypassed iac and generated iac fault
​​​ -new iac works, tested through diagnostic tool
3. Cleaned map sensor
-bypassed map and motor ran rich and generated fault code.
-cleared code and restarted engine
​​​​​4. Read PCM fault codes
22 warning horn output
94 pitot pressure low speed sensor (gps speed)
75 fuel level 1 circuit high (fuel cell not hooked up at moment)
119 steering position circuit
130 trim sensor circuit high
193 shift anticipate switch fault
(BW transmission dosent need shift switch from my understanding)
5. Cleared codes
6. Hooked up shift switch int switch and fault code still is generated even though with diagnostic tool it shows in gear and neutral and does not retard the engine at all when pressed.
7. Checked fuel pressure and is around 44 psi.
​​​​​​​8. No vaccum leaks

I have spent days going through the archives and still haven't made any head way with this motor and Im struggling with this as everything but the idle seems to be working fine for the particular application.

If there is any other info I can provide with the exception of the SN let me know.

Thanks in advance for the help!

 

[muc]

Have you replaced the IAC muffler? Tried running it without the muffler?
Have you checked both hoses going to the IAC for blockage?
Are you confusing the shift interrupt switch with the shift anticipate switch?
The transmission doesn’t need the anticipate switch, but the engine does.
22 and 193 are the only codes you need to worry about.
What does the scan tool read for available power %?
What brand of scan tool are you using? There maybe some more tests that can be run to help find the problem.

And welcome to the board!

 

[Captn_carroll]

Have you replaced the IAC muffler? Tried running it without the muffler?
Have you checked both hoses going to the IAC for blockage?
Are you confusing the shift interrupt switch with the shift anticipate switch?
The transmission doesn’t need the anticipate switch, but the engine does.
22 and 193 are the only codes you need to worry about.
What does the scan tool read for available power %?
What brand of scan tool are you using? There maybe some more tests that can be run to help find the problem.

And welcome to the board!

Thanks for the input Muc!

1. I had the flame arrestor off and didn't see any type of iac muffler in either of ports in the air intake.

2. The passage ways in the hoses are free from any debris or blockage.

3. You have a valid point with the interrupt/anticipate switch. I'm looking into this one now...

4. 100% power available, she's got a good loud healthy v8 sound under load while in the water, one of the reasons I chose to do the restore.

5. Tech mate pro diagnostic tool.

Much appreciated on the timely response Muc!

 

[Captn_carroll]

Are you confusing the shift interrupt switch with the shift anticipate switch?
The transmission doesn’t need the anticipate switch, but the engine does.

Muc, I've gone back and looked at the interrupt/anticipate switch. Originally when i purchased the boat there was no interrupt /anticipate switch even installed on the motor. I pulled a working switch from my 4.3 and plugged it up to the harness and checked in the scan tool and it read neutral when not pressed and in gear when pressed and the motor still has the idle issue in and out of gear. I cleared the faults and restarted the engine and the faults again reappeared. I started the engine and had it idle around 1200 rpm and pressed(activated) the switch confirmed by the scanner and the motor didn't even drop rpm when activating the switch.

Not sure if that's what you're inferring about the 193 code fault on the interrupt/anticipate switch.

again thank you for the help Muc, it is greatly appreciated!

 

[Fun Times]

2003 mercruiser 5.7 mag mpi alpha
Rebuilt borg warner 71c direct drive transmission
275.7 hrs.
193 shift anticipate switch fault
(BW transmission dosent need shift switch from my understanding)

Is this a new to you set up or has this engine combo been running for 275.7 hrs without this idle issue?
If it's a new combination issue then a few possible issues come to mind.

1) Would be while you may not need a shift switch for this application it sounds like you may be missing the jumper connector assembly at the wiring harness where it would plug into the shift interrupt switch...
Basically Bravo and MIE engine models need the connector jumper to help the ECM know what transmission is being used ,etc. while the Alpha uses the switch....This should be the reason you're getting a 193 fault code which states in the book: Shift Anticipate Switch Fault, A shift fault has occurred. Shift interrupt switch active at incorrect time. Issues could be, Wiring problem, Mechanical linkage problem, Faulty Shift Switch, And not listed because not normal, a missing jumper plug at the wiring harness should set this code too.

If this is the case then depending on not knowing exactly what model you have, it may be difficult to figure out what jumper connector your engine would utilize correctly/in order to help receive the correct one as there are 3 to choose from now..,
Item number 11, http://www.hardin-marine.com/s-1425-lifting-brackets-and-wiring-harness.aspx

11	805592A1					CONNECTOR ASSEMBLY (White Wire)	1		SN# 0M364615 & Below
11	830796A1					CONNECTOR ASSEMBLY (Black Wire)	1
11	864337A1					CONNECTOR, Black, Jumper	1

When the throttle returns to neutral 610-700 rpm it dies. Turn off the key switch and back on to let the fuel pump prime and it turns over and cranks without issue but still needs to be have the throttle around 8-11%(diagnostic tool read out) to not die.

​2) Would be maybe the ECM isn't calibrated enough to handle the load of the Brog transmission and more calibrated for an Alpha drive....There are many ECM's from merc for each engine combination.
3) Could be there might not be enough air bypass within the throttle plate to handle a load change between the two designs....It only dies when in the water/in gear? but out of water on the garden hose will it idle normal?
4) Could be maybe the HVS distributor assembly isn't "Phased in" correctly especially if the distributor was removed/disturbed at all recently.
5) What does the throttle position sensor say voltage and percentage say at idle/closed position even key on engine off if you can't get a read with the engine running.

https://forums.iboats.com/forum/eng...out-into-gear-code-193-shift-anticipate-fault

 

[Captn_carroll]

Is this a new to you set up or has this engine combo been running for 275.7 hrs without this idle issue?
If it's a new combination issue then a few possible issues come to mind.

1) Would be while you may not need a shift switch for this application it sounds like you may be missing the jumper connector assembly at the wiring harness where it would plug into the shift interrupt switch...
Basically Bravo and MIE engine models need the connector jumper to help the ECM know what transmission is being used ,etc. while the Alpha uses the switch....This should be the reason you're getting a 193 fault code which states in the book: Shift Anticipate Switch Fault, A shift fault has occurred. Shift interrupt switch active at incorrect time. Issues could be, Wiring problem, Mechanical linkage problem, Faulty Shift Switch, And not listed because not normal, a missing jumper plug at the wiring harness should set this code too.

If this is the case then depending on not knowing exactly what model you have, it may be difficult to figure out what jumper connector your engine would utilize correctly/in order to help receive the correct one as there are 3 to choose from now..,
Item number 11.

​2) Would be maybe the ECM isn't calibrated enough to handle the load of the Brog transmission and more calibrated for an Alpha drive....There are many ECM's from merc for each engine combination.
3) Could be there might not be enough air bypass within the throttle plate to handle a load change between the two designs....It only dies when in the water/in gear? but out of water on the garden hose will it idle normal?
4) Could be maybe the HVS distributor assembly isn't "Phased in" correctly especially if the distributor was removed/disturbed at all recently.
5) What does the throttle position sensor say voltage and percentage say at idle/closed position even key on engine off if you can't get a read with the engine running.

https://forums.iboats.com/forum/eng...out-into-gear-code-193-shift-anticipate-fault

_____


-275.7 hour engine time
The previous owner was fed up with the performance of the idle and ran the boat at a high idle, im guessing thats why the transmission was rebuilt. I spoke with the shop that did the work and they said that the motor was a headache from the word "GO' and that it would never idled right. I have ridden in the boat with the idle issue and it performs well beyond what i expected, the boat was doing over 60 mph at 4600 rpm and sounded AWESOME! so it has been in that config since it was put into that boat.

-Connector/Jumper
I attached the switch to the harness and inside the diagnostic tool i could see the open/close or activated mode when i pressed the button but the motor rpm didnt drop at all.

2. ive spoken with mercury and without a sn# to go off of its kind of a shot in the dark... i did talk to a master mechanic in mercs racing division and he mentioned that i should have the MIE ecm vs the alpha ecm. He recommended to have it flashed for the MIE for different reasons.

3. how would i check the air bypass? it stalls on the trailer with water hose and in water. It stalls with the transmission hooked up and in neutral, currently i have the transmission disconnected from the shift cable. any time the motor/throttle is in the neutral position it stalls then dies.

4. to my knowledge the distributor has not been replaced. if there was an issue with the distributor would it function from 1200 to 5000 rpm with out an issue?

5. i will have to get the scan tool again but from what i recall, the tps was reading less than 2% on the scanner. i do know for a fact that i removed the throttle cable and pushed the throttle wide open and i could see the % move accordingly. idle was very low and WOT registered 100%.

Much appreciated Fun Times!

 

[Captn_carroll]

2003 mercruiser ecm question: alpha vs mie

hello all!

i recently acquired a project boat that is equipped with a 2003 350 mag mpi w/ alpha ecm (no serial number) paired with a direct drive transmission.

the motor was pulled from a wellcraft setup with an alpha sterndrive setup that worked for over 200 hours without issue.

the old configuration originally had a 327 powering the direct drive transmission. The 350 mag mpi motor w/alpha ecm was installed and runs great at WOT, however it has trouble in the idle range of 600-900 rpm. since that motor was paired with that transmission it has never idled without issue.

i have replaced the aic, checked for vacuum loss, cleaned the map, hooked up a shift anticipate switch (not installed on direct drive), checked the tps with scan tool and cleared all codes that were being thrown by the motor. the only code that was being thrown that is related to the shift switch is 193. after hooking up the switch, the scanner would read proper input for in gear/neutral but the motor would still stall out at idle.

Im wondering if the alpha ecm would have anything to do with the idle issue since theres very little resistance on an idling alpha setup while in neutral compared to a direct drive transmission at idle.

Any and all help is appreciated!

THANKS IN ADVANCE!

 

[Fun Times]

Welcome back Captn_carroll , I took the liberty of merging your new topic into your original one since it's pretty much the same topic so lets see if we can continue to help you out in here with this one...Thanks.
-------------------------------------------------------------------------------

-275.7 hour engine time
The previous owner was fed up with the performance of the idle and ran the boat at a high idle, im guessing thats why the transmission was rebuilt. I spoke with the shop that did the work and they said that the motor was a headache from the word "GO' and that it would never idled right. I have ridden in the boat with the idle issue and it performs well beyond what i expected, the boat was doing over 60 mph at 4600 rpm and sounded AWESOME! so it has been in that config since it was put into that boat.

Gotcha thanks for that update.

-

Connector/Jumper
I attached the switch to the harness and inside the diagnostic tool i could see the open/close or activated mode when i pressed the button but the motor rpm didn't drop at all.

I'm relatively pretty sure that in this case the jumper connector mentioned above should be your issue with the 193 fault code and possibly part of the low idle stalling issue too...It's mostly a shifting timing issue the ECM is picking up that is not happening at the correct time/RPM, etc...Just plugging in the shift switch and pushing the button isn't really going to be the same as the jumper connector in this case.

You may be able to preform a test to see if the idle issues changes at all. If you can get the following link open, on page 3 there's a diagram to show you how to bypass the shift switch at the wiring harness by jumping A and C. Won't hurt to give it a try.
http://marinemechanic.com/merc/distr...fi-nostart.PDF

2. ive spoken with mercury and without a sn# to go off of its kind of a shot in the dark... i did talk to a master mechanic in mercs racing division and he mentioned that i should have the MIE ecm vs the alpha ecm. He recommended to have it flashed for the MIE for different reasons.

The mercs racing division team are really up on their technology standards so I'm sure you talked to a pretty knowledgeable person to help get you headed in a right direction.

Yes you truly should have your ECM re-calibrated for an MIE engine as essentially that is what you have...Not an alpha engine/drive combo and was one of my first thoughts of a possible stalling issue while reading your descriptions.

3. how would i check the air bypass? it stalls on the trailer with water hose and in water. It stalls with the transmission hooked up and in neutral, currently i have the transmission disconnected from the shift cable. any time the motor/throttle is in the neutral position it stalls then dies.

A scan tool helps so you know where the TPS settings are to start with then if your throttle body has a set screw to help adjust the throttle cam assembly; try going up "some" to see if it will help with the stalling issue.
The throttle screw is usually set at the factory for your engine combo/ECM program and not recommended to readjust the set screw but again your engine combo isn't set up properly so you may have to change the idle setting screw a bit depending how you go about things for testing, etc. etc..

In years past there were times where it became necessary to drill a small hole into the throttle body plate to allow more air to the engine so it won't die out at idle....So with that if money isn't a big set back with you to at least try, I'd say you could try buying an old throttle body and drill a small hole to start in the butterfly section and slowly go bigger until it has seem to have helped solve the idle problems. Then either save your original throttle body or drill the correct size hole in yours if all works out and you want to keep using the original body due to overall component conditions, etc..
https://www.ebay.com/sch/i.html?_fro...70T+mercruiser

^ Now in saying all that regarding the throttle body, bear in mind that some of these parameters may change again if you get your ECM flashed so don't drill your original one just yet if you end up buying an experimental tester throttle body... Also keep track of how many turns you go on the idle set screw and knowing what the numbers for the TPS reads.

4. to my knowledge the distributor has not been replaced. if there was an issue with the distributor would it function from 1200 to 5000 rpm with out an issue?

With this setup it's still a considerable possibility for you to have idle issues but run okay up top.

Next time you're in the boat look carefully at the distributor shaft hold down bolt to see if the paint seems to have been disturbed by a wrench...If disturbed then it may help tell you if you need to go down that path of trying a re-phasing method which isn't done with a timing light on this engine as long as it's truly an 2003 engine model all for good measure this would be.

5. i will have to get the scan tool again but from what i recall, the tps was reading less than 2% on the scanner. i do know for a fact that i removed the throttle cable and pushed the throttle wide open and i could see the % move accordingly. idle was very low and WOT registered 100%

Again you might have to bump those TPS numbers up a bit but hopefully not a lot.

You'll also want to watch the timing advance number bounce around too with the scan tool connected. You don't want to get to high with the timing advance numbers at normal idle conditions.

 

[Captn_carroll]

thanks for input on the shift anticipate switch, i will take a look at the schematic to see about bypassing the the switch. I am going to send the ECM to a guy recommended by merc to have the ECM flashed to the correct module settings for the current application with the direct drive transmission.

Much Appreciated Fun Times!

 

[Fun Times]

I am going to send the ECM to a guy recommended by merc to have the ECM flashed to the correct module settings for the current application with the direct drive transmission.

May I ask who they recommend?

Also you may as well do any other testing's that may be needed after the re-flash so they don't hinder each other....But you will need the jumper either way....Maybe see if they recommended what one.

 

[Captn_carroll]

May I ask who they recommend?

Howdy! i sent my ECM off to OBD Diagnostics (http://obd1.com/allinone.asp), i had it flashed from the alpha programming to the Mie programming. I took it out of the box and then plugged it up and bolted it down and i started the engine. the idle issue is solved. no codes are being thrown by the ecm and all is good.

If you need any ecm work done, call OBD Diagnostics and ask for Bob. The Merc Racing Division highly recommended him and i can attest to the first class work and speed with my ecm.

now its on to sanding the hull and getting a new fresh coat of gelcoat an some graphics.

THANKS TO ALL WHO HELPED!