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| MPI Engine won't idle or start w/out moving throttle https://www.smwebhead.com/phpBB3/viewtopic.php?f=11&t=9386 |
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| Author: | 90Tiger [ Mon May 28, 2012 8:54 am ] |
| Post subject: | MPI Engine won't idle or start w/out moving throttle |
I had the boat out the other day and it developed a problem. I can't get my engine to idle (5.0L MPI) or to start without moving the throttle forward and revving it. To start the engine, I have to move the throttle forward (out of gear) and let it rev. However, once I pull the throttle back to neutral/idle, it cuts off. I didn't think moving the throttle forward was necessary to start a MFI engine but I can't keep the engine running unless I start it with the throttle forward (and revving it to about 2K RPMs). I have this problem whether the boat is in the water or if using ear muffs. Boat was running fine just before this started to happen and also seems to run fine once I get it moving......to get it to move (I was out in the middle of the lake when this happened), I had to start the engine by moving the throttle forward, rev it up, then quickly pull it to the neutral throttle position and quickly throw it into gear before it died. Once moving, I didn't notice any misfiring or unusual sound from the engine. Any ideas on what the problem could be and how to fix it? UPDATE (6/2/12): Problem solved by installing new IAC. See 6/2/12 post below. |
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| Author: | Bliss36 [ Mon May 28, 2012 10:58 am ] |
| Post subject: | Re: MFI Engine won't idle or start w/out moving throttle |
Could be a bad IAC or idle air control valve on your throttle body. Sometimes they get jammed up with carbon..you could remove it(2 little torq screws), clean it with carb spray and reinstall it. Once reinstalled the pintle should move to control the air and therefore your idle. I would start there. |
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| Author: | JeffLW [ Mon May 28, 2012 12:39 pm ] |
| Post subject: | Re: MFI Engine won't idle or start w/out moving throttle |
I had this exact same problem just now. The boat ran great for about an hour and then just died when at idle. Luckly I wasn't too far from the launch I put in at. Made for a fun time getting it back to the dock.  Got it back on the trailer and am looking for answers now.I just got this boat so I'm thinking water in the fuel or just old fuel? |
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| Author: | Graham R [ Mon May 28, 2012 4:49 pm ] |
| Post subject: | Re: MFI Engine won't idle or start w/out moving throttle |
It might be the microswitch on the shifter; defective or loose; it's there to basically stop you starting the engine when not in neutral. |
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| Author: | vogs77 [ Mon May 28, 2012 7:23 pm ] |
| Post subject: | Re: MFI Engine won't idle or start w/out moving throttle |
I have a 5.0 ford with fuel injection and have the same problem right now. I just bought the boat and it seems even worse when the engine is warmed up. It will idle once I get it running sometimes. You shoud not have to open the throttle on a fuel injected engine to get it running or keep it running. I am going to start with cleaning the throttle plate and idle speed motor. I also have a light surge just off of Idle am hoping to fix with cleaning these out also. I removed my flame arrestor to clean it before I put the boat in the water because it was filthy, I also noticed crap in the throttle body but didnt have any cleaner at the time. I hope to have this done later this week so I will let you know how it goes for me. The boat runs awsome other than that and some noise I have that is yet to be found. |
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| Author: | JeffLW [ Mon May 28, 2012 7:49 pm ] |
| Post subject: | Re: MFI Engine won't idle or start w/out moving throttle |
Just found this: http://www.boatingwinnebago.com/forums/ ... ry-minute/ Pretty much discribes the problem I am having and how to fix it. New IAC valve. |
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| Author: | 90Tiger [ Tue May 29, 2012 7:53 am ] |
| Post subject: | Re: MFI Engine won't idle or start w/out moving throttle |
Thanks guys. I think I will be replacing my IAC. I took the IAC off yesterday evening and will try to clean it first. If that doesn't work, I will replace it (along with the IAC filter/muffler). Either way, I will probably order a new one today. One thing that bothers me is that my mechanic didn't/couldn't diagnose it. At the beginning of the season (de-winterization service), he said there was a beeping alarm and he thought it might be the oil sending unit, fuel sending unit or water sending unit but he didn't know which one and would have to look it over more. Since there wasn't an oil pressure problem and the engine ran, he said his first guess would be the water sending unit and said they sometimes stick a bit when they are winterized so he thought I should run it a bit to see if the problem self-corrected itself. I took the boat out for an afternoon and had no problem; however, when I took it out last Friday evening, the starting/idling problem started so I brought the boat to him and described the problem. When I talked to him the next day, he said he hadn't been able to replicate the problem (no starting or idling) using earmuffs so he still didn't know what the issue was. I dropped the boat in the lake that evening (leaving it on the trailer) and couldn't get it to start. Brought it home and hooked the muffs up to it and couldn't get it to start. It wasn't even close to starting unless I played with the throttle. I just can't see how he couldn't have been able to replicate the problem. My gut tells me that he never even tried to start it but I just feel that he should have known just from combining the symptoms I've been having.....beeping alarm plus no start/idling. Maybe time for a new mechanic?? |
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| Author: | Bliss36 [ Tue May 29, 2012 8:15 am ] |
| Post subject: | Re: MFI Engine won't idle or start w/out moving throttle |
I bought a scanner adapter a month ago, and if you have a laptop or net book it might be a good tool to keep in your arsenal. I like the fact it shows live data not just codes. It's pretty generic but gets the job done for only $195.00 http://www.webpg.net/sc/details.asp?item=mefiscan1 Also I had to call their tech support to help set it up and they were great to deal with! |
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| Author: | Jafo4U [ Tue May 29, 2012 8:15 am ] |
| Post subject: | Re: MFI Engine won't idle or start w/out moving throttle |
Bliss36 wrote: Could be a bad IAC or idle air control valve on your throttle body. Sometimes they get jammed up with carbon..you could remove it(2 little torq screws), clean it with carb spray and reinstall it. Once reinstalled the pintle should move to control the air and therefore your idle. I would start there. +1 That is exactly what I was going to say I had the same problem on my mustang it was very annoying but easy to fix. |
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| Author: | 90Tiger [ Sat Jun 02, 2012 9:07 pm ] |
| Post subject: | Re: MPI Engine won't idle or start w/out moving throttle |
Update I removed and cleaned my old IAC reinstalling it with a new gasket and IAC muffler. No go. Removed the old IAC and installed the new one. Engine fired right up  . I just started it on the trailer (without muffs) and didn't get a chance to water test it but I couldn't even get it to start or idle with the old IAC so I am hopeful the problem is solved. I was hoping that cleaning the old one would work giving me a spare (the new one) but that plan didn't work.I ended up ordering the new IAC, gasket (2) and muffler (2) from Wholesale Marine. Got a price match to another website from Wholesale Marine on the IAC. I also ordered a 10-micron fuel filter. I was a bit disappointed when I received the package from Wholesale Marine and they had taken the liberty of "upgrading" me from a Sierra 10-micron filter to a Quicksilver 25-micron filter since the Sierra was out of stock even though their website showed it as in stock  . I was even more disappointed that the IAC gasket was not in the shipment even though their website showed it as in stock . When I called them, they had no idea when they would get the gasket in stock. The rep I talked to didn't seem to comprehend that going from a 10-micron filter to a 25-micron filter didn't sound much like an "upgrade" to me but offered to take the 25-micron filter back.....at my expense. Nor did she seem to understand that the gasket was a necessary part. Fortunately, I was able to source a new gasket about 1/2 hour from my home. It was almost 2 1/2 times the Wholesale Marine price but we are only talking $3 versus $1.25 so I can live with that.Thanks to everyone who gave me the advice and steered me in the right direction with this problem. |
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| Author: | Bliss36 [ Sat Jun 02, 2012 10:13 pm ] |
| Post subject: | Re: MPI Engine won't idle or start w/out moving throttle |
Thanks for the update!! Glad to hear you got it fixed
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