01' MCM5.0 EFI runs rough

[shmart2]

Re: 01' MCM5.0 EFI runs rough

I have no idea why the double post keeps happening. I have only clicked the reply key ONCE each time.<br />The boat is still in the slip and as I mentioned, seems to run rough even at idle, under no load, in the slip, just after starting. I'm just trying to eliminate low tech possibilities, and the possible clogged vent is an easy test. If she runs OK, either with just checking this, and with a new coil, I can take the boat down the no-wake zone and out in the river for a test. Also, as she is to be hauled a week from tomorrow, this will also allow me to pump out the holding tank at the marina next door, as our marina has no pump out facilities. We were on the way to do this the last time out, when she starting running rough, and I thought she may stall so headed back to the slip. My question was whether or not the fact that she runs rough and seems to want to stall all the time now, not after 45 or so minutes under load, this would tell us anything about the coil. I did hear a loud crackling sound when trying to speed up when it first occured, which I believe was the coil arcing. I know that I will most likely not resolve this until spring, but just trying to do what I can now. If I had a trailer, I would just take her to the Merc shop now, but since that will be complicated and a PIA in the spring, am hoping to avoid. Obviously, the most important thing is that she is winterized on time. Thanks again for all of the help, Eric

 

[shmart2]

Re: 01' MCM5.0 EFI runs rough

I have no idea why the double post keeps happening. I have only clicked the reply key ONCE each time.<br />The boat is still in the slip and as I mentioned, seems to run rough even at idle, under no load, in the slip, just after starting. I'm just trying to eliminate low tech possibilities, and the possible clogged vent is an easy test. If she runs OK, either with just checking this, and with a new coil, I can take the boat down the no-wake zone and out in the river for a test. Also, as she is to be hauled a week from tomorrow, this will also allow me to pump out the holding tank at the marina next door, as our marina has no pump out facilities. We were on the way to do this the last time out, when she starting running rough, and I thought she may stall so headed back to the slip. My question was whether or not the fact that she runs rough and seems to want to stall all the time now, not after 45 or so minutes under load, this would tell us anything about the coil. I did hear a loud crackling sound when trying to speed up when it first occured, which I believe was the coil arcing. I know that I will most likely not resolve this until spring, but just trying to do what I can now. If I had a trailer, I would just take her to the Merc shop now, but since that will be complicated and a PIA in the spring, am hoping to avoid. Obviously, the most important thing is that she is winterized on time. Thanks again for all of the help, Eric

 

[rodbolt]

Re: 01' MCM5.0 EFI runs rough

hello<br /> if you haver the old style oil filled coil, looks like a can, the problems usually are an arc between the coil secondary and the coil primary. as the missfie occurs the computer goes brain dead, all it sees is a lack of proper RPM and will adjust the Idle Aic Control, IAC, in the throttle body and increase the fuel pulsewitdh. this leads to wet fouled plugs since it adds fuel trying to maintain a preset RPM and what is goping in isnt burning properly. also you will hear the IAC air screaming in the throttle body.while its idling place a screwdriver between the secondary and primary posts without touching any of them. if it arcs its bad.<br /> good luck and keep posting

 

[Fishermark]

Re: 01' MCM5.0 EFI runs rough

I can probably help with the double post anyway <br /><br />After you post and hit reply, do not use the "back" arrow to go back and see your post - click on the "go" button on the bottom of the page.

 

[shmart2]

Re: 01' MCM5.0 EFI runs rough

Fishermark- Thanks, I did indeed hit the back button, sorry all.<br />rodbolt- Thanks for the coil info. I just got home from the marina. I sprung for the new coil and installed it after checking the possible clogged fuel vent by running at idle in the slip for awhile. I saw no problem with the vent- I ran with it on tightly and very loose, no difference. I understand that this may not show up as a problem unless the boat is under load, so have not completely ruled it out, but I don't think this is the problem. Then I replaced the coil. The boat started easilly but still seemed to have a slight miss- couldn't here it unless the engine cover was open. Ran her for awhile again at idle. My thought was that since the plugs may still be wet from last time, that it may take a few minutes of running and some heat to clear up. All seemed fine after 10 minutes or so , and I took her down the no-wake zone. Made it most of the way out, about 1/4 to 1/2 mile, and she SUDDENLY stalled. I restarted, turned around and STRUGGLED to get back. She stalled MANY times and both boat batteries AND my portable jump starter, which was fully charged this morning, were almost out of juice the last time she stalled. It felt as though about 2 cylinders were firing and the only way to prevent more stalls was to constantly "goose" the throttle. It seems that nothing I have done thus far has made any difference, and the problem is WORSE. I know that what I have already done is a basic tune-up, the only unnessisary item so far is the coil. Also, I spoke to the local Sea Ray dealer and the service manager thought it may be the ECM, but they can't even look at it until some time next year- don't even get me started on that topic...But, I can rent a trailer from them in the spring and take it to the local Merc dealer, the same one mentioned in earlier posts, as they too recommend them. At this point, I realize that it will probably have to go to the dealer but am still open to suggestions. The fuel pickup has not been addressed. I looked at the fitting where it leaves the tank but it appears to have a threaded portion that comes up from the tank. Being unfamiliar, I thought I should be armed with more info.I tryed to buy a service manual from 3 different boat stores and noone had one. Our last boat had a Merc 3.0 Alpha 1, and I gave that manual to the guy who bought it. I'm sure some info would be helpful in this case. Thanks again, and any additional info would be greatly appreciated. Eric

 

[rodbolt]

Re: 01' MCM5.0 EFI runs rough

get an automotive(oh horrors) basic EFI manual. the systems all all basically the same with some differences for emissions and drivability and there are some good basic EFI tech handbooks avalible. do not use the automotive book for troubleshooting just for gaining an understanding of what is happening on your engine, I will bet a 12 pack of your favorite beverage that the ECM is ok. this stuff aint voodoo.<br /> usually its a bad connection someplace and usually caused while hunting another problem. does your fuel pump run for 2-5 seconds when the key is turned on?<br /> after startup the fuel pump control switch goes through a pressure switch normally located just above the oil filter pad on the lower port side of the block. when in start mode that swich is bypassed and all pumps run on the start circuit. while it was struggling could you hear air whistling down the intake tract ?

 

[rodbolt]

Re: 01' MCM5.0 EFI runs rough

hello <br />another basic tool you can buy or rent is the fuel rail pressure gauge. they are not expensive and work well. post back your engine seriel# as it did not show up on my parts express

 

[Don S]

Re: 01' MCM5.0 EFI runs rough

Click Here For the Mercruiser website. Then on the nav bar on the left hand side click on Order a MerCruiser Manual. They are $35 each, and in a few days you will have the "REAL" manual for checking your engine. You need service manual 31. PN 90-864260001 and don't get 90-863161, that is the old #31 manual before the updates.<br /><br />One other point. A SeaRay dealer is not the only place you can go for repairs. Any Mercruiser certified dealer is capable of repairing your engine. It DOES NOT have to be SeaRay.

 

[Don S]

Re: 01' MCM5.0 EFI runs rough

Rodbolt<br />He had his SN above as OM017554. It is actually 0M017554, it's a 0M (zero number) not OM (O letter)

 

[Bondo]

Re: 01' MCM5.0 EFI runs rough

Eric,<br />Way back when you changed the Fuel Filter,<br />Did you dump the contents of the old 1 into a container,+ Look to See if there was Water,+ Crap in it ???????????????<br /><br />I suggest that you do this with the Filter that's on it Now...........<br />I'm betting you're going to find Water Again................

 

[rodbolt]

Re: 01' MCM5.0 EFI runs rough

Dons<br /> I tried it both ways and it would not accept it<br /> I may try again later. <br /> I still think its not a sensor or ECM failure. unless it was induced by the previous trouble shooting attempts.<br /> good luck and keep posting

 

[shmart2]

Re: 01' MCM5.0 EFI runs rough

Good evening all. I was at the marina again yesterday, (Sunday,) and will tell you what I did and what the boat did. Thanks again for all of your help. Also, I will then quickly summarize what I have done thus far, since there have been so many posts since the first one.<br />Yesterday I removed the water seperator/ fuel filter again and dumped the contents into a glass jar. The fuel was as clean as can be, no water or sediment. I also removed the fuel pickup and backflow valve. The screen was very clean, looked brand new. The spring-loaded ball/valve was free to move in and out as designed, and I cleaned it with Brakleen while it was out.<br />I could not find the fuel pump control switch or pressure switch. This engine has a remote oil filter which is on the port side, but<br /> may not be where I was looking. And, yes, the fuel pump runs for 2 seconds when the key is turned on. There is also a loud beep that sounds for about 1 second when the key first is turned on that I was told when we got her, tells me the fuel pump is operational. This works now just as it always has.<br />DonS- Thanks for the p/n for the manual. I will be ordering one tonite. Also, the Sea Ray dealer was almost a LAST resort. They are nearby and I got the coil from them as I wanted to make sure I got an OEM unit and they were open. Also, they charged me the same price as everyone else- just over $50 with tax, so I didn't feel ripped off.<br />Then I started her up. Started easily, idled smoothly at the same RPM as before there were any problems, 650 RPM. I allowed her to warm up at idle, and occasionally reved up for a moment to see how responsive she was. Was very responsive, would rev up to 4K or so RPM almost immediately. THEN, after 15 or so minutes, during which time I was listening closely for odd noises and monitored oil pressure and temp, (both normal,) she again SUDDENLY started to run rough and the idle began to increase to 1200-1400 RPM while still in the neutral throttle position, (was fluctuating, without my ever even touching the throttle,)and with a clear increase in air being sucked through the throttle plate. Watching the tach needle bounce around and hearing the RPM increase and fluctuate made her seem like she was POSSESSED. It was weird, but was easier to observe than in the past since I was in the slip the entire time. She did not stall but was close to it when I shut her down. Also, I removed the gas cap to eliminate the clogged vent possability.<br />To summarize, Here is what has been done so far: REPLACED Dist cap, rotor, plugs, (gapped at .045,) and coil. CLEANED fuel pickup screen and back-flow valve. Also looked carefully and squeezed wire connectors all around the engine, all seemed tight and look brand new.<br />She is to be hauled and blocked next Sunday, so most likely to resolve until spring. 2 questions:<br />1.) Should I replace the spark plug wires? Could one be bad causing the ECM to try to compensate then malfunction? When I touch them individually I feel no juice/shock.<br /><br />2.) Should I try to find a mobile tech to come out (Like a local rodbolt) or is this something that needs to be analized at a Merc dealer? <br /> Thanks again. Once again, even though the problem is not yet resolved, I have MUCH more knowledge. I am all for PM and now know, for example, how the pickup is removed/cleaned and that I have to fill up the seperator with fuel before restarting, etc... Am also planning to purchase an oil change pump so I can do it myself- a couple of times a season. All the best, Eric

 

[Don S]

Re: 01' MCM5.0 EFI runs rough

Your gonna hate me for this Eric, but I gave you the wrong service manual number earlier. It's for a 2001 MPI, not TBI. You actually need service manual 24 PN 90-861327--1. Just picked up the 31 book today and noticed the problem. Sorry bout that.<br />Trying to come up with some suggestions for you, just not having any luck just yet.

 

[shmart2]

Re: 01' MCM5.0 EFI runs rough

Good evening all. I was at the marina again yesterday, (Sunday,) and will tell you what I did and what the boat did. Thanks again for all of your help. Also, I will then quickly summarize what I have done thus far, since there have been so many posts since the first one.<br />Yesterday I removed the water seperator/ fuel filter again and dumped the contents into a glass jar. The fuel was as clean as can be, no water or sediment. I also removed the fuel pickup and backflow valve. The screen was very clean, looked brand new. The spring-loaded ball/valve was free to move in and out as designed, and I cleaned it with Brakleen while it was out.<br />I could not find the fuel pump control switch or pressure switch. This engine has a remote oil filter which is on the port side, but<br /> may not be where I was looking. And, yes, the fuel pump runs for 2 seconds when the key is turned on. There is also a loud beep that sounds for about 1 second when the key first is turned on that I was told when we got her, tells me the fuel pump is operational. This works now just as it always has.<br />DonS- Thanks for the p/n for the manual. I will be ordering one tonite. Also, the Sea Ray dealer was almost a LAST resort. They are nearby and I got the coil from them as I wanted to make sure I got an OEM unit and they were open. Also, they charged me the same price as everyone else- just over $50 with tax, so I didn't feel ripped off.<br />Then I started her up. Started easily, idled smoothly at the same RPM as before there were any problems, 650 RPM. I allowed her to warm up at idle, and occasionally reved up for a moment to see how responsive she was. Was very responsive, would rev up to 4K or so RPM almost immediately. THEN, after 15 or so minutes, during which time I was listening closely for odd noises and monitored oil pressure and temp, (both normal,) she again SUDDENLY started to run rough and the idle began to increase to 1200-1400 RPM while still in the neutral throttle position, (was fluctuating, without my ever even touching the throttle,)and with a clear increase in air being sucked through the throttle plate. Watching the tach needle bounce around and hearing the RPM increase and fluctuate made her seem like she was POSSESSED. It was weird, but was easier to observe than in the past since I was in the slip the entire time. She did not stall but was close to it when I shut her down. Also, I removed the gas cap to eliminate the clogged vent possability.<br />To summarize, Here is what has been done so far: REPLACED Dist cap, rotor, plugs, (gapped at .045,) and coil. CLEANED fuel pickup screen and back-flow valve. Also looked carefully and squeezed wire connectors all around the engine, all seemed tight and look brand new.<br />She is to be hauled and blocked next Sunday, so most likely to resolve until spring. 2 questions:<br />1.) Should I replace the spark plug wires? Could one be bad causing the ECM to try to compensate then malfunction? When I touch them individually I feel no juice/shock.<br /><br />2.) Should I try to find a mobile tech to come out (Like a local rodbolt) or is this something that needs to be analized at a Merc dealer? <br /> Thanks again. Once again, even though the problem is not yet resolved, I have MUCH more knowledge. I am all for PM and now know, for example, how the pickup is removed/cleaned and that I have to fill up the seperator with fuel before restarting, etc... Am also planning to purchase an oil change pump so I can do it myself- a couple of times a season. All the best, Eric

 

[shmart2]

Re: 01' MCM5.0 EFI runs rough

DON S- I just saw your post after checking my (rather long) post... As I mentioned, (but you probably havn't seen yet,) I was planning to order the manual tonite, so have not yet done so. All of your time is greatly appreciated. Even if I had ordered the wrong one, no big deal. Thanks again, Eric

 

[Don S]

Re: 01' MCM5.0 EFI runs rough

Glad you didn't order the wrong one.<br />While I still think you need to find a qualified tech to look at your problem before changine too many parts, I did find this service bulletin. Read it and see if sounds like your problem, perhaps you can try to duplicate it again.<br /> Service Bulletin 2000-14 <br /><br />The original sensor on your engine was replaced back on 08/18/2001 after it failed and had a no start condition.

 

[waterone1@aol.com]

Re: 01' MCM5.0 EFI runs rough

As I've said before, I have not worked on any of the newer boats that have ECM's. But I have worked on several C4 Corvette's that were so equipped. Do these work on the same principle, in that the ECM uses preset values until operating temperature is reached ? If this were a car it would seam that the O2 sensor or the MAF(in some cases MAP) is not reading right, causing either the IAC or the pulse width of the injectors to be adjusted way out of specs while the ECM is trying to get the mixture right. Do boat systems have O2 sensors? IMHO,It just sounds more fuel/mixture related than ignition related.

 

[Don S]

Re: 01' MCM5.0 EFI runs rough

Your right waterone, the problem is in finding it. And to start changing every part till you happen on the problem is the biggest problem. Without the equipment and knowhow, all you do is become a parts changer and spend a lot of money for nothing.<br />How much do you think it will cost to replace the ECM, the IAC, the MAP, the TPI, the distributor sensor, the coil, the injectors, the.......where do you stop? Only to find it's an inexpensive problem that is way hard to get at to fix. So no one looks there? But hey, you have now replaced $2000 worth of parts that weren't bad to start with and you still have the problem.<br />It doesn't matter if you work on Corvetts or Boats. You have to know how to troubleshoot the system properly to fix it properly without sending a lot of money and time just replacing good parts till you find the bad one. (If you actually do find the problem)

 

[waterone1@aol.com]

Re: 01' MCM5.0 EFI runs rough

I agree with you Don, having a scan tool or some way to "see" what the sensors are reading and what the ecm is "telling" the injectors, etc, is the way to go. I am also trying to point out that I would suspect a sensor before I would jump to the conclusion (like his marina mechanic) that the ECM or as he put it, the black box is bad. If I had to take a shot in the dark I would rather try a couple of $50.00 parts than a single part that cost $$$(not the way to run a shop, but for the do-it-yourselfer). Couldn't this problem be isolated between ignition and fuel with a timing light ? If one cylinder at a time a timming light was placed on the plug wires, couldn't we see if the ignition is firing steady (at idle) or missing ? That might point to whether it is spark or fuel related ?

 

[Dunaruna]

Re: 01' MCM5.0 EFI runs rough

Originally posted by shmart2:<br /> Then I started her up. Started easily, idled smoothly at the same RPM as before there were any problems, 650 RPM. I allowed her to warm up at idle, and occasionally reved up for a moment to see how responsive she was. Was very responsive, would rev up to 4K or so RPM almost immediately. THEN, after 15 or so minutes, during which time I was listening closely for odd noises and monitored oil pressure and temp, (both normal,) she again SUDDENLY started to run rough and the idle began to increase to 1200-1400 RPM while still in the neutral throttle position, (was fluctuating, without my ever even touching the throttle,)and with a clear increase in air being sucked through the throttle plate. Watching the tach needle bounce around and hearing the RPM increase and fluctuate made her seem like she was POSSESSED. It was weird, but was easier to observe than in the past since I was in the slip the entire time.

"In the slip the entire time". That means it happenned without load.<br /><br />Here my 2cents worth, definetely heat related, maybe coil. <br />Don, do these have TWO fuel pumps?<br /><br />Aldo