454 MPI Timing

[GL2238]

Can anyone provide the timing angle for the 2000, 2001 454 MPI at the following: idle (700), 2000, 3000, 4000 RPM. I believe the ECM controller is at fault. Current timing measurements indicate a change from 26 deg at 2500 RPM down to 14 deg at 3600 RPM. All sensors are normal. The powerplant is a B3 with 24 Pitch prop. WOT is 3600 and should be 4300-4600 with the 24P prop.<br />Boat is 2001 Sea Ray 26' Sundancer. I have found other postings that indicate that some of the ECMs of this era were recalled by Mercruiser and were exchanged or reprogrammed but I cannot locate any specific service notices other than in "97.

 

[newport dave]

Re: 454 MPI Timing

Are you checking the timing with a timing light? The ECM may be retarding the timing due to knock sensor input. Have you tested it with knock sensors disconnected?<br /><br />In your other thread you mentioned that the mechanics thought the ECM was limiting RPM due to input from oil presssure or drive lube sensors being triggered. After double checking the Merc manual, they say your engine should not have any RPM reduction capability. It has to be something else causing the RPM loss.<br /><br />If you really suspect that the problem is the ECM timing advance (or lack thereof) that is causing your problem, you can try running in "Distributor Module Mode". Meaning the ECM is not controlling the ignition timing, the ignition module is using it's internal advance curve. <br /><br />To run in Distributor Module Mode, disconnect the white wire (Ignition Control circuit) from the four wire connector on the distributor. To do it right requires a pin tool to remove the terminal from the four pin connector, but it can be cut and reconnected if done properly.<br /><br />Dave

 

[waterone1@aol.com]

Re: 454 MPI Timing

I would be looking at every other possibility before suspecting the ECM. If that is the MEFI3, the replacement is over $1200.00 ( the original is N.L.A.). How about starting at the begining...engine serial number would help, so we know exactly what you have. What became of the general 1 and 2 codes you had in your last post ? Were there any two digit codes ? Do you have the ability to take the boat out with a scan tool connected to it ? <br /><br />You are right, you should not have a fall of 12 degrees from 2600 to 3600. You should have about 31degrees @ 2600 and 26 degrees @ 3600. As Dave pointed out this could be due to the knock sensor kicking in or you could already be operating in the distributer mode (it will not supply as much advance). Did you just get this boat ? When did it run right last ? What work has been done to it ? Is the prop in good condition ? Is the bottom clean ? Have you done a fuel rail pressure test (lean condition will cause knock and timing retard) ?

 

[GL2238]

Re: 454 MPI Timing

Thank you all for help. With Merc Tech on board and tech hand-held attached, three WOT runs were made. All sensors checked OK. I will check on the Engine ID. The (1, 2) codes, it turned out, are related to auto use, not marine according to the tech. The info from Newport Dave sounds like the next step. Info: I have been scanning other threads on this subject and now have info on 26 other folks with exactly the same problem. Interesting that it is the same power plant, same year (2000-2001, and same outdrive (B3)and same boat manuf. (Sea Ray) In all but seven cases, Merc replaced the ECMs. The rest are having difficulties with Merc and I suspect legal action. I will be directing correspondence to Merc shortly. I am tired of pouring money into this system. I wish I had my previous 454 MPI Volvo Duo-Prop "24 Four Winns" on this boat.

 

[newport dave]

Re: 454 MPI Timing

GL2238,<br />Check the following link about MEFI3 systems. It says that the gear lube monitor (sterndrive) or trans o/t (inboard) will trigger a General Warning 1 or 2, respectivly. But there should never be both.<br /><br /> http://www.boatfix.com/merc/Bullet/99/99_03.pdf <br /><br />Please keep the info coming on your research into this problem.<br /><br />Not sure if it is related, but Searays of those years had the "IPX System Monitor" that was connected to the ECM and was supposed to provide user warnings of engine problems. It was unique to Searay. I'm sure you are aware of this, but just in case, I thought I would mention it. <br /><br />There is a guy over on OSO that is having a very similar problem, but it's not a Searay.<br /><br />Dave

 

[GL2238]

Re: 454 MPI Timing

All of the manuals on the power plant from Sea Ray and third parties have the color codes for the wires but not the signal names? Does anyone have the wires designated by signal name in and out of the ECM? This would be most helpful. I am going to disconnect the ECM Ign Module signal this weekend to check for sure that it is the ECM. Tnx for the info New Port Dave.

 

[Don S]

Re: 454 MPI Timing

Did this boat ever run at the correct WOT rpm?<br /><br />If you disconnect the ign module from the ECM, it won't run.<br /><br />I would sure try a different set of props with lower pitch before starting with the ECM.

 

[GL2238]

Re: 454 MPI Timing

Don: The boat never ran at the correct RPM but did on one test run reach 4K. Some runs were maxed out at 3400 but most times WOT is limited to 3600. Prop was changed do a 20 from the manuf supplied 24 Pitch and no change in WOT. The lead was cut today which bypasses the ECM control of the advance. Test run went to approx 4450 at 39MPH+ GPS. Now I have to find out why the ECM is messing up. It has got to be one of the sensor inputs. I can't leave it this way because the timing, using the ign module internal advance program is causing a timing lead of 15 degrees minimum and it should be a max of 12 typically 8 BDC. This makes it hard to start. If I ground the pigtail (white) lead for setting the base timing, it is 10 degrees and I am not going to tamper with the mechanical position of the distributor. The MEFI3 is no longer available from Mercruiser as it has been replaced by the MEFI4 (I wonder why) [laugh]. Just thinking it might be a SW glitch in the ECM. Nice to know I can work around it. I am developing a circuit using a PIC uP to read the MAP, throttle position sensor and tach input to emulate the ECM. Should be an intersting experiment. Tnx to everyone for suggestions. Another interesting note is that the ECN, when the RPM is less than 300 RPM i.e starting, the bypass is set to active just like when the pigtail is grounded for base idle setup. So it seams the Ign module has some hangups as well. (sigh) At least my powerplant is A-OK. <br /><br />Jerry

 

[Don S]

Re: 454 MPI Timing

What's the engine serial number.<br />In your original post you stated 2000 or 2001, well, there are 2 completely different systems and manuals. So it's time to find out exactly what you have. That is why Mercruiser uses serial numbers. They don't go by years, because you may have a 2000 engine in a 2001 boat on some you could even have a 99 model.<br />Most parts for the MEFI-3 are still available. Just not sure what you have.

 

[newport dave]

Re: 454 MPI Timing

Originally posted by GL2238:<br /> I am developing a circuit using a PIC uP to read the MAP, throttle position sensor and tach input to emulate the ECM. Should be an intersting experiment.

Could you give more details? Don't know what your budget is, but if you are serious about data acquisition and analysis, Diacom software is the way to go (it's cheaper than an ECM). <br /><br />

Originally posted by GL2238:<br />Another interesting note is that the ECN, when the RPM is less than 300 RPM i.e starting, the bypass is set to active just like when the pigtail is grounded for base idle setup. So it seams the Ign module has some hangups as well.

Nothing wrong with the Ignition Module. The ECM will energize the bypass circuit and use the timing signal from the ECM (through the Ignition Control circuit) in Run Mode or Base timing Mode. The difference is that in Run Mode the ECM alters the timing of the reference signal it gets from the Ignition Module before sending it back, in Base Timing Mode it does not. Either way, it is normal for the Bypass circuit to be powered up.<br /><br />Dave

 

[GL2238]

Re: 454 MPI Timing

Tnx for info. I was on the Rinda Site thinking of buying the Mercruiser scanner or the Diacom SW for my laptop that you noted. What I was thinking of was developing a replacement for the IGN timing part of the ECM just for experimenting sake. I have designed control loops for projects other than marine and am well versed in the theory and hardware. At least I now know that the boat will perform as advertised. Relative to the Diacom you need propriatary data to support some of the SW applications in Diacom that must be obtained from Mercruiser (fat chance unless you are a registered Mercruiser service person). Seems like the Rinda Mercruiser scanner is the way to go.

 

[newport dave]

Re: 454 MPI Timing

To reflash an ECM you need information from Mercruiser, but thats the only thing you can't do. I am not a Mercruiser dealer. But I often diagnose problems a Mercruiser dealer (with a handheld or DDT) was not able to diagnose. <br /><br />For problems like yours, you want to be able to monitor ALL data parameters at once. With a handheld scanner you can only monitor one or two things at once. It's like trying to drink a 5 gallon bucket of data with a shot glass. Get the Diacom software. You will be happy you did.<br /><br />Dave<br /><br />

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[GL2238]

Re: 454 MPI Timing

Dave, I'm sold. I will order tomorrow from Rinda. Being able to reflash is what I would like to do but I guess I will have to settle. By the way do you know of anyone who has installed the larger injectors on the 7.4L?<br /><br />My pet project will still be the development of an alternative IGN control only ECM. <br /><br />I can get a first order idea of the flash IGN portion of the MEFI ECM by noting the advance timing vs the various sensor inputs especially the MAP.<br /><br />Again Dave, tnx for your info. <br /><br />Jerry