Idle air control and tps sensors

[bud37]

After replacing one or both of these sensors , is there a procedure to tell the ecu ( mefi 3-4 ) it has a new sensor like key on switching etc or are you good to go just by replacing....Thanks don't have the pertinent manual for this.....2001 merc 6.2, # OL 67xxxx......Thanks..... ....

[Viper]

Qr Bbpost After replacing one or both of these sensors , is there a procedure to tell the ecu ( mefi 3-4 ) it has a new sensor...

No, however if there is a fault code, the code must be cleared or it may be operating in default mode rather than using active inputs.

[bud37]

Thanks Viper, while in Florida this winter I was thinking to get some parts and was wondering if the automotive parts that cross for these ( IAC and TPS ), function the same as the marine versions, do you have any experience with this......
Other question is can the fault codes be cleared by key switches , just disconnecting the battery, or do I need a code reader??.....

[Midnight Sun]

I think I can help you out on the IAC valve. On my previous boat I had twin 383's and went through several of these along with many others at my marina and at least 2 other boating friends. Very problematic to say the least. My originals went and so did the replacements however after installing the automotive equivalent, no issues whatsoever. The automotive part actually lasts and cost 4x less. Do double check but I am almost positive you have a 862998 like this. http://www.ebay.com/itm/Mercruiser-Idle ... jw&vxp=mtr The replacement for that model from the automotive world is AC423T like this. http://www.ebay.com/itm/Fuel-Injection- ... e3&vxp=mtr

[bud37]

Thanks MSun, I had seen some that had some sort of spring in them that was different from the marine version, but the AC one pictured there looks right..I am still trying to find the right number for that part for my serial number sequence.......I always like spares around cause the engines don't like the throttles pulled back to idle fast ( but not all the time ), I have to move the levers slowly and all is well, they start and run great.What did you have for symptoms if you don't mind me asking??.......

[Midnight Sun]

One time was on my way to Georgian Bay in the Trent system. Left a lock and the engine died, no warning or symptoms, would not start. Showed up on my MFD as "faulty IAC" so a no brainer there, had a spare on board. This is how most of them went. One time I was cruising up on plane at around 32mph and the same message came up on the MFD, thought not much of it until I slowed down and the engine died, no start. Again had one on board, 5 min swap. Others I have talked to have had the same symptoms with 1 exception, his would idle roughly and give 2 beeps every 5mins or so but it still ran well at higher speed.

[bud37]

Finally found some part numbers for my engine serial numbers,it shows the IAC as 803149, TPS as 803148...there seems to be a change in about 2001-2002 with the ecm's, then the part numbers change .....so I guess I will try to cross those to see what I find...the cross to the AC 423t helped me to find some info...

[Midnightsun]

Makes sense, my engines were 2007 model year. Happy hunting.

[Viper]

Been a while since I worked on a MEFI but if I recall, I don't think a faulty IAC will set a code. Don't quote me on that but the later ECMs do. I mentioned the fault code topic because MEFIs don't clear some of them ("Sticky" fault codes) automatically so you could be running with a stored fault that causes the engine to run in a default mode. You need to hook up a scan tool and put it on Service Mode then set ignition to ON and move throttle to WOT then back to clear a code. You can do it without the tool by hot-wiring a couple of pins in the Data Link connector but I can't remember off the top of my head which ones. I'd have to look at my notes. A "Sticky" fault code must be cleared manually while a "Non Sticky" code will clear itself once the faulty is corrected.

For a MEFI, you should consider purchasing a CodeMate from Rinda. They're not expensive but are invaluable in checking for codes and clearing them. Every MEFI boat should have one on board. They give a series of flashing LEDs to indicate which codes are active. There are more expensive units that have text and menus allowing you to perform some diagnostics but they can get pricey.

BTW, once replaced, I've never had any Merc IACs fail in short order. Can you get an automotive replacement? Probably, they're not made by Merc so I'm sure they're interchangeable and likely made by the same manufacturer. If you're going that route, just make sure it's the exact same spec and that it doesn't just look the same or it won't function as it should. The computer is counting on it meeting a certain spec as it must achieve a travel distance based on the signal count the computer delivers to open or close a certain amount. It must be precise.

[bud37]

So I actually found a cross for the IAC ,90's or so gm trucks,vans, but there are four pins, not that much cheaper either and I have to agree there really is no way to know whether they work at the same voltages.My problem is that I didn't get the old stuff out, got sick and by the time that was over the snow was here, now I couldn't get within 100 yds (without a snow machine), don't want to buy stuff and find out it is wrong ap.The merc TPS is made in Canada, thats something heh .One thing I do know is I have the MEFI 3-4.

Regarding the scan tool, I really would like to get one and will....sent an e mail to Rinda to see if they had anything in the works for Macs and have been asking around to see if anyone is selling their diagnostics stuff but no luck there.I really wonder if you had the adaptor would an OBD code reader work (got one of those).

Engines run great except for that intermittent stall, I will clean everything in the spring and go from there, just thought to get some spares......