SB

iTrader: (1)

Good thread some years ago about putting into base timing and also using an LED for codes on the MEFI's.

http://www.offshoreonly.com/forums/d...%241-00-a.html

715517

I'm in a boat for now and tested the diagnostic led thing above. I got two fault codes, 33(map signal too high) and 42(ic grounded or open bypass). Also deleted the codes. I'll read the fault codes again but first i have to clean the spark plugs and maybe change the oil because of few hours only idling at harbor i think it has some fuel in oil.

MAP signal too high could be a symptom from too low vacuum when i had my secondary throttle flap too much open for a while?

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articfriends

iTrader: (1)

Mef-1s not that sophisticated, i dont think it "considers" tps vs read map signal other than for AE table for acceleration
The 98 pq 502 i mentioned earlier w setup like yours (mef-1 ecu, early, tall injectors like picture i showed) but cool fuel threw map code 33 also but in end that particular one had bad fuel regulator. So what im saying is wh r n they run like crap, rich or lesn, and sputter the map is low and throws a code . His map code never came back after fixing fuel issues.
I would however, spray something flammasble near where msp sensor seals to intake toake sure rpms atay same, no vacuum.leak giving falso map low reading.

715517

I meant the secondary flap, which isn't tps related. I adjusted it all the way closed, then the IAC was working whole time so i opened the flap, and opened it too much and idle was somewhere in 1200rpm and wouldn't come back. Now i adjusted it little bit closer.

This engine also had MAP problems a year ago(previous owner), then the map sensor was replaced. But the new map sensor didn't work at all, so they put another new map which i think works now. Moment after that the ECM went bad and they changed this 502 ECM and wiring harness. The ECM was bought from official Merc dealer/workshop and they say that it will work.

What do you think about the fault code 42?

715517

Trouble codes 33 and 42 came back when i adjusted the ignition timing. Also engine doesn't start when pins A&B are jump wired in DLC. I had to open some throttle to get it started. When dropping rpm from 1800 to idle, engine did shut off.

Also i noticed that when engine is warm, few spark wires pop off from distributor cap. Wires are new, but seems like they are installed backwards.
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AllDodge

iTrader: (1)

Check the wire colors on pins A&B, something is wrong with the wiring or the ECM I'm thinking.

With dying at idle, it may have damaged the IAC or the control of it

715517

When wiring A&B, ignition on but engine not running, IAC valve keeps some.kind of ticking sound, is it normal?

BUP

iTrader: (9)

take the engine out of base timing mode then shut the engine off plus Make sure your rpms are back to correct idle before shutting the engine down as well.

Buy the code mate tool at very least or IMO if one is working on their marine MPI engine(s) buy the most current scan tool and then learn how to read it using the correct service manual per app.

715517

I've been thinking of buying a proper scan tool for it but i live in northern europe so there is no change to have it all the way here before winter. And the boat is going to merc workshop(they have a scan tool) next week but i try to fix it myself before it.