4Lance

I really dont think its fuel psi

4Lance

Just running rinda software a bunch of things come up under flash memory errors one said knock sensor 1

4Lance

Watch "2003 496 ho surging? Help" on YouTube
2003 496 ho surging? Help: http://youtu.be/aSALjGAD3Vw
Watch "2003 496 ho surging? Help" on YouTube 2003 496 ho surging? Help: [url]http://youtu.be/aSALjGAD3Vw[/url] Does it at 36 seconds

Expensive Date

That beep and drop is you losing ignition.you have a bad connection or broken wire in your injector harness engine running on hose wiggle and pull on every wire till you duplicate.

4Lance

Every wire to injectors? Or to coil packs? I wondered if maybe they laid on top plastic engine cover or took it off and hurt something

4Lance

I thought it seemed electronical but I took dash apart and cleaned all harnesses some had a little green used elec cleaner then wd40 wiggled all them and didnt do it went back to main engine round plug did the same and wiggled still never did it

But then I thought sensor bc it only dpes it when it gets hot I have to let it run like 15-20 min somtimes for it to do it.

Whats weird is I changed iac valve put on river started up idled out of marine 5min then got on it decent got on plance cruised 10min went back down to idle and a couple min later it starts surging only did it once that friday night. Next morning started it and it started doing it within 5min of idle and in gear took off on plane was running great then back to idle to pull up to beach and it did it like every minute. ..

Expensive Date

That beep you hear is the same beep you get when you first turn the key on before you start engine. You are losing ignition and the ECM thinks engine is off. I had the same exact thing on my old boat once with 6.2s. Start at the front of the engine while running and work your way back, because it only does it when hot it may even be a lose ground wire, mine was in the injector harness. It was wierd though once I found it, pulled back the tape could not find a break and then it did not do it again for a year. I eventually had to change the harness.

4Lance

Ok thank you makes me feel better knowing somewhere else to look

Sydwayz

iTrader: (1)

I tend to agree with Tim (E.D).
Once John (BUP) sees this, he will also chime in.

Once things get hot, resistance goes up as conductivity goes down. If you have a damaged wire, it starts to fail when hot.

BUP

iTrader: (9)

I just got my Techmate pro as well but have not had a chance to even open it up. Go to PCM faults and then Read Faults. However you can report them back here word for word do so exactly. After you play with the scan tool to see how it works do a fuel injector output test and you can even do a ignition coil output test.

To give you a little info as it should be your user guide manual from Diacom / Rinda. The fuel injector output test will let you know that each Fuel injector is receiving the signal from the PCM. It will not be able to tell u or test for a dirty / restricted injector(s). You need to disable the fuel pump for the test beforehand..

Also another good test to do is an injector balance test. Hopefully you can google it how to perform or buy the service manual Mercruiser PCM # 33 you will need to get the 2007 version of this manual, it is better than the 2001 version. Has more depth.

I would make sure you do not have a vacuum leak at the IAC or the hose and buy a new IAC Muffler, It can tame some surging..

What did I need to see ? sorry I didn't read every post.