V6 mpi mercruiser not advancing timing

[Waterloo3]

Sn owo41676 jul 2004 v6 mpi the motor is not advancing timing as it should at idle it is sitting smack on top dead 0 deg and is only advancing at set points in the rev range. Timing was checked with a digital timing light ,balancer has not slipped. With light on timing marks they do not dance around as it should trying to find optimal timing. Boat will run the same with knock sensor disconnected or connected it is a new censor . I have tried the knock test on block with hammer and it does not pull timing. Motor has been this way as long as we have owned it. Ignition has been given a complete overhaul as has the fuel. Distributor is set as per manual on the 6 mark all timing marks have been checked and re checked I know timing is non adjustable. Is there any fail safe in the ecm that would revert to a safe timing curve with out guardian mode going of ? Boat starts well it has a slight flat spot on hard acceleration and is lacking a bit of hp but overall it does what it needs to we only ski and wakeboard so the flat spot is annoying. Getting to a dealer is difficult but not impossible but they don’t work on I/o so are not interested in sea trials or fault finding. I can get it on their scanner if I have something to check. thanks in advance

 

[Rick Stephens]

Two things can cause that:

1: the two white base timing mode leads are shorted together.
2: the ThunderboltV module is bad.

 

[achris]

Hello Waterloo3, and :welcome: to iboats.

This is an MPI engine... You need to get the Diacom software on it and see what's happening while the engine is running. Without the software, my guess would be (and this is just that, a WAG!) check the IAC... Beyond that, the software should be your first checkpoint...

If the only dealer around doesn't want to help you, you are going to need to purchase the software yourself, and learn how to use and interpret it... But remember, and this is the critical part. The software is just one of your tools, it's not the ONLY tool, and if it reports nothing, you keep looking. If the software is reporting nothing it's just telling you where you don't need to look.

tpenfield also uses the same software as I do, and he'll also tell you just how important it is as a tool for working on MPI engines.

Chris..........

 

[Waterloo3]

Chris would the Rinda techmate be good enough or do I need the Diacom. Is there any were in Australia to send ecm for checking repair? iac has been replaced. Boat runs, idle’s fine but has a flat spot on hard acceleration and is swing a 19 pitch prop and only just getting wot at 42 km the boat is a regal 17.6 foot bow rider. Thanks for the welcome and the advice Scott

 

[achris]

Scott, where are you in Oz?

Techmate is really only a code reader. It can't give realtime values. I feel your problem will need to reference live data, not codes.

Chris...

 

[Waterloo3]

Chris I’m in se South Australia. I just made the mistake of mentioning spending more money on the boat and it went down like a lead balloon. So it looks like we will be putting up with it “as apparently there is nothing wrong with it “so it’s back to sitting in the boat with a beer looking at the motor with a frustrated look on my face thinking what to try next. Thanks Scott

 

[achris]

Mt Gambier area....?

As for ECM repairs in Australia, I doubt it, I haven't heard of any, and the market's just too small...

Next opportunity I have, I'll pull my boat out and run it up and do a video so you can see the timing... Not sure when that'll be though... But, it sounds like you're not going far...

Cheers,

from Perth.

 

[tpenfield]

Just to add what Chris had said . . . We have seen quite a few threads this year about problems with MPI engines. All to often traditional trouble-shooting methods are used to no avail and lots of money gets wasted on replacement parts that were not needed.

Codes readers are one thing, but not everything, so you may not be able to fix things with just a code reader.

All too often I see folks willing to throw $500+ in unnecessary parts at an MPI engine problem, where they would have been better off putting the $500 towards the software. It pays for itself by the first or second time you have to use it.

 

[Waterloo3]

Yes that’s right about 70 km away . Thanks Chris that would be good . Yes water is to cold for water sports just yet anyway. So unless you’re going to get Diacom the techmate is not a lot more use then smartcraft?

 

[Waterloo3]

Update I have software and have scan with no faults present. The ecu thinks the timing is running correctly at around 8 deg but with timing light it is around 0 or even slightly less my light will not go past 0 . The marks are correct I have checked at top dead (heads were off) so I presume it is a issue with sensor/trigger some how not being correct.

 

[QBhoy]

Hi. As you will likely be aware. These mpi engines can be a chain reaction of faults triggered by just one fault. Often giving symptoms of other faults by them trying to compensate for another fault.
First thing I would ask is if the Diz has been changed ? If it hasn’t or even has. Do it again and see what happens. I’ve been through 4 in 3 1/2 years now. With one failing after only 2 weeks.
Other well known issues are the IAC (but you ruled out), throttle position sensor and SW pressure switch. Most of them would alarm, but the diz cap failure can throw all sorts of issues and symptoms at you. Been through them all but most notably the diz cap.
My most recent issue was the shift interruption switch being faulty and momentarily cutting the rpm at different throttle positions. Mostly WOT.

 

[Waterloo3]

Distributor has been checked and swapped and then swapped back again. It is not the problem. If you are burning distributor caps out that quickly moisture must be intruding from somewhere or caps are of low quality. Thanks for your feed back but I have checked all you have suggested plus some, I even bought diacom software no codes that would be a issue. I would like to close post thanks

 

[achris]

Is the Diacom software indicating that the timing is advancing?

 

[Waterloo3]

Hi Chris yes it is, base timing is off diacom is showing 8 deg btc,lights ( I tried more than one )are showing around 0 deg. Timing mark is correct. What I have found it the timing cover is Chinese and the sensor hole looks like it is slightly off when compared to a Gm cover I might be clutching at straws. But I cannot think of any other reason why it is triggering so late. I’m going to order new one today and cross my fingers.

 

[achris]

Back when I was having oil leak problems (long story), I did put one of those Chinese covers on. Terrible pieces of rubbish. A quality cover isn't expensive, about $40, unless you live in Australia, where the Merc dealers want to charge over $200...

 

[QBhoy]

Hi. Really interested in how you get on with this. Have you had the boat out for a run ? How does it perform ?
You think it might be running advanced as in like it would when cold ? Just trying to get my head round what’s happening. Did you discover this because you were having an issue with it running ?

 

[achris]

Here's a link to the original leak problems (get yourself a jug of coffee, it's a long read)... http://forums.iboats.com/showthread.php?t=373060

I've been using the boat for about 5 years now without a problem. I have the Diacom software and it's reporting the timing advancing as it should. I have had a timing light on it, and at idle, when the software says 8 before, the marks agree.

I used the chinese cover (just the once!) because,at the time, it was the cheapest (and quickest) option. I tossed it pretty much straight away and just waited the 3 weeks for one to come from a GM parts supplier in the U.S.

Chris.....

 

[Waterloo3]

I ordered a mercruiser timing cover today I’m to inpatient to wait three weeks I just hope it fix’s the problem. Funny when I ordered it I was asked if the old one had cracked.

 

[achris]

Yeah, it's quite a well documented problem. Occurring in MerCruiser and Volvo marine engines, and a lot of GM cars and trucks. All later 2005 and 2006 engines. Not all engines, so I believe they had a problem with one of the moulds, which they found at some time in 2006. But too later for a lot of engines that got through. Neither GM nor Mercury have ever acknowledged their responsibility. And this puppy is none too happy about that...

 

[Waterloo3]

Hi just a follow up on the timing issue . Replaced the ecm with another problem fixed. Thanks for all the replies.