accelaration problem ..exhaust

[laurie88]

400hrs 206 used in salt permananent, replaced exhaust maniflod and now get engine mis/ pop at 1700rpm every time....sound like something is blocked
we have done lots of research and just waiting for diagnostic tool

no engine warn light , all gauges ok, starts first time,idles fine, changed all plugs, distr cap, rotor, leads, filters, pumps , oil press sensor, ect, etc, fuel pres ok

we are now thinking the mechanic could have done something related the the exhaust, since the sympton only started after the change of manifolds
has anybody experienced this sympton of popping/ misfire under load maybe with damaged muffler, baffles, something broken in exhaust etc..is it common

tx

[Quinner]

Been following your many threads as I am very curious as to what exactly will fix your issue(s).

You may want to post your problem & description on www.correctcraftfan.com as well.

Good Luck

[Mikeski]

what do the plugs look like?

popping or backfiring is typically caused by a lean condition. it could be as simple as a cracked hose in a vacuum circuit (if there is one on your boat). My guess is that something got bumped or broken during the replacement, but that's just a guess and it's not great to do guesswork on these.

The repeatability at 1700RPMs is the most telltale of your description. You need to determine what happens at 1700 rpms, does a channel in the FI open, does a vacuum switch open, does the timing change?

Assuming it doesn't do it unloaded starts to point me towards a full throttle circuit in the FI. Maybe a coincidentally failing injector, guessing again...

[laurie88]

plugs look ok

whats the F1

Where is the vacuum circiut.....up to now cant see any damaged hoses

boat is model 206 yr 2007

tx

[horkn]

"F1" is actually FI, or fuel injection....

Shouldn't that boat be under warranty?

[Andy3535]

This might help

This Product Information Update supercedes SUP2006-04, Information on Setting CAM Retard PCM 5.0L (Pro Ski) and 5.7L
(Excalibur) engines, serial number range 470001 through 485993.
When rotating the distributor on the affected engine, you are adjusting what is called “CAM Retard.” This parameter
represents the position of the distributor rotor relative to the proper terminal in the distributor cap when the spark is delivered. The
specifi cation indicated for this engine is 0-4 degrees. If the engine is set at 0 degrees, under certain precise RPM, temperature
and load conditions, the engine can “crossfi re.” This means the spark jumps to the wrong terminal within the distributor. This can
cause a slight backfi re or sputtering under this condition. To ensure this condition does not exist, CAM Retard should be set
between 6-8 degrees on engines between serial numbers 470001-485993.
This is a correction made to the tune-up specifi cations and should be checked and set to specifi cation during normal service
intervals. In most cases, the problem does not exist. This is not an update that requires you to have the customer bring the boat
in specifi cally for this update, it can be simply done during normal tune-up and/or commissioning procedures. A new specifi cation
decal needs to be installed after the adjustment is made. Contact PCM in order to receive updated specifi cation decals, p/n
R143170B-U, which indicates the correct CAM Retard specifi cation.
NOTE: Engines built starting with serial number 485994 have been changed to a new specifi cation (15 +/- 2 Degrees) and circuit
diagnostics added. These engines DO NOT need to be changed.
In order to properly set the CAM retard, the following scan tool MUST be used:
PC Based Diagnostic Software: Diacom Diagnostic Software, Marine Edition, by Rinda Technologies, Inc.
Available for purchase through PCM, P/N RT0086.
1. Connect the laptop to the engine’s data link connector.
2. Per the tool instructions, navigate the tool to view ECM data.
3. Find the engine parameter labeled “CAM Retard.”
4. Engine must be running in order to view the CAM Retard value.
5. CAM Retard value MUST be set between 6-8 degrees. If the value is within specifi cations, make sure the distributor hold
down bolt is tight.
6. If the value is outside the specifi cations, loosen the distributor hold down bolt and slowly rotate the distributor until a value of
6-8 degrees is achieved. Tighten the hold down bolt securely, making sure the CAM Retard value does not go outside of the
specifi cation. Once the distributor hold down is tightened, verify the value still remains between 6-8 degrees.
Important: The basic principle that the distributor must be installed into the engine properly still exists. If the proper CAM Retard
cannot be achieved, check the installation of the distributor.
7. Clean the surface of the old specifi cation decal and install new specifi cation decal, p/n R143170B-U.
Engines Affected: 2007-2008 5.0L MPI (Pro Sport) ALL 2007-2008 5.7L MPI (Excalibur) ALL S/N: 470001-4859

[Quinner]

Might be worth spending a few minutes double checking no plug wires were crossed when they were re-installed.

Check the firing order.

[laurie88]

Thanks Andy

put the diacom on last night eventually

cam retard was -10.5??. degrees........no fault codes

presume -10.5 is not right

how can it slip....how to fix???(new distr maybe)

my o& m manual says master engine spec 0-4 degrees, as you update suggests, and tune up spec 43-47 degrees.??...dont understand this?

[scuff97]

you will have to hook up Diacom and with the engine running at idle turn the disributor until you reach 6-7 degrees. that should take care of the popping back and engine miss

[laurie88]

you will have to hook up Diacom and with the engine running at idle turn the disributor until you reach 6-7 degrees. that should take care of the popping back and engine miss

thanks guys

i will try this on saturday with the diacom, fingers crossed

[slob02]

I did have a "baffle" break in my 1997 muffler and basically blocked the exhaust from getting out completely. Eventually the pressure was to much and cracked a hole in the muffler.

[laurie88]

fixed the prob at last, connected diacom and turned distributor until cam retard was at 7 degrees

[Quinner]

Good news! Curious where you are located that there is no dealer nearby?

[Andy3535]

Good news! Curious where you are located that there is no dealer nearby?

Great that you found the fault!

What I do not understand is why it needs a English man living in Germany to give you guys a tip on where to set your cam retard!!!!
This service update from PCM I found searching the internet!
Andy

[DanielC]

This is a note to PN administrators.
Threads like this one should have a special place, or pinned to always stay on the top of lists. Setting the distributor is one of those basic things, like checking the fuel pressure, that when random engine problems show up, you need to be aware of.
Maybe a category subdivided in to GT-40 engines, Apex engines, Excalibur engines, Python engines, ETC.