Re: Spark Knock Update

From: mrdancer (mrdancer@camalott.com)
Date: Thu Oct 07 1999 - 12:20:28 EDT


Erica, sounds like you're having some nagging problems with your Dak. If
worse comes to worse, you can always drop a 360 crate motor in there :)

Anyway, following are some posts I made to the DML several months ago, maybe
they will help you out. The first one appeared in MoPar Performance News
about five or six years ago, I thought they were referring mainly to early
Magnums, but maybe they haven't fixed the problem yet??

HTH

'92 Dak CC 2wd 318 3.55
'84 GoldWing Interstate
=============================================================

SOURCE: MoPar Performance News, Tech Tips, by Larry Shepard - Mopar Chief
Engineer

The problem is related to the gasket that seals the cover to the bottom of
the manifold on the Magnum engines. If this gasket does not seal properly,
the engine can suck in oil vapors from the lifter valley and cause the
engine to detonate due to the aggressive spark advance curve used in the
Magnum computers. Remembering where this gasket is located, this is not
the first thing that you want to do. It could be expensive and time
consuming
to pull off the intake to check. However, we have a helpful tip. To
determine if there is a proper seal, remove the PCV (Positive Crankcase
Ventilation) valve from the right hand valve cover, but leave the PCV valve
attached to the hose from the intake manifold. Remove the breather hose
from the left-hand valve cover that goes to the air cleaner. Plug-off the
connection at the valve cover. With the engine idling, place your thumb
over the opening where the PCV valve was located. After 10-15 seconds you
should feel pressure, which indicates that the gasket is sealing. If you
feel a vacuum, the gasket is leaking and needs to be repaired. The best
repair is to remove the intake manifold, remove the bottom plate and
discard the failed or leaking gasket. Clean all the surfaces thoroughly,
and apply
a bead of Mopar RTV sealant, PN 82300235 to the bottom of the manifold.
Re-install the plate, let dry and then re-install the manifold. Refer to
the service manual for manifold installation tips and details.

=============================================================
Also, from the "alt.autos.dodge.trucks" newsgroup.......

In hopes this will help all with the pinging problem they are experiencing.
Chryco TSB #18-24-98 covers 96-97 Vans, Dak's, Ram's, Cherokee's and Grand
Cherokee's with 2.5L, 4.0L, 3.9L 5.2L & 5.9L engines. This TSB announces a
new software revision that allow the dealer to tweak the timing slightly to
mitigate the engine ping condition. Also, Chryco TSB #18-48-98 covers '94 -
'99 Dak's & Ram's, '94 - '98 Grand Cherokee's and '98 & '99 Durango's, all
with 5.2L & 5.9L engines. It identifies a possible crossfire problem with
the plug wires and offers new P/N's for isolators and convolute insulation
that will mitigate this problem also. Contact your dealer for more info on
these fixes. Hope this helps... Good Luck!!
Chryco Service Manager
Member SAE
Mike Simmons wrote in message <36ccd713.0@news.fidnet.com>...
>To add yet another thread to this seemingly endless discussion, I forthwith
>will throw my two cents worth in!
>I was unable to determine what model year 5.2L/5.9L engines we are dealing
>with, however Chryco just released a TSB that offers a software update that
>allows the dealer to "tweak" the timing slightly to alleviate abnormal
>engine ping. This TSB does not apply to all model years, so let me know
>what year and I will check for you or check with your dealer. Also, I have
>found that an excess carbon buildup in the combustion chamber can be the
>cause of a lot of abnormal engine ping. It seems that the carbon deposits
>retain heat from the power stroke (ugly Ford word!) and incandesce and
allow
>preignition of the air/fuel mixture. A good commercial combustion chamber
>cleaner, or in severe cases sand blasting the chamber with walnut shells
>thru the spark plug holes has fixed many of these cases. Good Luck!
>
>Chryco Service Manager
>SAE Member
>



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