Re: Pinging Solved... at least for my truck. Long now...

From: Clay Cooke (cooke@ecn.purdue.edu)
Date: Tue Jan 18 2000 - 14:50:49 EST


The Dodge SMFI on all the 5.2 and 5.9 Magnum motors uses a "speed density"
system, it doesnt use a MAS (mass airflow sensor), it uses a MAP (Manifold
absoute pressure) sensor (the black box on the front of the TB, a IAT
sensor (incoming air temp sensor), and the O2 sensor to calculate the fuel
ratio...

Clay

84 Dodge Ram, scrappin pavement w/ 440 8bbl
96 Indy Ram, scrappin EVERYTHING w/ 360 Magnum!' -(www.indyram.org)
69 Road Runner 440 6bbl, project car

http://expert.cc.purdue.edu/~cooke

On Tue, 18 Jan 2000, David Monk wrote:

> Either they have an air mass sensor... which I think they do, or my
> explanation works all the better. You have to have some type of calibration
> for how much fuel to inject at any given point in time This maintains the 14
> to 1 or whatever ratio for proper combustion. Most companies use an air
> mass flow sensor or air venturi mounted in the intake path. The signal from
> which is sent to the computer, which takes into account for temperature,
> elevation, etc, to tell the injectors when and how much fuel to dispense.
>
> If we don't have an air mass sensor, then the computer runs "blindly"
> according to a set volume of air that *should* be getting into each
> cylinder. This would leave all the more room to screw up and run lean or
> rich as the case may be.
>
> Anyway, I believe the directly ported FI Dakotas, and probably the throttle
> body FI ones too, have an air mass sensor mounted at the very base of the
> throttle body, just above the intake manifold. It is a white plug (at least
> on my 98) mounted to a squarish box thingy, if I remember correctly.
> Probably the reason that DC can't seem to fix the problem is because they
> can't go around telling everyone to ditch the stock air intake and slap on a
> 35 dollar K&N. Instead, they just make comments like "Its supposed to
> happen" Yeah, right.
>
> I may be wrong, but honestly, it worked for me, and it is cheap to try. At
> the very least, I guarantee better air flow.
>
> Dave
>
> ----Original Message Follows----
> From: "Bernd D. Ratsch" <bernd@texas.net>
> Reply-To: dakota-truck@buffnet.net
> To: dakota-truck@buffnet.net
> Subject: Re: DML: Pinging Solved... at least for my truck.
> Date: Tue, 18 Jan 2000 12:04:23 -0600
>
>
> Sounds good. Uhhh...our trucks don't have a mass airflow sensor.
>
> - Bernd
>
>
> At 12:52 PM 01/18/2000 -0500, you wrote:
> >My truck used to ping. 1998 Extended Cab, 3.9l V6, 5 speed (Let me know
> >if anyone wants more info). I noticed that the problem got worse when I
> >put a 3" lift kit on my truck. It actually got to the point that I could
> >feel the engine "jerk" when I drove up a hill on interstate 71 in fifth,
> >while lugging the engine. I started running 89 octane, which made the
> >pinging go away somewhat. I then dedided to replace the spark
> >plugs. When I pulled the old ones out, I noticed that they had very long
> >electrodes. Something like a half an inch. I felt that they were way too
> >hot, so I replaced them with colder plugs. The pinging got a little bit
> >better, but it was still there. So, I decided start playing with the air
> >intake. The flexible tube had gotten a little kinked as a result of the
> >lift, so I looked into getting a K&N intake setup. Since they don't (or
> >didn't) make one for a 98 V6, and since the air mass sensor is located in
> >the throttle body, I decided to just rip off the whole air system from the
> >flexible tube back. I bought a K&N canister filter (PN RU2820) with a 3.5
> >inch diameter whole, 6 inches long, and about 5 inches in diameter. I
> >clamped it directly to the intake housing. The pinging is gone. I can
> >take the same hill that I used to ping like crazy on, and floor it in
> >fifth gear and get *no* pinging. Looking back, I feel that what was
> >happening was too little air was being taken into the cylinder, therefore,
> >too little gas was injected. This leads to a lean charge in the cylinder,
> >which in turn is easier to ignite (via too hot a spark plug). I may be
> >crazy, but it worked for me... total cost... 6 1.29 dollar spark plugs
> >(Bosch, forget the Chumpion crappy ones) and a 35 dollar K&N cannister
> >filter. Not too shabby.
> >
> >Dave
> >______________________________________________________
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>
>
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