MICHAEL CABE <mikecabe@prodigy.net> wrote:
> Mike,
> I replaced the whole stock air box with the K&N setup . It just
> seems that it is dogie and falls on its face like a lean condition .
> I see no gas mileage gain . I put new plugs in at the same time as
> they were shot . I used champion iridium plugs .
You changed 2 variables at once, so its not possible to blame the
K&N without first eliminating it or the plugs from the equation. The
FSM says that the 4.7L is equipped with copper core plugs from the
factory and warns that preignition will result if another type of plug
is used. I'm not familiar with the Iridium plugs, but they could very
well be the cause of your problems. Frankly, the fancy spark plugs
usually cause more trouble than they are worth, and that might be the
case in your situation. Its a bit of a hassle to swap plugs, but one
thing you could try is to put the stock intake system back on, and if
the truck wakes back up, that could be an indication that the problem
is indeed the K&N. If not, it might be the plugs. Did you gap them
to .040"?
> The truck has about
> 62000 on it .It idles smooth as silk and cruises fine . I think it
> sucks too much air .
With an EFI system, it isn't really possible to suck too much air
- the engine will only use as much air as it needs, regardless of the
flow capability of its intake tract. Unless you're using some sort of
forced induction, I would not expect the engine to lean out simply
because the intake has more flow capability.
> I have had the K&N setup on it for about 3000
> miles I would think it would have learned by now .
Probably, but if you did not disconnect the battery during the K&N
install, I'd recommend doing it now, just to make sure the computer is
starting out from scratch.
> The truck has no
> mass airflow sensor or an air temp sensor .
Unless you have modified the engine from stock, the air temp
sensor is located in the intake manifold, near the left side of the
throttle body.
> After I installed the
> fipk i read an article some where I don't remember where that said
> without a mass airflow the computer doesn't know what to do with the
> xtra air and could create a lean condition .I just wanted to know if
> anyone had heard this or had the same problem Mike Cabe
No, a mass airflow sensor is not necessary - our engines use the
speed density system which uses a manifold pressure sensor and engine
RPM as inputs to a lookup table to calculate fuel requirements. The
oxygen sensor compensates from there (within certain limits) to keep
the air/fuel ratio right. A K&N intake is well within the operating
parameters of the stock programming and will not lean it out.
Also, you mentioned that the truck feels "dogie" and falls on its
face. I assume this is during hard acceleration? Under those
conditions, the truck is in open loop and the stock fuel mapping is so
rich that there's no way a K&N intake could lean it out to that
degree.
It sounds like there is something else going on here. Possibly a
sensor which wasn't plugged back in or got knocked loose during the
install. My gut is telling me to suspect those spark plugs. Since
swapping the intake out is really easy, my recommendation would be to
slap the stock intake back in there and see if the truck goes back to
normal. If not, I'd yank those plugs and install a set of the
recommended copper core plugs. (Champion RC12MCC4, or possibly the
Champion 4071 truck plugs)
--
-Jon-
.- Jon Steiger -- jon@dakota-truck.net or jon@jonsteiger.com -.
| '96 Kolb Firefly, '96 Suzuki Intruder, Miscellaneous Mopars |
`-------------------------------- http://www.jonsteiger.com --'
This archive was generated by hypermail 2b29 : Mon Nov 01 2010 - 10:47:31 EDT