On Apr 14, 1:55=A0pm, Mike Romain <roma...@[EMAIL PROTECTED]
> wrote:
> sls5...@[EMAIL PROTECTED]
wrote:
> > On Apr 14, 12:13 pm, "Mike" <m...@[EMAIL PROTECTED]
> wrote:
> >> <sls5...@[EMAIL PROTECTED]
> wrote in message
>
>
>>news:2a905b5d-e2ab-4848-bd6a-4c2f4d0962c7@[EMAIL PROTECTED]
>
> >>> I have a 93 grand cherokee with 200Kmiles. It idles smoothly and
runs
> >>> ok but I cannot hold a steady rpm over 1000 RPM.It surges slightly
> >>> over a 300 RPM range. I've replaced cap, rotor, wires, coil, and
> >>> plugs. I've checked all the vaccum hoses for leaks. I even went as
far=
> >>> as to plug all the vacuun ****ts in the manifold and throttle body.
It
> >>> still surged slightly.
> >>> I removed the throttle body and cleaned it thoroughly, replaced the
> >>> TBI gasket. I've used seafoam in the gas tank (it ran really crappy
> >>> until I filled up again). Cylinder compression is good considering
> >>> it's age (around 150psi max, 130 min).
> >>> Fuel economy is less then I expect. In a relatively hilly area I get
> >>> around 11MPG in mixed (mostly city) driving. Overall drievability is
> >>> pretty good and power is good all the way to redline. This leads me
to=
> >>> believe I have enough fuel pressure.
> >>> Any ideas?
> >>> Thanks in advance!
> >>> sls
> >> =A0 Surging is usually a sign of running lean. I would check the
operat=
ion of
> >> the O2 sensor(s) with a scan tool to make sure they are working
properl=
y. To
> >> do so you would need a scan tool that is capble of reading sensor
value=
s. =A0You
> >> can also check O2 performance with a multimeter. It may be cheaper
just=
to
> >> replace the O2 sensors from the start due to the high mileage on the
ve=
hicle.
>
> >> =A0 =A0I would check the fuel pressure as well just to rule that out
as=
a
> >> possibility. The fuel pressure regulator increases fuel pressure
under =
power
> >> conditions so it could still be low at cruise.
>
> >> =A0 What engine do you have ? =A0If you have a V8 they have a pan on
th=
e bottom of
> >> the intake that is prone to leaking, the only way to check it is to
rem=
ove the
> >> intake.
>
> >> =A0 Also check your EGR valve for proper operation. =A0If it opens
too =
far or at
> >> the wrong time that may cause a surge also.- Hide quoted text -
>
> >> - Show quoted text -
>
> > One more thing i didn't make clear in my original post. It's a cycling
> > surge. If I hold the throttle steady as if I was trying to hit
> > 1500rpm, the engine will cycle from 1300 to 1600 RPM. Each cycle (up-
> > down-up) is about a second long. It does NOT do this at idle. RPM is a
> > steady 700 or so. Pretty much anythin above 1000 RPM will do the 300
> > rpm cycle.
>
> > Interestingly enough, I replaced the throttle position sensor a few
> > months ago. When I first started the vehicle, it idled at 1500 RPM. It
> > did the same 300RPM cycle even though the throttle was closed. Of
> > course after the computer "got used to" the new TPS it idled normally.
> > It definitely appears to be RPM dependent.
>
> > Thanks!
> > sls
>
> Usually the problem with the TPS is a bad connection, not a bad TPS.
> You only fixed half the problem with the new TPS. =A0I would get some
> electronic spray contact cleaner and do out the plug and socket for the
> TPS first. =A0The told us our TPS was dead in 1999, it was
>
> The other sensor's connections can also benefit from this clean. =A0I
use
> dielectric grease on the plug's sealing skirt to help keep them clean.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 'New' frame in the works for '08. =A0Some Canadian Bush Trip and Build
> Photos:http://mikeromainjeeptrips.shutterfly.com-
Hide quoted text -
>
> - Show quoted text -
Thanks for the feedback.
The problem occured before I changed the TPS (one of the parts I threw
at the problem)
I actually did clean all the sensor connectors with radioshack contact
cleaner (IAC, TPS, MAP) I also cleaned the washer and coolant
reservoir sensors but they still show up bad at the most embarassing
times on the VIC. :-)
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