Jim

I have a "fuel pressure" problem on a 1999 Cherokee limited 4.0.
The pressure leaks away after the vehicle is turned off.
Can this be something other than the fuel pump????
Any thoughts/opinions would be appreciated!!

Thank-you

Jim

Rich Pierson

There is a check valve on the fuel pump, however befor jumping on that I
would open the hood and look in the engine compartment and underneath to
make sure fuel is not leaking out somewhere else first. To replace the fuel
pump you need to drop the tank. A suggestion, if you do it yourself mark
where the pump is in relation to your rear floor then while the tank is out
cut a 5 or 6 inch hole under the carpet, use some sheetmetal and screws and
some rubber gasket material to make a new cover, por-15 the cut area to
prevent rusting. That will ensure you don't have to drop the tank again to
change it out. My ex-brother in laws dodge daytona had an access hole in
the trunk for this. Do not use an aftermarket fuel pump either, they seem
to have a high failure rate.

piglet80917@netscape.net (Jim) wrote in news:bbb8ca7e.0309150659.135d8e01
@posting.google.com:

> I have a "fuel pressure" problem on a 1999 Cherokee limited 4.0.
> The pressure leaks away after the vehicle is turned off.
> Can this be something other than the fuel pump????
> Any thoughts/opinions would be appreciated!!
>
> Thank-you
>
> Jim
>

Rich Pierson

There is a check valve on the fuel pump, however befor jumping on that I
would open the hood and look in the engine compartment and underneath to
make sure fuel is not leaking out somewhere else first. To replace the fuel
pump you need to drop the tank. A suggestion, if you do it yourself mark
where the pump is in relation to your rear floor then while the tank is out
cut a 5 or 6 inch hole under the carpet, use some sheetmetal and screws and
some rubber gasket material to make a new cover, por-15 the cut area to
prevent rusting. That will ensure you don't have to drop the tank again to
change it out. My ex-brother in laws dodge daytona had an access hole in
the trunk for this. Do not use an aftermarket fuel pump either, they seem
to have a high failure rate.

piglet80917@netscape.net (Jim) wrote in news:bbb8ca7e.0309150659.135d8e01
@posting.google.com:

> I have a "fuel pressure" problem on a 1999 Cherokee limited 4.0.
> The pressure leaks away after the vehicle is turned off.
> Can this be something other than the fuel pump????
> Any thoughts/opinions would be appreciated!!
>
> Thank-you
>
> Jim
>

Will Honea

On Mon, 15 Sep 2003 14:59:48 UTC piglet80917@netscape.net (Jim) wrote:

> I have a "fuel pressure" problem on a 1999 Cherokee limited 4.0.
> The pressure leaks away after the vehicle is turned off.
> Can this be something other than the fuel pump????
> Any thoughts/opinions would be appreciated!!

The leak-down limit is something like 10PSI in 10 minutes. I think
yours still has the separate return fuel line with the pressure
regulator on the fuel rail. If so, it could be a leak in the
regulator. With the key off, pinch the return line (visegrips, clamp,
etc.) turn the key on and back off - just long enough to get pressure
on the system. If it still leaks down it's either the pump, a leaking
connection, or an internal leak in an injector. Only way to isolate
it futjer would be to pull the input line to the fuel rail and see if
the bare line leaks down but that takes some fiddling with fittings
and such. You might be able to run a good injector cleaner thru the
system and see if that helps any - note the rate of the leakdown
before and after the cleaner. That's a whole lot cheaper anf easier
that a new pump.

--
Will Honea <whonea@codenet.net>

Will Honea

On Mon, 15 Sep 2003 14:59:48 UTC piglet80917@netscape.net (Jim) wrote:

> I have a "fuel pressure" problem on a 1999 Cherokee limited 4.0.
> The pressure leaks away after the vehicle is turned off.
> Can this be something other than the fuel pump????
> Any thoughts/opinions would be appreciated!!

The leak-down limit is something like 10PSI in 10 minutes. I think
yours still has the separate return fuel line with the pressure
regulator on the fuel rail. If so, it could be a leak in the
regulator. With the key off, pinch the return line (visegrips, clamp,
etc.) turn the key on and back off - just long enough to get pressure
on the system. If it still leaks down it's either the pump, a leaking
connection, or an internal leak in an injector. Only way to isolate
it futjer would be to pull the input line to the fuel rail and see if
the bare line leaks down but that takes some fiddling with fittings
and such. You might be able to run a good injector cleaner thru the
system and see if that helps any - note the rate of the leakdown
before and after the cleaner. That's a whole lot cheaper anf easier
that a new pump.

--
Will Honea <whonea@codenet.net>