Re: new version of mpi kit
 

Approximately 8/13/03 15:18, DougW uttered for posterity:

> Lon Stowell wrote:
>> Approximately 8/13/03 04:27, DougW uttered for posterity:
>>
>>> Will Honea wrote:
>>>> On Tue, 12 Aug 2003 21:45:24 UTC "DougW" wrote:
>>>>
>>>>> Jeff Strickland wrote:
>>>>>> No return line, how does that work?
>>>>>
>>>>> My guess would be "poorly" :)
>>>>>
>>>>>> "serg" wrote ...
>>>>>>> yup! no return line...i'll let you guys know for sure when my kit
>>>>>>> arrives...
>>>>
>>>> No crap! It's enough of a pain to bleed the air out of an empty
>>>> line/rail with the bypass flow of the external regulator so just
>>>> imagine the PITA this will be if you ever happen to run out of gas.
>>>
>>> Actually don't think I've ever seen a fuel injection without a return
>>> line. That's the only way to keep regulated pressure in the rail.
>>> I'm betting there is a return line but it's just not shown. Guess we all
>>> will find out when your kit gets in.
>>>
>>
>> Take a look at a Factory Service Manuual for the ZJ series.
>> No return line. The regulator is in the fuel pump which is
>> in the gas tank. You have to release pressure at the fuel
>> rail to do much of anything.
>
> Must be the later ZJs, mine has a return line, that's how it sets
> the rail pressure. Back port is fuel-in, front is the return line
> routed through the stock regulator then the Edelbrock regulator.
>
> http://members.cox.net/wilsond/regulator-detail.jpg

1995 to be precise, all engines. Goes into great detail
on the regulator being in the fuel pump, and for both the
4.0 and 5.2 engine removal of the fuel rail itself requires
detaching only the fuel supply line, no return. Even a
recall against some fuel pumps which may have been fitted
as replacements supplying a bit too much pressure since
the regulator is no longer used as of the 1995 year on
either engine. Have no idea on older or later ZJ's.

Re: new version of mpi kit
 

Lon Stowell wrote:
> Approximately 8/13/03 15:18, DougW uttered for posterity:
>
>> Lon Stowell wrote:
>>> Approximately 8/13/03 04:27, DougW uttered for posterity:

<snippies>

>>> Take a look at a Factory Service Manuual for the ZJ series.
>>> No return line. The regulator is in the fuel pump which is
>>> in the gas tank. You have to release pressure at the fuel
>>> rail to do much of anything.
>>
>> Must be the later ZJs, mine has a return line, that's how it sets
>> the rail pressure. Back port is fuel-in, front is the return line
>> routed through the stock regulator then the Edelbrock regulator.
>>
>> http://members.cox.net/wilsond/regulator-detail.jpg
>
> 1995 to be precise, all engines. Goes into great detail
> on the regulator being in the fuel pump, and for both the
> 4.0 and 5.2 engine removal of the fuel rail itself requires
> detaching only the fuel supply line, no return. Even a
> recall against some fuel pumps which may have been fitted
> as replacements supplying a bit too much pressure since
> the regulator is no longer used as of the 1995 year on
> either engine. Have no idea on older or later ZJ's.

That makes sense. I know they made some significant changes starting
in 95. I guess they think any air will pass through the injectors.
That would make increasing fuel flow/pressure a real pain in the ass
without having to splice in a secondary fuel pump.

Oddly I did read about a 2003 vane type charger for the 4.0 that has
a return line you put into the fuel fill tube. I was wondering
why the seperate return line and that explains it.

--
DougW

Re: new version of mpi kit
 

On Wed, 13 Aug 2003 19:33:56 UTC "Jeff Strickland" <beerman@yahoo.com>
wrote:

>
> "Will Honea" <whonea@codenet.net> wrote in message
> news:JxX2tWiP5BNp-pn2-dHfh4c4LGG9R@ANON.NONE.NET...
> > On Tue, 12 Aug 2003 21:45:24 UTC "DougW"
> > <post.replies@invalid.address> wrote:
> >
> > > Jeff Strickland wrote:
> > > > No return line, how does that work?
> > >
> > > My guess would be "poorly" :)
> > >
> > > > "serg" wrote ...
> > > >> yup! no return line...i'll let you guys know for sure when my kit
> arrives...
> >
> > No crap! It's enough of a pain to bleed the air out of an empty
> > line/rail with the bypass flow of the external regulator so just
> > imagine the PITA this will be if you ever happen to run out of gas.
> >
>
>
> That's easy Will, just unplug the feed line where it connects to the rail.
> The gas will come out after the pump runs for a few seconds.

Oh, it's straight forward. On the older versions all you do is open
the Schraeder valve until you get flow and all that leaves is a tiny
amount that will clear thru the by-pass - but it does take a while.
If there is NO Schrader valve and you pull the input end you still
have aair filled rail until the air is purged thru the injectors. I
don't know about the Jeep but that can be really problematic on GM V6
fuel rails - BTDT.

Whole concept doesn't make good engineering sense to me so it must be
abean counter thing...

--
Will Honea <whonea@codenet.net>

Re: new version of mpi kit
 

In message <JxX2tWiP5BNp-pn2-nFOnwB2vzd0h@ANON.NONE.NET>, "Will Honea" wrote:

>On Wed, 13 Aug 2003 19:33:56 UTC "Jeff Strickland" <beerman@yahoo.com>
>wrote:
>
>>
>> "Will Honea" <whonea@codenet.net> wrote in message
>> news:JxX2tWiP5BNp-pn2-dHfh4c4LGG9R@ANON.NONE.NET...
>> > On Tue, 12 Aug 2003 21:45:24 UTC "DougW"
>> > <post.replies@invalid.address> wrote:
>> >
>> > > Jeff Strickland wrote:
>> > > > No return line, how does that work?
>> > >
>> > > My guess would be "poorly" :)
>> > >
>> > > > "serg" wrote ...
>> > > >> yup! no return line...i'll let you guys know for sure when my kit
>> arrives...
>> >
>> > No crap! It's enough of a pain to bleed the air out of an empty
>> > line/rail with the bypass flow of the external regulator so just
>> > imagine the PITA this will be if you ever happen to run out of gas.
>> >
>>
>>
>> That's easy Will, just unplug the feed line where it connects to the rail.
>> The gas will come out after the pump runs for a few seconds.
>
>Oh, it's straight forward. On the older versions all you do is open
>the Schraeder valve until you get flow and all that leaves is a tiny
>amount that will clear thru the by-pass - but it does take a while.
>If there is NO Schrader valve and you pull the input end you still
>have aair filled rail until the air is purged thru the injectors. I
>don't know about the Jeep but that can be really problematic on GM V6
>fuel rails - BTDT.
>
>Whole concept doesn't make good engineering sense to me so it must be
>abean counter thing...

Could very well be. It may also be better than sending heated fuel back to the
tank if you're trying to control evaporative emissions.

Re: new version of mpi kit
 

While making sure the fuel never vaporizes.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/

bllsht wrote:
>
> Could very well be. It may also be better than sending heated fuel back to the
> tank if you're trying to control evaporative emissions.