96 4 ltr grand Cherokee fuel preasure regulator location

[drover]

Originally Posted by Lewy2001

The TJ and XJ only have a single fuel line the return is done at the regulator on the top of the in tank unit.

Thats interesting I would have thought it would be on the end of the fuel rail to bleed off excess fuel but then it does make sense to be off the regulator on the pump, excess pressure bleeds back to tank.........I'll have another dig around the manual for the ZG, changes every 2 years to the fuel delivery system makes things hard to follow...

I stand corrected, it seems like it doesn't no matter what the model, return lines from regs in or outside the tank only, nothing from the fuel rail back to tank, the line my memory was thinking about running with the fuel line I think was the evap can..

My notes show my 96 ZG had an inline fuel filter down near the tank, I used a Ryco Z570 filter..........

[Jonny Jeep]

Originally Posted by drover

The diagram above from Jonny Jeep relates to the 93/94 models.

Interesting. That pic is from the 06 ZJ FSM. It's not the first time for the FSMs to have old pics or erroneous text though.

Looking into the text more I don't see the specific text you quoted, but it does mention a pressure regulator is in the tank, which is shown on the underside of the fuel pump module.



This is the accompanying text from the FSM.

Fuel Pressure Regulator Operation:

The pressure regulator is a mechanical device that is not controlled by engine vacuum or by the powertrain control module (PCM).
The regulator is calibrated to maintain a constant pressure at the fuel pump module outlet fitting of 338 kPa ± 14 kPa (49 psi ± 2 psi). The regulator contains a diaphragm, calibrated springs and a fuel return valve.
Fuel is supplied to the regulator by the electric fuel pump. The fuel pump also contains a check valve to maintain some fuel pressure at the fuel injectors
when the engine is not operating. This will help to start the engine.

If fuel pressure at the pressure regulator exceeds 338 kPa ± 14 kPa (49 psi ± 2 psi), an internal diaphragm closes and excess fuel pressure is routed back into the fuel tank through the pressure regulator. A separate fuel return line to the engine is no longer used with any 4.0L or 5.2L engine.

Looks like 97 was the change to the TJ/XJ style combined fuel filter/regulator, so it's possible a 96 could have that type depending when the change was made, as some mid model year changes did get done on Jeeps.

[Fishframe]

If you change the fuel pump assembly look for Bosch which was OEM. I bought one recently off Amazon. Getting rare to find. The other after market pumps are crappy. Trust me, that’s why I bought a Bosch to replace my aftermarket one barely 12 months old. Also, if you diy, the fuel gauge sender arm is delicate. When fitting, if you even slightly bump it out of shape you will never have even a remote chance of accurate readings. That happened to me as well.....

[FRANKIDOWNUNDER]

I own almost the first Zg to be sold in Australia in April 1996 and yes, there is only one fuel supply pipe from the tank to the fuel rail, the other line is a vapour line to the evaporation canister. "96 &97 models have the fuel pressure regulator inside the tank as in Jonny Jeeps diagram. "98 model and on has the regulator mounted on top of the fuel pump assembly and outside of the tank.
If you don't have fuel pressure at the fuel rail start by checking if the pump is actually running, you should be able to hear it. If the pump is running then check for pressure in the fuel rail. If the pump is not running then before rushing out and buying a new one go right over the electrical supply to the pump. Especially look at the plug in the wiring down by the tank, that can often corrode and stop the pump running. Also there are two relays in the electric junction box that can also fail. One is the fuel pump relay and the other is the Automatic shut down relay which is driven by the Body Control Module. use the horn relay as a spare if you need one as it does very little work, not like the other two that are on all the time the engine is running. And of course ,check the fuel pump fuse as well, just in case it is blown. I changed all my main fuses and both fuel control relays after having occasional fuel problems with mine.

Hope that i've been some help.

Denis.

[drover]

Not the first time the book doesn't quite line up, I think having ours built in Austria and not the USA has meant little changes along the line...... Always liked the ZG still the most capable 4x4 Grands for out bush.....nice height and does it straight out of the box.