Jeep Enthusiast Forums banner

how do I check the fuel pressure regulator on the rail (2.5)

14K views 5 replies 4 participants last post by  carcollector 
#1 · (Edited)
how do I check fuel pressure and regulator on the rail - no valve on rail
1997 2.5 MANUAL: I am having some major drivability issues

I am suspecting a fuel problem. The fuel pump was replaced, but I do not know how to check the presure regulator on the fuel rail.

I tried hooking a vacum hose and sucking (lol) and using a check valve to get it to hold the pressure, but the middle nipple will not let anything suck or blow through it (lol- that sounds weird too) anyway, How do I check it?????
 
#4 ·
The standard type - I guess because there is no reed valve on the rail in 1997, Pressure needs to be checked at the regulator that is in (or at the top of) the tank.

I am suspecting/hoping it is the fuel injector pressure regulator that is on the front side of the fuel rail and has a vacum attached to it. I have taken it off, applied vacum to the nipple, and I can not even blow through it.

Unless, since the regulator is in the tank it just restricts the flow to the rail
This system does NOT have a return line from the rail

Autozone has a GP sorenson part #800-430 listed but not available in stores or through shipping

The Jeep seems to be starving for gas, a new fuel pump has already been thown at it, it threw a pO320 code for "no speed signal to distributor" so I replaced distributor which has a camshaft sensor in it, and if it was the cranksensor I do not believe it would start and idle as good as it does. It just bogs/stalls upon acceleration unless you really ease up the rpms. i can get it to hold up to 4000rpms steadily, but if you let off and back on it wants to stall.

I had a simular problem with a YJ and I replaced that part and it was OK - but I do not want to special order something without checking it first. And I really do not want to drop the tank without checking the pressure first either.

any suggestions or methods?
 
#5 ·
DIAGNOSIS AND TESTING (Continued)
WARNING: THE FUEL SYSTEM IS UNDER CONSTANT
FUEL PRESSURE EVEN WITH THE ENGINE
OFF BEFORE DISCONNECTING FUEL LINE AT
FUEL RAIL, THIS PRESSURE MUST BE RELEASED.
REFER TO THE FUEL SYSTEM PRESSURE
RELEASE PROCEDURE.
(1) Release fuel pressure. Refer to the Fuel System
Pressure Release Procedure.
(2) Disconnect latch clip and fuel line at fuel rail.
Refer to Quick-Connect Fittings for procedures. This
can be found in this section of the group.
(3) Connect adapter tool number 6539 or 6631
(Fig. 5) into fuel rail. Be sure adapter tool is fully
seated into fuel rail.
Fig. 5 Adapter Tool 6539 or 6631
(4) Install latch clip to fuel rail. If latch clip can
not be fully seated into fuel rail, check for adapter
tool not fully seated to fuel rail.
(5) Connect vehicle fuel line into adapter tool. Be
sure fuel line is fully seated into adapter tool.
(6) Remove protective cap at test port "T" on
adapter tool.
(7) Connect the 0-414 kPa (0-60 psi) fuel pressure
gauge (from gauge set 5069) to the test port "T".
(8) Start engine and note pressure gauge reading .
Fuel pressure should be 338 kPa ± 5 kPa (49.0 psi ±
2 psi) at idle.
(9) If pressure is at 0 psi, connect DRB scan tool
and refer to the appropriate Powertrain Diagnostics
Procedures service manual.
(10) If operating pressure is above 51 .0 psi, fuel
pump is OK but pressure regulator is defective.
Replace fuel filter/fuel pressure regulator assembly.
(11) After performing pressure test, install fuel
line into fuel rail. Install latch clip into fuel rail.
Refer to Quick-Connect Fittings in the Removal/Installation
section of this group for procedures.
FUEL PUMP PRESSURE TEST-4 .01- ENGINE
TJ
NOTE: The fuel pressure test port is used on certain
engines only. If equipped, the test port will be
located on the fuel rail (Fig. 4). A sealing cap is
screwed onto the test port.
All fuel systems are equipped with a fuel tank
module mounted, combination fuel filter/fuel pressure
regulator. The fuel pressure regulator is not controlled
by engine vacuum.
With engine at idle speed, system fuel pressure
should be 338 kPa ± 5 kPa (49.0 psi ± 2 psi).
WARNING: DO NOT ALLOW FUEL TO SPILL ONTO
THE ENGINE INTAKE OR EXHAUST MANIFOLDS.
PLACE SHOP TOWELS UNDER AND AROUND THE
PRESSURE PORT TO ABSORB FUEL.
WARNING: WEAR PROPER EYE PROTECTION
WHEN TESTING FUEL SYSTEM PRESSURE.
(1) Remove protective cap at fuel rail test port.
Connect the 0-414 kPa (0-60 psi) fuel pressure gauge
(from gauge set 5069) to test port pressure fitting on
fuel rail
 
#6 ·
wow thanks -
With the regulator of the rail off, I had my 12yo daughter turn the key on briefly and caught the fuel that came out unsuprisingly. Then, I put my palm over the opening and she hit it again to see if there was any pressure behind it and there was, but nothing crazy (but that was just the prime) - That was before I got your reply... I wore safety glasses but didn't light the cigarette in my mouth.

I like your fancy scientific way better and I will have to get the right adapter or guage tommorrow

Should I just drop the tank and check the filter and prior pump install tonight since I am bored?
I can start it with the tank on the ground to check the pressure if everything looks OK

I would hate to find any other ways subconciously to burn the thing and myself to the ground before then
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top