96 XJ Country Fule delivery problem

Quick history, low pressure, 15PSI, would idle but not drive, unique year where pump and pressure regulator are in tank. Picked up Bosch 69544 pump, NAPA 2-19679 regulator, installed and also repaired fried connector on pump (ground wire overheated and melted connector). Get 40 PSI at rail now (not sure this is high enough, could be regulator from NAPA?), but drops to zero when key off, AND I don't get any "priming" of the pump at key on. I plan to put an in line check valve to fix key off pressure, but I need advice on the pump not priming with key on, takes three tries but she'll start once the pump gets enough voltage to bring pressure up (competing with starter for voltage when starting)...or if anyone can confirm the part numbers I used to be incorrect, I will fix it the right way, now that I've done it, its not too bad to do it again, this model has pump on front of tank ...

Correction on that in line check valve, read others had tried this with units that don't have regulator and return line at the fuel rail, basically if you put a check valve between the regulator and the rail you run risk of overpressure for some reason, but behind regulator the regulator keeps the correct pressure, too many notes from people who had the fuel line come apart at the engine and possible fires ...

I am glad to see you posted that correction. As soon as I saw what you typed in the first post I was going to warn you to do a little research before installing a check valve without a return line.

If it is not holding pressure at all then you still have something wrong in terms of parts. Could be in the tank or a bad injector (or more than one bad injector).

I used a Bosch pump and a Crown regulator when I went through this on my '96. I got the regulator from Morris 4x4 and the pump off ebay. I have 49 psi at the rail.

I don't have any advice for where to start on the priming issue, but I would get the pressure drop licked first and then see if that had any impact on the priming.

Edit to add: Went looking for part numbers I used. Regulator is a Crown 53030001. It appears I did not record what P/N Bosch fuel pump.
Write-up is here if you are interested, but it sounds like you already got it figured out that this is serviceable: http://www.naxja.org/forum/showthread.php?t=1107991

Hi Anak, I think it was your old thread that originally sent me in the right direction. I used your Crown regulator part number as reference for NAPA unit.
I think I have something electrical regarding pump priming, I've only had my XJ about 18 months, first Jeep and I am loving it, but high mileage and starting to see these kinds of things. The priming may have never worked, but with pressure in the rail probably not an issue, but now it is.
Do you know for certain if the check valve is in the pump or the regulator?
BTW< thanks for the lead on that video on YouTube, I have same rig and saw him get a face full of gas too, although admittedly I did same but for different reason, full tank of gas, using old pump to remove some, and had hose on tank outlet, splashed in my face when I pulled it off ...

You know, I may be wrong about the NAPA reference, I think I took yoru Crown part number to PepBoys auto parts and they had a cross referenc but something not stocked, so I ended up at NAPA where maybe this unit is not correct.... hoping someone else joins thread and can confirm this, but being new to Jeeps I am a little lost ...

Anyone else know how the priming circuit works? I can paperclip the relay socket and force pump to run, and if it starts the pressure is good, so what drives the pump at key on? the ECM module?

Anak, quick note, old pressure regulator that came out had a Chrysler symbol on it and numbers stamped on it 4669239 3075, will be digging to see if the cross references to anything current, I think I have the wrong check valve in, pressure 10 psi lower than yours and now check valve .....

MMAFreak said:

Anyone else know how the priming circuit works? I can paperclip the relay socket and force pump to run, and if it starts the pressure is good, so what drives the pump at key on? the ECM module?

Click to expand...

The pump will only run for 2-3 seconds after the key is
turned on, unless the ECM senses the engine is turning
over. This is for safety in event of an accident.

I do not know for certain which of the components is the check valve. I recall reading somewhere that both of them (fuel pump and pressure regulator) function as check valves, but I cannot confirm that is accurate. I simply replaced both and that solved my problem.

I appreciate your mention of the part number on the Chrysler regulator you removed and I would be curious to know what you find in questing for an alternative.

Hey Runnin'OnEmpty ... thanks, I did confirm, with fuel pressure gauge on rail, turn key on, no pressure, no noise, nothing happens ... get her started and pressure is at about ~40psi (which I now believe is wrong, should be 49 psi and confirmed regulator NAPA sold me is rated at 39psi, i.e. wrong one), trying to figure out what controls pump prime, probably ECM but trying to confirm.

Anak, I am going to all NAPA store this morning, explain the problem and that one of the parts they sold me is wrong parts, wrong pressure and no check valve, ask them to do the leg work for me ... will post all details that I can, parts numbers and specs, etc. Would post some pictures if I can figure out how to do it in here ...

From what I think I have managed to figure out the FPR should produce 39 psi if connected to vacuum ('95 and down, H.O.) and 49 psi if open to atmospheric pressure ('96).

Posting of pictures requires hosting them on another site (photobucket seems to be the popular suggestion) and then linking their location to here. It is also best to resize them down to something like 640 x 580 so they are not bigger than everyone's screen.