fuel pressure regulator problems (?) Does the TJ even have one?

[Big_T]

Thanks for all the replies.

Ok,
Latest is:

> Error Codes show nothing is wrong anywhere.

> Distributer Cap, rotor and leads have been replaced withing the last 2000k and they are higher spec, quality ones from www.4wd.com

> Pump sounds good and quiet and the same whether I have left it half an hour or half a minute.
When I turn the key to ON, but not far enough to start, it seems to hum for less than 2 seconds before it stops.

> If I leave the Jeep sitting for a while, then turn the key to ON, and then wait for 5 or 6 seconds after the pump has had it's 2 seconds run, the Jeep starts as per normal.

So that might suggest that the pump at least is ok..right?
(pretty much exactly what ZZZZ and Red Rat have suggested)

Maybe the regulator is not working, or there is a leak in the fuel rail somewhere.

So next step is to get the fuel system pressure tested, and maybe the injectors tested...right?

I think I might do the pressure testing myself using the FSM .pdf and one of these test guages - pretty cheap on eBay.


geez...
What about injector replacements... are they expensive?, where would I source them? Apart from the dealership (goes without saying)

[Big_T]

Originally Posted by Gildo

Pressure reg is at the front end of the rail, check that the vacum line is connected, and clear. Its not electronic, and is just a spring and diaphram, you cant really test it other than pulling the return line and seeing if fuel is pumping straight through, and not pressureizing the rail.

Pretty sure it's in the fuel tank on mine (97, but technically built in 96),,, but I am just learning, so could be wrong.

[big red beast]

Mine is doing the exact same at presnt. On the rail there is a value as people have already said, from here you hook up a fuel pressure guage and run your car at idle it should from what i recall run about 3.25 bars of pressure of the equivilent in KPA / PSI - 48 kpa (+/- 2) something around there.

After you turn the key off it should drop slightly but stay around the 30's or so for some time. Mine at present drops right down to .75 BAR within 10minutes.
This means the check value is stuffed. the check value is found in the fuel pump which unfortunately is a throw away item and is found in the tank with the fuel pressure regulator. when purchased they are one until, TYNAN's just quoted me $520.00 but luck for me i get a 20% discount on that through a mate so i currently have one on order waiting for it to come in.

To answer your question directly - yes Wranglers do run a regulator in the tank but the check value is actually part of the fuel pump (anyways they are sold as one unit.

At home should take the most of 2hours to fix
Rememeber don't unbolt the tank until you've disconnected the fuel filler otherwise like my dumb arse last time you'll start to scream when you start to realise the tank isn't coming down with the jack. hehehe : )

[Big_T]

Thanks BRB, very helpful.

The FSM says:

(4) Start engine and bring to normal operating temperature.


(5) Observe test gauge. Normal operating pressure should be 339 kPa

+ - 34 kPa (49.2 psi + - 5 psi).

(6) Shut engine off.

(7) Pressure should not fall below 30 psi for five minutes.

etc etc

your guess from memory was pretty close.



FSM also says:

Fuel pressure that has dropped to 0 psi on a cooled down vehicle (engine off) is a normal condition.

When the electric fuel pump is activated, fuel pressure should immediately (1–2 seconds) rise to specification.


Abnormally long periods of cranking to restart a hot engine that has been shut down for a short period of time may be caused by:

²

Fuel pressure bleeding past a fuel injector(s).

²

Fuel pressure bleeding past the check valve in the fuel pump module.

[Big_T]

I obviously don't get it yet, but I am getting closer.

So Big Red Beast, are you just getting the pump for that cost, or the entire mudule?

It sounds a bit pricey if it just the pump... considering the option of getting this pump from the States: $91.97 USD
http://www.fuel-pumps.net/fuel-pumps...t--e-f-i-.html



If I bought one of these, will it have a check valve on it?

[Gildo]

If its the check valve, Id think there would be something that could be added in line that would do the job, its a simple 1 way valve that holds the pressure, $520 sound a bit exy to me, but Iam a titeass.
You may be right about the position of the pressure reg, Im was talking about the XJ/MJ/YJ set up not an expert on the TJ.

[cj5350]

mate might be worth bitting the bullet and hooking it up to a scanner...the snapon one I use does pump pressure test and injecter tests...one thing I notice is that you can run the pump at presure while you have the pressure guage connected...but if you have trouble starting afterwards...poss a leaking injector??? but like the other said...sound like a new pump setup...