P38 Fuel Pressure & Code P1179 - Land Rovers Only

ikoinu · 02-15-2007, 04:59 PM

Anybody have an idea on this one?
I recently had code P1179 come up and have been chasing the problem ever since.
The deal is I recently installed a K&N filter and I do not know if it created the problem.
I have cleaned the MAS with CRC, replaced the plugs, checked the hoses, no deal.
My fuel pressure reading on the rail is 30psi at idle, which seems a little low as the Rave cd lists the fuel pump pressure as being 34-37.
Question is, what is the rail pressure supposed to be?
When vacuum hose is removed from regulator pressure goes to 38psi, and when the ignition is turned on without starting it the pressure goes to 38 for 20 seconds and then drops to 34.
Pressure maintains 30psi after ignition is turned off.

Otherwise she runs fine and no other codes are showing.
Anybody have any ideas? Or at least does someone know the proper pressure while running for the fuel rail?

ikoinu · 02-16-2007, 11:36 PM

Nobody knows the fuel pressure on the rail of a healthy P38?

Rovin4life · 02-17-2007, 06:14 AM

check the fuel pressure regulator vacuum hose for leaks.

also too check the fuel pressure leakdown test.

start it up and turn off and leave for a half an hour. it shouldn't lower.

ikoinu · 02-17-2007, 04:34 PM

Thanks for the reply. I've done all that, but I don't have a point of reference. That's why I'm trying to see if anybody knows what a healthy rr should read at the rail while running.

Rovin4life · 02-17-2007, 04:44 PM

your a little low but if you want to see if the regulator is messed up then take a vacuum guage and check to see if it changes along with the idle.

are you certain you have no pcv leaks or blocked hoses.

ikoinu · 02-17-2007, 09:48 PM

I have cleaned out the oil separator already and all hoses are in good working order. The fuel filter just got changed out too. I will test the vacuum to the regulator tommorrow and see. Just have to figure out- fuel pump or regulator? Keep the ideas coming, I appreciate it!

ikoinu · 02-18-2007, 03:02 PM

Checked the vacuum and it's running 15 inHG of pressure. Could not find any reference on rave as to what it should be. The pressure at the manifold makes the regulator run the fuel pressure lower, so the only way it could be running high (and the fuel pressure run low)is if I had bad rings and was getting some blowby which was pressurizing the crankcase. If anybody knows the proper manifold pressure or could measure their's and let me know I would be grateful.