After a search, I found that the output pressure on the Adv. Evap System Fuel pump is 36 psi. My fuel rail reading was 10 psi at the Number 2 key position, engine off and 20 psi truck running (with or without the fuel pressure regulator vacuum line attached (although the truck wouldn't start with vacuum line unattached) regardless of rpms). Is the fuel rail pressure supposed to be the same as the fuel pump output? Asked another way, what is the proper 1. fuel pump output pressure 2. the fuel rail pressure cold off and running. thanks Phil

 

With the engine running you should have mid 30's PSI at the fuel rail.

 

I'd replace the filter if you haven't already done that (I can't remember if you have) and check the pressure again.
If still low, check the pressure at some point before the regulator.
If low, replace the pump, if ok, replace the pressure regulator.

 

Things are getting clearer even as the get odder. I changed out the pump in the fuel pump assembly. Got a Carter/Airtex E3270 at Kragens for $90, one year warranty. It was slightly shorter and a tiny bit bigger diameter than the oem version. The fuel line off of the original pump would not come off of the stub. Ended up having to cut it off. Used 3/8ths fuel line with hose clamps. Had to ream out the L-bracket that guides the fuel line from the pump up to the top of the assembly. Got it all back together and put it back in the truck. Started it up and ran it a few minutes. Turned it off and hooked up the fuel pressure gauge. with the key at position 2 it read 30 psi (it had been 10 psi with the old pump). Started it up and it dropped to 22 psi. That is the odd part. I don't know if the pressure regulator is limiting the psi to 22 lbs. I don't know if the fuel pressure regulator is limiting the pressure to 22 psi or if that is how it should run. I will try it out in the morning and see if I still have the hard start issue. I am still wondering if the 1177 and 1179 codes are fuel pressure related. While I was at it I also changed out the fuel filter. I had changed it out last year, about 7,000 miles ago, but it can't hurt, I also wanted to take that part out of the equation. Next up is to change the pressure regulator if I continue to have the hard start problem. The change out was rather straight forward, took about 2 hours total, including a trip to Kragens. Also cleaned up a few items around the truck, including the fuel filter. Certainly worth the $300 savings over a whole near fuel pump assembly, I think.......the pressure still seems strange. 22 psi seems rather low. Phil

99 DI 100,319 miles

 

I guess you were in a hurry. $68 here: http://www.amazon.com/gp/product/B000C9OSAM
Delco strainer TS7 works with it.

 

Saturdays are too few and far between. $20 bucks didn't seem like it was worth the wait. They also have some on EBAY for about $55. I did note one other reading. When I take the vacuum line off of the fuel pressure regulator and the truck is running, it goes from 22 psi to 30 psi. When I reconnect the vacuum line, it drops back to 22 psi. The truck also has a bit of a rough idle. Could it be the fuel pressure regulator? Anything else control the fuel pressure? Dang, this isn't so much fun anymore.....Phil

 

Not sure if this will help, I stumbled across this today and remembered your fuel pump issue. I haven't completely read either thread.

http://www.discoweb.org/forums/showthread.php?t=14451


Good Luck

 

I understand prefectly. I've paid a price premium before when I was in a hurry. I was posting that more for people who have the luxury of waiting, or want to order one to have as a spare.

 

Wow, I went out this morning, turned the key and viola! It started right up. The truck feels like my Porsche, well, not really, but you can't believe the performance difference. It seems much quicker, I know, it is a bit of an oxymoron when talking about a discovery. But really, what a difference, much more like the DII in off the line performance and in acceleration. Now to clear the CLE, hopefully it was from fuel starvation and will now stay off. Thanks to all that chimed in. The link to the fuel pump rebuild listed by LuvtoDisco http://www.discoweb.org/forums/showthread.php?t=14451
was very accurate. The notes that I would make would be
1. the Airtex/Carter Fuel Pump that I bought was a little shorter and slighter greater in girth than the OEM pump.
2. It takes more than one set of hands to get the four clips off the the assembly housing.
3. Buy about a foot of fuel line, the old line will not come off without cutting it off.
4. Put the Pump Seal on the tank and then slide the pump assembly through the seal. The seal system actually has two parts, one that fits around the pump assembly and one that rings the gas tank opening. The two mate together. Again, it is much easier to seat the pump seal on the tank seal and then slide the pump into the pump seal.
5. Change your fuel filter at the same time that you change the pump, eliminate any potential issues.
6. When taking the pump assembly out of the tank, note that it sits in a plastic seat that is mounted to the tank, they are both white plastic or nylon. Make sure that you pull, pry the pump assembly and not the tank seat. There is a seam between the two.
7. Having less than a full tank makes the job a little less messy..........believe me.


I still can't figure out the fuel pressure issue, but for now the truck is running great. I will note the gas mileage on the next fill-up and see if the new pump had an effect.

Thanks again, Phil
1999 DI 100k miles
2001 DII 76k miles

 

Just a brief update, I have been out of town for the past week or so. I got in the 99 Discovery I last night for a quick run to Orange County, remember that two weeks ago, I replaced the fuel pump in the fuel pump assembly. I also put hose clamps on the breather tube from the passenger valve cover gasket to the intake manifold. The check engine light had been on for several months, everytime that I cleared it it came back with 10 miles or so. It was throwing codes 1178 and 1179 as I recall. Last night I jump in and low and behold, no CEL. Drove a couple of hundred miles, no CEL and got about 17 mpg at 75 to 80 miles per hour and 15 miles of city traffic. Wow, what a pleasant surprise. Not sure if it was the new fuel pump or the hose clamps, but something worked. Running great, other than a small hiccup in the idle from time to time. Hope this helps. Phil 1999 Discovery I 100,000 miles, 2001 Discovery II with 76,000 miles