I rented a fuel pressure guage from autozone and my pressure is between 40 and 50 psi (needs to be ~60). Worse it bleeds off to about 10 psi in 30 seconds or so. I obviously have a leak somewhere but I cannot find it. I replaced the fuel pressure regulator recently, it improved mileage but didnt stop the leak. I replaced the fuel pump that was failing anyway (thinking the pulsator might be leaking) but it turned out to be an aftermarket with no pulsator. Now its cold and the truck wont start unless its around 50F.

I took the upper plenum off again, and pressurized the fuel system, and cannot find any leaks. There were a few puddles (maybe left from last time?) of gas in the plenum. I laid rags under the fpr and the nut kit and ran the pump several times and cannot detect a bit of gas.

The pressure is leaking very fast so it has to be going somewhere right? I've inspected the fuel lines everywhere I can and see no leaks. I want to test just the pump but do not have a fuel pipe shut off valve to bypass the rest of the fuel system.
Only the fuel line between the fuel pump and the spider is pressurized right?
I might have a broken gas tank vent valve from when the pump was replaced, but that would not let the pressure bleed off right?
If the spider is leaking, will I be able to see it? Where else could the fuel pressure be leaking? seems like it must be in the tank or in the engine. Any suggestions are highly appreciated.

 

They sell UV dye that goes in your fuel, you can always try that

 

If it holds below 10psi, then the leak is likely in the engine.

If you have been driving the truck since you replaced the FPR, the fuel would have evaporated by now for sure so the presence of fuel in the lower intake means that there is still a leak inside there.

When you replaced the FPR, did you also replace the internal fuel lines (aka 'nut kit')?

 

I did not replace the nut kit because I didn't see washing on the drivers side. However, there was a tiny puddle near the nut kit both times. Could it be leaking only when the car is warm or something? I was thinking about going ahead and replacing the nut kit, but most of the fuel is on the other side.

Here is a (crappy) video of me running the pump. watch how fast the pressure drops at the end. If the pressure is leaking that fast, shouldn't I be able to see where its leaking?
http://www.youtube.com/watch?v=kuqA8tlstsw
if you cant read the dial its peaks at 50 and drops to 15 almost immediately.
Here are some pics as well
I mopped up most of the puddles, there seems to be more washing on the drivers side than there was last time, right above the puddle I mopped up(the bolt at the top).
I also pulled out each injector hose and ran the pump to see if it was stuck open and leaking, but saw no gas.(except the drivers side rear that has a broken tab so i couldnt get it out).

II just keep thinking that if its losing pressure that fast I should be able to see where its going.

 

From what I can tell is that it has pressure when the pump is running and when I hear it kick off you loose pressure almost immediately....correct??

 

yes, the pressure drops from 50 to 15 as soon as the pump stops, settling in at 10 after a minute or so.

I'm starting to wonder if i got that fuel pressure regulator in there right last time, it looks like it might not be tight
https://i.imgur.com/642qR.jpg

 

I too had the very same problem.....internal leak in spider assy., mine was leaking @ the top where the harness plugs in!!! I replaced the spider assy. and problem solved good luck!!!! it was 300.00 well spent...

 

Thought I would mention after I installed my last fuel pump in my 92 S-10 when I turn key on it would quickly jump to 60 + pounds, them quickly bleed down to about 25. I change positions with my ground wire, that cured it.

 

Thanks everyone for the replys, been busy over the holidays. I found a remanufactured fuel injector at Oriellys for $180. It is listed under mfi, they don't have cfi listed in their computer. The guy on the phone says they are probably the same, but I dont see any support for that searching on here. The picture looks correct so maybe its listed wrong, I think I will go get it to compare. I dont know if this link will work.
http://www.oreillyauto.com/site/c/de...2521&ppt=C0024
its a BWD fuel injector
Part Number: 27096
Line: BWD

If anyone is familiar with Oriellys funky parts system let me know.
This is not ideal but I have to borrow the money for this so if I can get it that cheap I will.

 

The image on the page in that link is correct for the CPI spider.