I just replaced the regulator spring/diaphragm in my '91 3.1 and the pressure dropped from 41 psi to 23 psi in 15 minutes. Is there any way to do the install incorrectly? It seemed straight forward enough. Is there any other route for gas to leak out? The injectors are very recent ones from Southbay so I don't suspect them at this point. I was going to pinch the return line but don't know off hand which one it is. Also, what is the round device that one of the fuel lines runs through? The new spring/diaphragm came with a few small ring seals but I didn't see anywhere under the regulator cap for them to go. Any guidance on what to check?

 

Wish I could help you!!!

 

Thanks. I was hoping to get back to the logging but want to nail down the fuel pressure first.

 

What fpr did you end up getting?? Are you sure everything is attatched correctly? I wana see ya start logging to, i havent dont it in a while since i got on this turbo build.

 

Fuel pump has a check valve too, put the gauge on it, cycle the key, pinch off the rubber section of the feed & return lines. Wait & see if it drops. Might be a slightly leaky injector.
You loss of pressure isn't too bad.

 

I hadn't thought of pinching both lines. I hope it's not injectors they're only a few months old. What's the round piece on one of the lines that sits at the front of the block?

 

Double check to make sure the FPR screws are tight... Last time I replaced my stock FPR I had a lot of fun getting those tight enough (even broke a couple... Good thing I had a spare rail!).

 

I see no leaks from around the cap and I did get the screws pretty tight. I didn't break any of the screw but I did break the Torx security drive. Bought a couple of spares at the local hardware store. And what the round thing one of the fuel lines goes through? Sits at the front of the block.???

 

Well, the best way to describe that thing, I suppose, is that it's a shock absorber for the fuel system. It shouldn't be leaking as it's almost impossible for it to do so without it being terribly rusted, and it's built into the fuel pressure line, so it can't be changed.

 

pull the plugs, check to see if you have any wet cylinders which be indicative of a leaky injector.
If all else fails, send the injectors in, we will be more than happy to put them on the bench to check them out for you..... no charge of course.

www.southbayfuelinjectors.com
516-492-6504

 

Thanks. But what's the round part that one of fuel lines goes through? Sits at the front of the V. ??????

 

The round thing...

 

Must have been typing at the same time. Thanks.

 

Which means that's the input to the fuel rail?

 

Yes, the PRESSURE line is the input and the RETURN line is the output (return generally doesn't have pressure unless a line is blocked).