Blew my AFPR during boost leak test, please read to help prevent this from happening to you

[kchaazz]

Okay, so tonight, I decided to do a boost leak test, as I usually do every three months or so. Put my regulated setup on and put a steady, regulated 30 psi into the system. BOV line leaked a bit at teh blow off valve, nothing a new ziptie didnt fix.
Anyway, went to fire her up, and noticed it sounded like it was misfiring, and wideband was in the 11:1 range, so I thought maybe I had just gotten a bit of soapy water on the coilpack or something.
I decided right away to see if pulling a vac line would lean it back out a bit, and if so, it was ignition related. I chose the fuel pressure regulator line and when I pulled it, fuel sprayed out. A true, "oh shit" moment. I shut her down, grabbed a hose and blasted the gasoline off the manifold right away. This all happened over a period of maybe two minutes.

Worried that I may have some fuel pooled in the mani, I inserted the vac line into an empty soda bottle and started it back up and within 20 seconds, the wideband was back in the high 14.xx range, so hopefully there wasnt too much fuel going past the rings into the oil, though Im still going to change the oil after I get the reg sorted. Anyway, its a Fuelab 535 "mini" reg that I have only had around 14 months, so Im sure theyll warranty it no problem, but the real question is "WTF?", because obviously the diaphragm blew out with just 30 psi MANIFOLD pressure in the signal line during the boost leak test. Has this ever happened to any of you? Im worried cause Im running 28 psi on my FP Red, and if the diaphragm fragged with 30 psi in the vac line, it may fry again under boost and Im reasonably sure It would hydrolock the motor at wide open throttle and maybe even blow my ass up

 

[kchaazz]

Update: I spoke with a representative from thecompany, and he was very helpful with some information regarding this problem after I fully explained the boost leak test. The following is his reply, and I believe this can be useful to everyone:

"Pressurizing the top side could certainly tear the diaphragm if the fuel system was not turned on. Under normal running circumstances, the diaphragm never really sees 30psi of pressure. The reason being is that the fuel is pressing against the diaphragm on the bottom side with pretty much the same force as the air (and spring) is pressing on the top side. Under the correct conditions, the diaphragms don’t really wear out. They should last nearly as long as the regulator."
"If the damage is a tear, it was most likely from the air pressure. If it’s a hole, it was from some kind of debris. There could have also been a small pinhole that opened up from the air pressure as well."

My diaphragm has a tear in it. I believe this can be avoided by performing the boost leak test in two stages. First, perform the test at only 15 psi or so, with the regulator vac line connected, as Im reasonably sure a leak at the adjustment screw and or vacuum line will show up. Next, disconnect the vac line from the reg, plug it, and then test to your higher pressure- in my case, 30 psi. This should prevent the diaphragm from tearing due to over pressurizing the vacuum chamber of the reg without any pressure in the fuel chamber to prevent over extending the diaphragm.

What are your thoughts?

 

[DJ23GSX]

Makes perfect sense to me. I've had to replace diaphragm's in two different regulators. I'm sure this had something to do with it.