Speedtoys

what are you likely to feel/notice when you get bad one(s)?

Thanks!

h011yw00d

I had a bad FPR that filled the intake with gas

Ducman82

hard start when hot.
my dampener leaked past the diaphragm in to the intake, made it
super rich after it sat while hot.

Speedtoys

Its like this..I smell fuel, almost -taste- it in the vac line from the rear damper.

But it holds vacuum over night, and no visible liquid fuel.

So..its buggin me. New ones on order, but..short of a fully blown leaky one...will it scre up idle, etc?

Leon Speed

Mine hold vacuum too, no fuel coming out of the vacuum line, but there is fuel smell. Only items I didn't replace during the intake refresh. I have steady idle.

granprixweiss928

My pass side has fuel coming out of vac line. New one in the mail. Drivers side suspect, but it looks newer so I decided to try one side at a time.

The Forgotten On

If you are going to replace them do a little research and buy using the OEM part numbers. I saved over $100 each by doing so compared to buying genuine Porsche. They were about $70 each for my 1981. For people looking the numbers are Bosch 0280160215 Fuel Pressure Regulator, you need two of those and you only need one Bosch 0280161008 Fuel Pressure Damper. It never hurt anyone to be cheap and pay less for the same part

jcorenman

It would especially mess up your idle (mixture-wise), if it is leaking. It may be only a small amount of fuel, but at idle there is only a very small amount of air.

Don't trust a static vacuum test: The pressure across the diaphragm is only 15 psi, at most (i.e. one atmosphere). With the engine running, the pressure across the diaphragm will be 55 psi, same as injector pressure.

If you smell fuel in the vac lines to the regulator or dampers, then I think it has to be leaking. It will be interesting to see if the idle mixture is any different with new regulator/dampers.

Cheers, Jim

Stromius

Could it be leaky injectors??

Speedtoys

Thanks Jim. Roger has them on the way.

FredR

Remember- the diaphragm is there to equalise pressure with the inlet manifold/ dampen fuel surge pulses and it has to withstand fuel pressure in the rail. The classic test has always been to put one's pinky over the spout and then sniff to see if it "smells of fuel"- not to see if fuel is actually gushing out [which of course would be a really bad thing!- haha].

Sad to say in our part of the world the fuel pressure reg and the dampers seem to be on the 5 year pre-emptive list- probably because the heat degrades the diaphragm faster.

Guess how old mine are now?

Another never ending saga [The Force is with me- it tells me there is a British Expat in Texas grinning].

Regards

Fred

granprixweiss928

My Car I know has at least one bad press reg ( at the back of the engine, 4.5L 1981) cause if I pull the vac line and then put my finger on the nipple, my finger is wet with fuel. Car smells rich when starting cold. Passed smog just fine tho.

Brent

My symptoms were rough running and leaning out A/F ratio 18+ on moderate to hard acceleration. This happened last year down at Third Coast. Initial diagnosis was fuel pumps, internal and external, though both were about three years old. Internal pump checked out and external was changed out with new fuel filter. Still was running lean but I was able to limp the car back to Kansas. Fuel pressure was holding going by the fuel pressure gauge at the end of the rail. I didn't have a MityVac at that time. The vacuum line to the FPR had a very slight smell of fuel, not wet at all. So changed out FPR and all was back to normal.