Lizard928

High flow steel cats last a year on average.

Tom in Austin

Wow, never would have guessed that ...

finally!

THAT SUCKS! Have had hi-flow cats on other cars and they lasted 4+ years easily! for what they cost should last MUCH longer than that!

soontobered84

If you are running rich.

finally!

Therein lies the rub.. Have checked everything except FPR and dampener..

Sean, I am coming to your inspection guy tomorrow morning (11/01/12), could I drop by and you could test them for me?

SeanR

Sure can, give me a call when you are almost there and I'll see if I can get away for a few minutes.

finally!

I will be at the inspection place at 8:00 then to your place directly after.

Do you have FPR and dampener there in case they need replacing?

SeanR

I won't be back to the house until just before 9 so if I'm not here just wait for me. Taking the kid to school.

Don't have either in stock but can get same day if we need one, delivery is usually around noon.

safulop

Can somebody please clue me in, what is "FPR" and the "dampener" mentioned here? I'd like to check mine as I too have a low-RPM rich issue.

Thanks,

Sean

Rob Edwards

Fuel Pressure Regulator = located between the passenger side rear of the fuel rail and the rear "U" fuel hose.

Damper = two of them, front one is between fuel inlet line, the front of the driver's side fuel rail, and the the front crossover hose. The rear one is on the driver's side in back. They 'dampen' fluctuations in fuel pressure generated by the external fuel pump.

All have a rubber vacuum elbow attached. Pull the 3mm plastic hose out of the elbow and pull a vacuum on each damper or FPRwith your mityvac. They should hold vacuum. If they don't you have a split diaphragm.

Here's a shot of an FPR's guts:

Speedtoys

Why does the damper, need a vacuum hose then, if all it is...is a retard chamber.

dprantl

My high-flow cats have been good for 4 years worth of Atlanta emission inspections so far, but I have a wideband gauge so I know my car's AFR is good all the time.

Dan
'91 928GT S/C 475hp/460lb.ft

victor25

Because if it had no vacuum line and it leaked, the fuel will just dump all over the engine... VERY BAD... I know this first hand!! As I made the mistake of pulling the vacuum line off the front damper once while the car was running. Yeah, gas sprayed out and caught fire!!!

That told me I need new dampers, and new plug wires.... and almost a whole new car!!

This could very well be your problem. Does the car tend to start hard when warm?? If so that's a bid tell tale sign

Speedtoys

Huh..ive had a ton of cars..turbo and not..and not one..ever had a failed damper, much less a vacuum port on it.

A few manuf's do, but by far not all in a cursory search on google, and few aftermarket ones as well.


Not worth retrofitting, just wondering.

dprantl

There are quite a few reports of the diaphragms in dampers and regulators failing on 928's. Maybe it is just the type used in this case.

Dan
'91 928GT S/C 475hp/460lb.ft