i have read it at one point but cant seem to find it again. whats the stock/proper fuel pressure for a 95 s/c? i read that you take two readings one with the vacuum line attached to the regulator and one without. is that correct? and if so what pressures should i be seeing?


the reason i am asking is that, i did a live scan and noticed that my LTFT and STFT was at 136-145. from reading on here and the bonneville site. the starting 0 is actually read as 128. i havent checked the pressure yet but how do i know if its the pump or regulator that is going bad? twice in the past week my engine light came on saying lean condition so i have to fix it fast. can i swap in the walbro 255lph pump like in the series 2 or ???

From here:
http://www.pontiacbonnevilleclub.com/forum/viewtopic.php?f=44&t=1660

"Key on, ignition off, you must have 41-47 psi. At idle, you should have 41 psi minimum, and it should jump to 42-44 psi when you pull the vacuum line off the fuel pressure regulator at idle. If it doesn't meet these specs, your problem is either a fuel filter, fuel pump, or fuel pressure regulator."


If you are unsure, fire in a new FPR as they are fairly cheap as easy to replace. Also be sure to check the fuel fiter too. You could use a walbro if you really wanted to, but there's no way you will out flow a stock pump really with the series one. Personally I have a walbro on the way, but the only reason was that up here in canada no-one wanted to sell me JUST the pump and not the entire canister assy. For me it was cheaper to go with a 255lph.... that and eventually im going to get crazy with this car when it goes off the road

one more question. i noticed when i was doing my scan. i build boost at idle. i figured the bypass valve would have opened. is boost at idle normal or do i have to lube the valve up or something?

It would be hard to know for sure without looking at the acutator on the side of the supercharger or installing an actual boost gauge. The 95 with its OBD "1.5" has some funny issues and one of them is that its boost reading will only be 0% or 100%. I believe mine in park or N will show boost at 100% even if there is no boost being built. When it is in gear though you should find that it goes to 0% until you are heavy enough on the throttle that the Boost bypass solinoid fires and then it will change to 100%. So in short, the boost reading is quite useless with OBD 1.5. And actual boost under idle should not be happening.