Yes, I've already done a search on it... Just wanted opinions on my situation... My car is hard to start after it sits for a while... Once it starts and I shut it down and restart it, it starts fine... I've also been getting detonation at mid throttle lately... I'm using 93 octane gas... I hooked up my fuel pressure gauge and turned the key and the pressure rises to 44 PSI as the pump comes on... As soon as the pump shuts off it drops to 0 within 10 seconds... At idle I'm getting 36 PSI... I removed the vacuum hose from the regulator and it's dry... On shoebox's site he suggests using vise grips with rubber hose to close off the return line on the regulator... I looked at the line thinking it was rubber but it turns out it's only a cover for the harder line underneath... With the age of my car, I'm afraid of cracking or possibly crimping the line doing it that way... Any other way of testing the regulator? I know a faulty regulator or bad fuel pump check valve would cause the pressure drop, but would either one cause the detonation I'm getting as well?

 

It might be an injector. if you had a dirty injector that wasn't closing all the way, it would bleed the pressure off. I guess you could pull the injectors and leave them still on the fuel rail. tehy turm the key on and see if there is one that is leaking. This maybe the reason you are having detonation problem.

Your fuel pressures look prefect to me. if you don't find a leaky injector. I might start by replacing the regulator. it isn't don't cost alot and if that doesn't fix it. I would say it is the pump.

good luck

 

If it were an injector you shouldn't be getting detonation at mid-throttle, and you should hear a hissing sound from the throttle body/intake. I know what it sounds like because I have a few leaky injectors on my 305. Holding off replacing them til I do everything at once. Detonation would be because fuel pressure is too low, or something isn't getting enough fuel. Your fuel pressure should not drop that quickly. Find somewhere to pinch the return line. If the pressure doesn't drop, then its your fuel pressure regulator. If still drops, then its the check valve on the fuel pump. My guess is it's the check valve but ya never know.